"Commander Kinsey" wrote in message
news
On Sat, 22 Jun 2019 19:14:07 +0100, Rod Speed
wrote:



"Bod" wrote in message
...
On 22/06/2019 18:02, Rod Speed wrote:


"trader_4" wrote in message
...
On Saturday, June 22, 2019 at 11:45:19 AM UTC-4, Rod Speed wrote:
"trader_4" wrote in message
...
On Friday, June 21, 2019 at 6:48:31 PM UTC-4,
wrote:
On Fri, 21 Jun 2019 23:15:21 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian

wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know
when to
switch to trickle charge? I can understand it noticing a drop
in
charging current if the battery is on its own, but what if a
random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change? That's determined by the
alternator or
charger. Let's say the charger/alternator gives out 14.4V
initially, to
charge the battery quickly. It'll just sit at 14.4V forever,
providing
the charger can give out enough current to charge the slightly
flat
battery and power any connected loads. If the battery had no
loads
connected, it would take a lot less current when it became full,
but the
voltage would stay the same. If the charger monitored the
current it
was providing, how does it know if the battery is still charging
at 10
amps, or if the battery is full and there's a 10 amp load?

Not really true with anything but the most primative regulator
like
you might see on an old outboard. Voltage is regulated somewhere
between 13.x and 14.x, not just reflecting what the alternator can
do
against the load.
Rod is right, they look at current from the alternator

Every car I've seen, the the alternator, the battery
and the rest of the car are tied to one point

But there is normally more than the one wire
at the the positive terminal of the battery.

Not on any car I've owned or worked on. And more to the point, it's
obviously not needed because cars have worked with the same lead-acid
batteries

They arent the same lead acid batterys, most of the current
ones cant be topped up with extra water when needed.

and alternators with basic voltage regulators for most of the last
century.

We havent used alternators for most of the last century.

and there is no monitor for what current
is going to the battery vs to the car load.

Wrong when there is normally more than the one
wire at the the positive terminal of the battery.

Even if there is an additional wire, explain to us how you
monitor the current in the charging cable with that wire.

With more than one wire, you can see
what the load from the lights etc is.

And you dont even have to do it that way
with modern computer controlled lights now.

And Rod is talking computers,

Because thats what his car has.

But the essence of his question is how cars switch to
trickle charge and AFAIK, the answer is they don't.

The current to the battery does in fact drop
dramatically once the battery is fully charged.

Again, the battery, alternator output and
all the car loads are connected TOGETHER.

Irrelevant to what can be done with
the voltage from the alternator.

so how did cars work prior to the 80s?

The regulator uses the voltage it sees which varys
with the load and the charge of the battery.

And that's all that's needed to keep the battery correctly
charged and working. There was no "trickle charging".

There is in the sense that the current to the battery
drops significantly when the battery is fully charged.
Yes, he didnt word the original very well, but thats
what he always does.

They didn't have a computer didn't monitor anything
other than the voltage regulator maintained a constant
voltage of ~14v while the car was running.

Its more complicated than that with the voltage.

It was that way from the early days and auto batteries charged
fine.

Generators do it differently to alternators and we arent discussing
whether they charged fine or not,

Any other obfuscation you want to throw in?

You never could bull**** your way out of a wet paper bag.

Alternators with voltage regulators have been used with lead
-acid batteries in cars for the better part of the last century.

Wrong, as always.

And the principles with generators are the same.

Wrong, as always. With an alternator you can regulate its output
by varying the exciter current. You cant do that with a generator.

we are discussing what the regulator does when the battery
is fully charged so that it doesnt boil off the water in the
battery. Thats particularly important now that most car
batterys arent refillable with water anymore.

There may be some modern cars where they do monitor the current
going
to the battery, maybe to save energy and increase fuel consumption,

It actually to avoid ****ing the battery by delivering
the same current to the battery when its fully charged.

Xeno and I have correctly described how the basic, widely used
charging
system has worked for decades with the same lead-acid batteries.

They arent the same lead acid batterys.

Rod, you keep spelling *batteries* incorrectly

Wrong, as always.

(just to let you know).

No news to me, boy.

He's probably as old as you.

He isnt.

On Sat, 22 Jun 2019 15:28:21 +0100, trader_4 wrote:

On Friday, June 21, 2019 at 6:48:31 PM UTC-4, wrote:
On Fri, 21 Jun 2019 23:15:21 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know when to
switch to trickle charge? I can understand it noticing a drop in
charging current if the battery is on its own, but what if a random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change? That's determined by the alternator or charger. Let's say the charger/alternator gives out 14.4V initially, to charge the battery quickly. It'll just sit at 14.4V forever, providing the charger can give out enough current to charge the slightly flat battery and power any connected loads. If the battery had no loads connected, it would take a lot less current when it became full, but the voltage would stay the same. If the charger monitored the current it was providing, how does it know if the battery is still charging at 10 amps, or if the battery is full and there's a 10 amp load?

Not really true with anything but the most primative regulator like
you might see on an old outboard. Voltage is regulated somewhere
between 13.x and 14.x, not just reflecting what the alternator can do
against the load.
Rod is right, they look at current from the alternator

Every car I've seen, the the alternator, the battery and the
rest of the car are tied to one point and there is no monitor
for what current is going to the battery vs to the car load.
And Rod is talking computers,
so how did cars work prior to the 80s? They didn't have a computer
didn't monitor anything other than the voltage regulator maintained
a constant voltage of ~14v while the car was running. It was that
way from the early days and auto batteries charged fine.

There may be some modern cars where they do monitor the current going
to the battery, maybe to save energy and increase fuel consumption,
but it's not necessary to keeping the battery charged.

I doubt it saves much energy. Charging a lead acid at 13.8 to 14.4V continuously, wastes **** all power. More likely it can charge at a higher voltage to begin with to make the battery full quickly, then pull back to trickle when needed. Handy if you make a habit of using a lot of accessories like lights when the engine is off then need it charged quickly when you drive for 10 minutes. Or if like me you drive for 100 yards at a time and are using the starter a lot (or have one of those stop start engines). Older cars would run out of battery if you did lots of short journeys, as there was no fast charge.

There is nothing they can do about the load so they don't give a **** about the
lights. The regulator just watches alternator current and cranks up
the voltage to keep it up.

That's rather bizarre. The alternator monitors current? So, what's
the correct current that it's targeting? 2 amps, 20 amps? 70 amps?
The current depends on what loads are on and the alternator doesn't
know that. Seems to me it keeps the system VOLTAGE at ~14V and that
has worked for 100 years.

It would have to monitor the current going into the battery, by having at least two ammeters, or have all the positive wires join somewhere and measure the branch off to the battery.

On Sat, 22 Jun 2019 19:55:03 +0100, Rod Speed wrote:



"Commander Kinsey" wrote in message
news
On Sat, 22 Jun 2019 19:14:07 +0100, Rod Speed
wrote:



"Bod" wrote in message
...
On 22/06/2019 18:02, Rod Speed wrote:


"trader_4" wrote in message
...
On Saturday, June 22, 2019 at 11:45:19 AM UTC-4, Rod Speed wrote:
"trader_4" wrote in message
...
On Friday, June 21, 2019 at 6:48:31 PM UTC-4,
wrote:
On Fri, 21 Jun 2019 23:15:21 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian

wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know
when to
switch to trickle charge? I can understand it noticing a drop
in
charging current if the battery is on its own, but what if a
random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change? That's determined by the
alternator or
charger. Let's say the charger/alternator gives out 14.4V
initially, to
charge the battery quickly. It'll just sit at 14.4V forever,
providing
the charger can give out enough current to charge the slightly
flat
battery and power any connected loads. If the battery had no
loads
connected, it would take a lot less current when it became full,
but the
voltage would stay the same. If the charger monitored the
current it
was providing, how does it know if the battery is still charging
at 10
amps, or if the battery is full and there's a 10 amp load?

Not really true with anything but the most primative regulator
like
you might see on an old outboard. Voltage is regulated somewhere
between 13.x and 14.x, not just reflecting what the alternator can
do
against the load.
Rod is right, they look at current from the alternator

Every car I've seen, the the alternator, the battery
and the rest of the car are tied to one point

But there is normally more than the one wire
at the the positive terminal of the battery.

Not on any car I've owned or worked on. And more to the point, it's
obviously not needed because cars have worked with the same lead-acid
batteries

They arent the same lead acid batterys, most of the current
ones cant be topped up with extra water when needed.

and alternators with basic voltage regulators for most of the last
century.

We havent used alternators for most of the last century.

and there is no monitor for what current
is going to the battery vs to the car load.

Wrong when there is normally more than the one
wire at the the positive terminal of the battery.

Even if there is an additional wire, explain to us how you
monitor the current in the charging cable with that wire.

With more than one wire, you can see
what the load from the lights etc is.

And you dont even have to do it that way
with modern computer controlled lights now.

And Rod is talking computers,

Because thats what his car has.

But the essence of his question is how cars switch to
trickle charge and AFAIK, the answer is they don't.

The current to the battery does in fact drop
dramatically once the battery is fully charged.

Again, the battery, alternator output and
all the car loads are connected TOGETHER.

Irrelevant to what can be done with
the voltage from the alternator.

so how did cars work prior to the 80s?

The regulator uses the voltage it sees which varys
with the load and the charge of the battery.

And that's all that's needed to keep the battery correctly
charged and working. There was no "trickle charging".

There is in the sense that the current to the battery
drops significantly when the battery is fully charged.
Yes, he didnt word the original very well, but thats
what he always does.

They didn't have a computer didn't monitor anything
other than the voltage regulator maintained a constant
voltage of ~14v while the car was running.

Its more complicated than that with the voltage.

It was that way from the early days and auto batteries charged
fine.

Generators do it differently to alternators and we arent discussing
whether they charged fine or not,

Any other obfuscation you want to throw in?

You never could bull**** your way out of a wet paper bag.

Alternators with voltage regulators have been used with lead
-acid batteries in cars for the better part of the last century.

Wrong, as always.

And the principles with generators are the same.

Wrong, as always. With an alternator you can regulate its output
by varying the exciter current. You cant do that with a generator.

we are discussing what the regulator does when the battery
is fully charged so that it doesnt boil off the water in the
battery. Thats particularly important now that most car
batterys arent refillable with water anymore.

There may be some modern cars where they do monitor the current
going
to the battery, maybe to save energy and increase fuel consumption,

It actually to avoid ****ing the battery by delivering
the same current to the battery when its fully charged.

Xeno and I have correctly described how the basic, widely used
charging
system has worked for decades with the same lead-acid batteries.

They arent the same lead acid batterys.

Rod, you keep spelling *batteries* incorrectly

Wrong, as always.

(just to let you know).

No news to me, boy.

He's probably as old as you.

He isnt.

I've met Bod and he's (I'm about to insult him most likely) very very old indeed. I'd have to guess 80 to 90. For some reason I've always assumed you're about 70.

On Sun, 23 Jun 2019 04:14:07 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:


Rod, you keep spelling *batteries* incorrectly

Wrong, as always.

No, he's NOT wrong! But you revealed again that you ARE a sociopathic
asshole, just like that clinically insane Scottish ****** and sociopath!

--
Keema Nam addressing nym-shifting senile Rodent:
"You are now exposed as a liar, as well as an ignorant troll."
"MID: .com"

"Commander Kinsey" wrote in message
news
On Sat, 22 Jun 2019 15:28:21 +0100, trader_4
wrote:

On Friday, June 21, 2019 at 6:48:31 PM UTC-4, wrote:
On Fri, 21 Jun 2019 23:15:21 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian
wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know when
to
switch to trickle charge? I can understand it noticing a drop in
charging current if the battery is on its own, but what if a random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change? That's determined by the alternator or
charger. Let's say the charger/alternator gives out 14.4V initially,
to charge the battery quickly. It'll just sit at 14.4V forever,
providing the charger can give out enough current to charge the
slightly flat battery and power any connected loads. If the battery
had no loads connected, it would take a lot less current when it became
full, but the voltage would stay the same. If the charger monitored
the current it was providing, how does it know if the battery is still
charging at 10 amps, or if the battery is full and there's a 10 amp
load?

Not really true with anything but the most primative regulator like
you might see on an old outboard. Voltage is regulated somewhere
between 13.x and 14.x, not just reflecting what the alternator can do
against the load.
Rod is right, they look at current from the alternator

Every car I've seen, the the alternator, the battery and the
rest of the car are tied to one point and there is no monitor
for what current is going to the battery vs to the car load.
And Rod is talking computers,
so how did cars work prior to the 80s? They didn't have a computer
didn't monitor anything other than the voltage regulator maintained
a constant voltage of ~14v while the car was running. It was that
way from the early days and auto batteries charged fine.

There may be some modern cars where they do monitor the current going
to the battery, maybe to save energy and increase fuel consumption,
but it's not necessary to keeping the battery charged.

I doubt it saves much energy. Charging a lead acid at 13.8 to 14.4V
continuously, wastes **** all power. More likely it can charge at a
higher voltage to begin with to make the battery full quickly, then pull
back to trickle when needed. Handy if you make a habit of using a lot of
accessories like lights when the engine is off then need it charged
quickly when you drive for 10 minutes. Or if like me you drive for 100
yards at a time and are using the starter a lot (or have one of those stop
start engines). Older cars would run out of battery if you did lots of
short journeys, as there was no fast charge.

There is nothing they can do about the load so they don't give a ****
about the
lights. The regulator just watches alternator current and cranks up
the voltage to keep it up.

That's rather bizarre. The alternator monitors current? So, what's
the correct current that it's targeting? 2 amps, 20 amps? 70 amps?
The current depends on what loads are on and the alternator doesn't
know that. Seems to me it keeps the system VOLTAGE at ~14V and that
has worked for 100 years.

It would have to monitor the current going into the battery, by having at
least two ammeters,

Just two cables from the battery positive terminal, one to the alternator
and one
to the rest of the electrical system and measure the voltage drop over
those.

or have all the positive wires join somewhere

They do, the positive terminal of the battery.

and measure the branch off to the battery.

Just subtract the current to the rest of the electrical system
from the current going from the alternator to the battery
terminal. That gives you the current going into the battery.

"Commander Kinsey" wrote in message
news
On Sat, 22 Jun 2019 19:55:03 +0100, Rod Speed
wrote:



"Commander Kinsey" wrote in message
news
On Sat, 22 Jun 2019 19:14:07 +0100, Rod Speed
wrote:



"Bod" wrote in message
...
On 22/06/2019 18:02, Rod Speed wrote:


"trader_4" wrote in message
...
On Saturday, June 22, 2019 at 11:45:19 AM UTC-4, Rod Speed wrote:
"trader_4" wrote in message
...
On Friday, June 21, 2019 at 6:48:31 PM UTC-4,
wrote:
On Fri, 21 Jun 2019 23:15:21 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian

wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator)
know
when to
switch to trickle charge? I can understand it noticing a
drop
in
charging current if the battery is on its own, but what if a
random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change? That's determined by the
alternator or
charger. Let's say the charger/alternator gives out 14.4V
initially, to
charge the battery quickly. It'll just sit at 14.4V forever,

providing
the charger can give out enough current to charge the slightly
flat
battery and power any connected loads. If the battery had no
loads
connected, it would take a lot less current when it became
full,
but the
voltage would stay the same. If the charger monitored the
current it
was providing, how does it know if the battery is still
charging
at 10
amps, or if the battery is full and there's a 10 amp load?

Not really true with anything but the most primative regulator
like
you might see on an old outboard. Voltage is regulated somewhere
between 13.x and 14.x, not just reflecting what the alternator
can
do
against the load.
Rod is right, they look at current from the alternator

Every car I've seen, the the alternator, the battery
and the rest of the car are tied to one point

But there is normally more than the one wire
at the the positive terminal of the battery.

Not on any car I've owned or worked on. And more to the point, it's
obviously not needed because cars have worked with the same
lead-acid
batteries

They arent the same lead acid batterys, most of the current
ones cant be topped up with extra water when needed.

and alternators with basic voltage regulators for most of the last
century.

We havent used alternators for most of the last century.

and there is no monitor for what current
is going to the battery vs to the car load.

Wrong when there is normally more than the one
wire at the the positive terminal of the battery.

Even if there is an additional wire, explain to us how you
monitor the current in the charging cable with that wire.

With more than one wire, you can see
what the load from the lights etc is.

And you dont even have to do it that way
with modern computer controlled lights now.

And Rod is talking computers,

Because thats what his car has.

But the essence of his question is how cars switch to
trickle charge and AFAIK, the answer is they don't.

The current to the battery does in fact drop
dramatically once the battery is fully charged.

Again, the battery, alternator output and
all the car loads are connected TOGETHER.

Irrelevant to what can be done with
the voltage from the alternator.

so how did cars work prior to the 80s?

The regulator uses the voltage it sees which varys
with the load and the charge of the battery.

And that's all that's needed to keep the battery correctly
charged and working. There was no "trickle charging".

There is in the sense that the current to the battery
drops significantly when the battery is fully charged.
Yes, he didnt word the original very well, but thats
what he always does.

They didn't have a computer didn't monitor anything
other than the voltage regulator maintained a constant
voltage of ~14v while the car was running.

Its more complicated than that with the voltage.

It was that way from the early days and auto batteries charged
fine.

Generators do it differently to alternators and we arent discussing
whether they charged fine or not,

Any other obfuscation you want to throw in?

You never could bull**** your way out of a wet paper bag.

Alternators with voltage regulators have been used with lead
-acid batteries in cars for the better part of the last century.

Wrong, as always.

And the principles with generators are the same.

Wrong, as always. With an alternator you can regulate its output
by varying the exciter current. You cant do that with a generator.

we are discussing what the regulator does when the battery
is fully charged so that it doesnt boil off the water in the
battery. Thats particularly important now that most car
batterys arent refillable with water anymore.

There may be some modern cars where they do monitor the current
going
to the battery, maybe to save energy and increase fuel
consumption,

It actually to avoid ****ing the battery by delivering
the same current to the battery when its fully charged.

Xeno and I have correctly described how the basic, widely used
charging
system has worked for decades with the same lead-acid batteries.

They arent the same lead acid batterys.

Rod, you keep spelling *batteries* incorrectly

Wrong, as always.

(just to let you know).

No news to me, boy.

He's probably as old as you.

He isnt.

I've met Bod and he's (I'm about to insult him most likely) very very old
indeed. I'd have to guess 80 to 90.

Thats just the furious drunken grave dancing and flagrant drug abuse.

For some reason I've always assumed you're about 70.

You're still wrong.

On Sun, 23 Jun 2019 04:55:03 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:


He's probably as old as you.

He isnt.

True. There is NOT other senile asshole around as old as you, you clinically
insane 85-year-old senile pest!

--
Sqwertz to Rot Speed:
"This is just a hunch, but I'm betting you're kinda an argumentative
asshole.
MID:

On Sat, 22 Jun 2019 20:08:46 +0100, Rod Speed wrote:



"Commander Kinsey" wrote in message
news
On Sat, 22 Jun 2019 19:55:03 +0100, Rod Speed
wrote:



"Commander Kinsey" wrote in message
news On Sat, 22 Jun 2019 19:14:07 +0100, Rod Speed
wrote:



"Bod" wrote in message
...
On 22/06/2019 18:02, Rod Speed wrote:


"trader_4" wrote in message
...
On Saturday, June 22, 2019 at 11:45:19 AM UTC-4, Rod Speed wrote:
"trader_4" wrote in message
...
On Friday, June 21, 2019 at 6:48:31 PM UTC-4,
wrote:
On Fri, 21 Jun 2019 23:15:21 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian

wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator)
know
when to
switch to trickle charge? I can understand it noticing a
drop
in
charging current if the battery is on its own, but what if a
random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change? That's determined by the
alternator or
charger. Let's say the charger/alternator gives out 14.4V
initially, to
charge the battery quickly. It'll just sit at 14.4V forever,

providing
the charger can give out enough current to charge the slightly
flat
battery and power any connected loads. If the battery had no
loads
connected, it would take a lot less current when it became
full,
but the
voltage would stay the same. If the charger monitored the
current it
was providing, how does it know if the battery is still
charging
at 10
amps, or if the battery is full and there's a 10 amp load?

Not really true with anything but the most primative regulator
like
you might see on an old outboard. Voltage is regulated somewhere
between 13.x and 14.x, not just reflecting what the alternator
can
do
against the load.
Rod is right, they look at current from the alternator

Every car I've seen, the the alternator, the battery
and the rest of the car are tied to one point

But there is normally more than the one wire
at the the positive terminal of the battery.

Not on any car I've owned or worked on. And more to the point, it's
obviously not needed because cars have worked with the same
lead-acid
batteries

They arent the same lead acid batterys, most of the current
ones cant be topped up with extra water when needed.

and alternators with basic voltage regulators for most of the last
century.

We havent used alternators for most of the last century.

and there is no monitor for what current
is going to the battery vs to the car load.

Wrong when there is normally more than the one
wire at the the positive terminal of the battery.

Even if there is an additional wire, explain to us how you
monitor the current in the charging cable with that wire.

With more than one wire, you can see
what the load from the lights etc is.

And you dont even have to do it that way
with modern computer controlled lights now.

And Rod is talking computers,

Because thats what his car has.

But the essence of his question is how cars switch to
trickle charge and AFAIK, the answer is they don't.

The current to the battery does in fact drop
dramatically once the battery is fully charged.

Again, the battery, alternator output and
all the car loads are connected TOGETHER.

Irrelevant to what can be done with
the voltage from the alternator.

so how did cars work prior to the 80s?

The regulator uses the voltage it sees which varys
with the load and the charge of the battery.

And that's all that's needed to keep the battery correctly
charged and working. There was no "trickle charging".

There is in the sense that the current to the battery
drops significantly when the battery is fully charged.
Yes, he didnt word the original very well, but thats
what he always does.

They didn't have a computer didn't monitor anything
other than the voltage regulator maintained a constant
voltage of ~14v while the car was running.

Its more complicated than that with the voltage.

It was that way from the early days and auto batteries charged
fine.

Generators do it differently to alternators and we arent discussing
whether they charged fine or not,

Any other obfuscation you want to throw in?

You never could bull**** your way out of a wet paper bag.

Alternators with voltage regulators have been used with lead
-acid batteries in cars for the better part of the last century..

Wrong, as always.

And the principles with generators are the same.

Wrong, as always. With an alternator you can regulate its output
by varying the exciter current. You cant do that with a generator.

On Saturday, June 22, 2019 at 3:06:28 PM UTC-4, Rod Speed wrote:
"Commander Kinsey" wrote in message
news
On Sat, 22 Jun 2019 15:28:21 +0100, trader_4
wrote:

On Friday, June 21, 2019 at 6:48:31 PM UTC-4, wrote:
On Fri, 21 Jun 2019 23:15:21 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian
wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know when
to
switch to trickle charge? I can understand it noticing a drop in
charging current if the battery is on its own, but what if a random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change? That's determined by the alternator or
charger. Let's say the charger/alternator gives out 14.4V initially,
to charge the battery quickly. It'll just sit at 14.4V forever,
providing the charger can give out enough current to charge the
slightly flat battery and power any connected loads. If the battery
had no loads connected, it would take a lot less current when it became
full, but the voltage would stay the same. If the charger monitored
the current it was providing, how does it know if the battery is still
charging at 10 amps, or if the battery is full and there's a 10 amp
load?

Not really true with anything but the most primative regulator like
you might see on an old outboard. Voltage is regulated somewhere
between 13.x and 14.x, not just reflecting what the alternator can do
against the load.
Rod is right, they look at current from the alternator

Every car I've seen, the the alternator, the battery and the
rest of the car are tied to one point and there is no monitor
for what current is going to the battery vs to the car load.
And Rod is talking computers,
so how did cars work prior to the 80s? They didn't have a computer
didn't monitor anything other than the voltage regulator maintained
a constant voltage of ~14v while the car was running. It was that
way from the early days and auto batteries charged fine.

There may be some modern cars where they do monitor the current going
to the battery, maybe to save energy and increase fuel consumption,
but it's not necessary to keeping the battery charged.

I doubt it saves much energy. Charging a lead acid at 13.8 to 14.4V
continuously, wastes **** all power. More likely it can charge at a
higher voltage to begin with to make the battery full quickly, then pull
back to trickle when needed. Handy if you make a habit of using a lot of
accessories like lights when the engine is off then need it charged
quickly when you drive for 10 minutes. Or if like me you drive for 100
yards at a time and are using the starter a lot (or have one of those stop
start engines). Older cars would run out of battery if you did lots of
short journeys, as there was no fast charge.

There is nothing they can do about the load so they don't give a ****
about the
lights. The regulator just watches alternator current and cranks up
the voltage to keep it up.

That's rather bizarre. The alternator monitors current? So, what's
the correct current that it's targeting? 2 amps, 20 amps? 70 amps?
The current depends on what loads are on and the alternator doesn't
know that. Seems to me it keeps the system VOLTAGE at ~14V and that
has worked for 100 years.

It would have to monitor the current going into the battery, by having at
least two ammeters,

Just two cables from the battery positive terminal, one to the alternator
and one
to the rest of the electrical system and measure the voltage drop over
those.

or have all the positive wires join somewhere

They do, the positive terminal of the battery.

and measure the branch off to the battery.

Just subtract the current to the rest of the electrical system
from the current going from the alternator to the battery
terminal. That gives you the current going into the battery.

When you have an actual credible cite that describes this alleged system, post it. Until then, all you are doing is making crap up on the fly. Like claiming that all cars have more than one wire to the battery positive terminal. Or that cars use the resistance of the large gage cable to measure current. You just pulled that one from your ass, it's rather unlikely for some obvious reasons. But hey, you claim that's how it's done, provide some references.......

....and much better air in here again!

Another typical retarded conversation between our two village idiots,
Birdbrain and Rodent Speed:

Birdbrain: "You beat me to it. Plain sex is boring."

Senile Rodent: "Then **** the cats. That wont be boring."

Birdbrain: "Sell me a de-clawing tool first."

Senile Rodent: "Wont help with the teeth."

Birdbrain: "They've never gone for me with their mouths."

Rodent Speed: "They will if you are stupid enough to try ****ing them."

Birdbrain: "No, they always use claws."

Rodent Speed: "They wont if you try ****ing them. Try it and see."

Message-ID:

On Sat, 22 Jun 2019 20:06:16 +0100, Rod Speed wrote:



"Commander Kinsey" wrote in message
news
On Sat, 22 Jun 2019 15:28:21 +0100, trader_4
wrote:

On Friday, June 21, 2019 at 6:48:31 PM UTC-4, wrote:
On Fri, 21 Jun 2019 23:15:21 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian
wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know when
to
switch to trickle charge? I can understand it noticing a drop in
charging current if the battery is on its own, but what if a random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change? That's determined by the alternator or
charger. Let's say the charger/alternator gives out 14.4V initially,
to charge the battery quickly. It'll just sit at 14.4V forever,
providing the charger can give out enough current to charge the
slightly flat battery and power any connected loads. If the battery
had no loads connected, it would take a lot less current when it became
full, but the voltage would stay the same. If the charger monitored
the current it was providing, how does it know if the battery is still
charging at 10 amps, or if the battery is full and there's a 10 amp
load?

Not really true with anything but the most primative regulator like
you might see on an old outboard. Voltage is regulated somewhere
between 13.x and 14.x, not just reflecting what the alternator can do
against the load.
Rod is right, they look at current from the alternator

Every car I've seen, the the alternator, the battery and the
rest of the car are tied to one point and there is no monitor
for what current is going to the battery vs to the car load.
And Rod is talking computers,
so how did cars work prior to the 80s? They didn't have a computer
didn't monitor anything other than the voltage regulator maintained
a constant voltage of ~14v while the car was running. It was that
way from the early days and auto batteries charged fine.

There may be some modern cars where they do monitor the current going
to the battery, maybe to save energy and increase fuel consumption,
but it's not necessary to keeping the battery charged.

I doubt it saves much energy. Charging a lead acid at 13.8 to 14.4V
continuously, wastes **** all power. More likely it can charge at a
higher voltage to begin with to make the battery full quickly, then pull
back to trickle when needed. Handy if you make a habit of using a lot of
accessories like lights when the engine is off then need it charged
quickly when you drive for 10 minutes. Or if like me you drive for 100
yards at a time and are using the starter a lot (or have one of those stop
start engines). Older cars would run out of battery if you did lots of
short journeys, as there was no fast charge.

There is nothing they can do about the load so they don't give a ****
about the
lights. The regulator just watches alternator current and cranks up
the voltage to keep it up.

That's rather bizarre. The alternator monitors current? So, what's
the correct current that it's targeting? 2 amps, 20 amps? 70 amps?
The current depends on what loads are on and the alternator doesn't
know that. Seems to me it keeps the system VOLTAGE at ~14V and that
has worked for 100 years.

It would have to monitor the current going into the battery, by having at
least two ammeters,

Just two cables from the battery positive terminal, one to the alternator
and one
to the rest of the electrical system and measure the voltage drop over
those.

or have all the positive wires join somewhere

They do, the positive terminal of the battery.

and measure the branch off to the battery.

Just subtract the current to the rest of the electrical system
from the current going from the alternator to the battery
terminal. That gives you the current going into the battery.

Maybe they do that now. But that doesn't help me charging my battery at night with a seperate power supply. I'll just leave it at 13.8V, I don't need a fast charge, I just need it to remain charged as it's full when I get home. No matter what the load, if the terminals of the battery are kept at 13.8V, it should remain full.

On Sun, 23 Jun 2019 05:06:16 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:


Just subtract the current

Just subtract yourself from life finally, you useless 85-year-old senile
cretin!

--
Sqwertz to Rot Speed:
"This is just a hunch, but I'm betting you're kinda an argumentative
asshole.
MID:

Modern car alternators seem to be able to give out a huge amount of current at engine idle speed. I'm sure my friend got his to give out pretty much the full 80 amps without revving the engine. He was powering a small disco on a campsite :-)


On Sat, 22 Jun 2019 11:00:34 +0100, Brian Gaff wrote:

Yes indeed, the nominal output of an alternator can be as high as 15 volts,
but even a fully charged car battery is only 13.8v as far as I know and
these days, I'm sure the direction of current flow and voltages are
monitored very well by the computers. In the old days it was a bit of a
black art just relying on the ability of the alternator or dynamo in the old
bangers.
Normally the output will change due to engine speed, but in alternators
there is a voltage regulator inbuilt to keep the thing pretty nominal and
of course the thing that then suffers is the charging rate, ie its going to
be be slower when its not running very fast. I think if a battery dips below
about 11v outside of starter transients, you have to charge it or get a new
one. This very accurate sensing these days can often mask a battery on its
last legs though, as people tend to ignore warnings if the car still works,
then they leave it a couple of days and it won't start!

Brian

On Sat, 22 Jun 2019 11:11:33 +0100, Rod Speed wrote:

Brian Gaff wrote

Yes indeed, the nominal output of an alternator can be as high as 15
volts, but even a fully charged car battery is only 13.8v as far as I know

They are a bit higher than that just after being charged.

Depends what voltage you were charging them with. 13.8V is the recommended voltage for a continuous charge. 14.4V for fast, and 15V for very fast. But the last two need to be stopped before boil over.

I used to have a home made solar array, with thirty old car batteries in parallel. Bad idea. One of the batteries died - it lost a cell. The other batteries immediately then charged it very quickly as it was 10V and they were 12V, and evaporated the other cells one by one. There was eventually an explosion and the battery was blasted across the garage in several pieces, with a bloody strong smell of rotten eggs.

and these days, I'm sure the direction of current flow and voltages are
monitored very well by the computers. In the old days it was a bit of a
black art just relying on the ability of the alternator or dynamo in the
old bangers.
Normally the output will change due to engine speed, but in alternators
there is a voltage regulator inbuilt to keep the thing pretty nominal
and of course the thing that then suffers is the charging rate, ie its
going to be be slower when its not running very fast. I think if a battery
dips below about 11v outside of starter transients, you have to charge it
or get a new one. This very accurate sensing these days can often mask a
battery on its last legs though, as people tend to ignore warnings if the
car still works, then they leave it a couple of days and it won't start!

Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Rod Speed" wrote in message
...
Commander Kinsey wrote

How does a lead acid battery charger (or car alternator) know when to
switch to trickle charge?

From the current the battery takes.

I can understand it noticing a drop in charging current if the battery
is on its own, but what if a random changing load is connected, as there
is in a running car?

You just look at the current going to the battery. The variably
loads like with lights isnt supplied by the battery when the
engine is running, its supplied by the alternator.

On Sat, 22 Jun 2019 11:55:51 +0100, Mr Pounder Esquire wrote:

Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know when to
switch to trickle charge? I can understand it noticing a drop in
charging current if the battery is on its own, but what if a random
changing load is connected, as there is in a running car?

Asks the unemployable ******/troll with a 20 year old worthless degree and a
stated IQ of 138. Odd that a few years ago your stated IQ was 142.

It has always been 135. And the degree is 22 years old.

On Sat, 22 Jun 2019 20:44:15 +0100, trader_4 wrote:

On Saturday, June 22, 2019 at 3:06:28 PM UTC-4, Rod Speed wrote:
"Commander Kinsey" wrote in message
news
On Sat, 22 Jun 2019 15:28:21 +0100, trader_4
wrote:

On Friday, June 21, 2019 at 6:48:31 PM UTC-4, wrote:
On Fri, 21 Jun 2019 23:15:21 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian
wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know when
to
switch to trickle charge? I can understand it noticing a drop in
charging current if the battery is on its own, but what if a random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change? That's determined by the alternator or
charger. Let's say the charger/alternator gives out 14.4V initially,
to charge the battery quickly. It'll just sit at 14.4V forever,
providing the charger can give out enough current to charge the
slightly flat battery and power any connected loads. If the battery
had no loads connected, it would take a lot less current when it became
full, but the voltage would stay the same. If the charger monitored
the current it was providing, how does it know if the battery is still
charging at 10 amps, or if the battery is full and there's a 10 amp
load?

Not really true with anything but the most primative regulator like
you might see on an old outboard. Voltage is regulated somewhere
between 13.x and 14.x, not just reflecting what the alternator can do
against the load.
Rod is right, they look at current from the alternator

Every car I've seen, the the alternator, the battery and the
rest of the car are tied to one point and there is no monitor
for what current is going to the battery vs to the car load.
And Rod is talking computers,
so how did cars work prior to the 80s? They didn't have a computer
didn't monitor anything other than the voltage regulator maintained
a constant voltage of ~14v while the car was running. It was that
way from the early days and auto batteries charged fine.

There may be some modern cars where they do monitor the current going
to the battery, maybe to save energy and increase fuel consumption,
but it's not necessary to keeping the battery charged.

I doubt it saves much energy. Charging a lead acid at 13.8 to 14.4V
continuously, wastes **** all power. More likely it can charge at a
higher voltage to begin with to make the battery full quickly, then pull
back to trickle when needed. Handy if you make a habit of using a lot of
accessories like lights when the engine is off then need it charged
quickly when you drive for 10 minutes. Or if like me you drive for 100
yards at a time and are using the starter a lot (or have one of those stop
start engines). Older cars would run out of battery if you did lots of
short journeys, as there was no fast charge.

There is nothing they can do about the load so they don't give a ****
about the
lights. The regulator just watches alternator current and cranks up
the voltage to keep it up.

That's rather bizarre. The alternator monitors current? So, what's
the correct current that it's targeting? 2 amps, 20 amps? 70 amps?
The current depends on what loads are on and the alternator doesn't
know that. Seems to me it keeps the system VOLTAGE at ~14V and that
has worked for 100 years.

It would have to monitor the current going into the battery, by having at
least two ammeters,

Just two cables from the battery positive terminal, one to the alternator
and one
to the rest of the electrical system and measure the voltage drop over
those.

or have all the positive wires join somewhere

They do, the positive terminal of the battery.

and measure the branch off to the battery.

Just subtract the current to the rest of the electrical system
from the current going from the alternator to the battery
terminal. That gives you the current going into the battery.

When you have an actual credible cite that describes this alleged system, post it. Until then, all you are doing is making crap up on the fly.

I can believe him, I've observed my car's alternator change from 14.4V to 13.8V after it's been running for a bit, so it must know the battery is full.

Like claiming that all cars have more than one wire to the battery positive terminal.

I've never seen one that doesn't. Usually I see one for the alternator, one for the starter, and one for everything else. Why would you have only one? These are high currents, best to connect things directly.

Or that cars use the resistance of the large gage cable to measure current. You just pulled that one from your ass, it's rather unlikely for some obvious reasons. But hey, you claim that's how it's done, provide some references.......

I do hate it when people say "for obvious reasons" - they are never obvious to anyone else.

That is precisely how you measure current, by a voltage drop across a known resistance. And they certainly don't want to add more resistance to something trying to carry 100s of amps. I guess they could also use an amp clamp, but that would cost more.

On 6/21/19 5:55 PM, Commander Kinsey wrote:

[snip]

I guess charging a car battery with a charger plugged into the house
won't work if you have a load in the car like lights (or in my case a
faulty alarm).* The charger will think the battery is still drawing a
fair current and isn't full, when in fact it's the load eating it up.

I've tried it with an automatic charger. If the load is enough that the
battery won't change within a certain time, the charger stops and
indicates an error.

[snip]

--
Mark Lloyd
http://notstupid.us/

"The deepest sin against the human mind is to believe things without
evidence." -- Thomas Henry Huxley (1825-1895)

On Sat, 22 Jun 2019 22:03:07 +0100, Mark Lloyd wrote:

On 6/21/19 5:55 PM, Commander Kinsey wrote:

[snip]

I guess charging a car battery with a charger plugged into the house
won't work if you have a load in the car like lights (or in my case a
faulty alarm). The charger will think the battery is still drawing a
fair current and isn't full, when in fact it's the load eating it up.

I've tried it with an automatic charger. If the load is enough that the
battery won't change within a certain time, the charger stops and
indicates an error.

That would be useless to me. I've bought a 16 amp 13.8V power supply intended for CB use. Not sure what happens if I try to draw more than 16 amps, but that shouldn't happen. It's short circuit protected, I'd prefer a current limiter but it may just switch off and need reset.

On Sat, 22 Jun 2019 16:45:08 +0100, Rod Speed wrote:



"trader_4" wrote in message
...
On Friday, June 21, 2019 at 6:48:31 PM UTC-4, wrote:
On Fri, 21 Jun 2019 23:15:21 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian
wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know when to
switch to trickle charge? I can understand it noticing a drop in
charging current if the battery is on its own, but what if a random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change? That's determined by the alternator or
charger. Let's say the charger/alternator gives out 14.4V initially, to
charge the battery quickly. It'll just sit at 14.4V forever, providing
the charger can give out enough current to charge the slightly flat
battery and power any connected loads. If the battery had no loads
connected, it would take a lot less current when it became full, but the
voltage would stay the same. If the charger monitored the current it
was providing, how does it know if the battery is still charging at 10
amps, or if the battery is full and there's a 10 amp load?

Not really true with anything but the most primative regulator like
you might see on an old outboard. Voltage is regulated somewhere
between 13.x and 14.x, not just reflecting what the alternator can do
against the load.
Rod is right, they look at current from the alternator

Every car I've seen, the the alternator, the battery
and the rest of the car are tied to one point

But there is normally more than the one wire
at the the positive terminal of the battery.

and there is no monitor for what current
is going to the battery vs to the car load.

Wrong when there is normally more than the one
wire at the the positive terminal of the battery.

And Rod is talking computers,

Because thats what his car has.

so how did cars work prior to the 80s?

The regulator uses the voltage it sees which varys
with the load and the charge of the battery.

That was my original question - on an old car, there is no way for the regulator to tell the difference between the battery still charging at 10 amps and the headlamps being switched on.

They didn't have a computer didn't monitor anything
other than the voltage regulator maintained a constant
voltage of ~14v while the car was running.

Its more complicated than that with the voltage.

It was that way from the early days and auto batteries charged fine.

Generators do it differently to alternators and we arent discussing
whether they charged fine or not, we are discussing what the
regulator does when the battery is fully charged so that it doesnt
boil off the water in the battery. Thats particularly important
now that most car batterys arent refillable with water anymore.

Modern batteries are more resilient actually.

There may be some modern cars where they do monitor the current going
to the battery, maybe to save energy and increase fuel consumption,

It actually to avoid ****ing the battery by delivering
the same current to the battery when its fully charged.

Wouldn't have to if they just charged at 13.8V, but I assume they're trying to do a fast charge first.

but it's not necessary to keeping the battery charged.

That isnt what is being discussed either.

There is nothing they can do about the load so they don't
give a **** about the lights. The regulator just watches
alternator current and cranks up the voltage to keep it up.

That's rather bizarre. The alternator monitors current? So, what's
the correct current that it's targeting? 2 amps, 20 amps? 70 amps?
The current depends on what loads are on and the alternator doesn't
know that. Seems to me it keeps the system VOLTAGE at ~14V

No it doesnt. Doing that would overcharge a fully charged battery.

and that has worked for 100 years.

Wrong again, generators do it differently to alternators.

On Sat, 22 Jun 2019 01:17:29 +0100, wrote:

On Fri, 21 Jun 2019 23:55:31 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 23:48:01 +0100, wrote:

On Fri, 21 Jun 2019 23:15:21 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know when to
switch to trickle charge? I can understand it noticing a drop in
charging current if the battery is on its own, but what if a random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change? That's determined by the alternator or charger. Let's say the charger/alternator gives out 14.4V initially, to charge the battery quickly. It'll just sit at 14.4V forever, providing the charger can give out enough current to charge the slightly flat battery and power any connected loads. If the battery had no loads connected, it would take a lot less current when it became full, but the voltage would stay the same. If the charger monitored the current it was providing, how does it know if the battery is still charging at 10 amps, or if the battery is full and there's a 10 amp load?

Not really true with anything but the most primative regulator like
you might see on an old outboard. Voltage is regulated somewhere
between 13.x and 14.x, not just reflecting what the alternator can do
against the load.
Rod is right, they look at current from the alternator There is
nothing they can do about the load so they don't give a **** about the
lights. The regulator just watches alternator current and cranks up
the voltage to keep it up. When current drops off it is either because
there is less load or because the battery is taking less of a charge.
That is when the voltage ramps down.
If current gets really low, like the battery is charged and there is
not much load they hit the bottom of the range ... essentially a
trickle charger that is also running the radio and heater fan.

Take this situation: You start your car with the battery 3/4s full. The alternator provides a high voltage and charges it quickly. It's dark and cold, you have demisters, lights, etc on. How does the alternator know when the battery is full? As current will continue to be taken from it to power all those loads.

As for a smart charger, usually the voltage is all they need to know.
When the voltage drop across the battery starts to rise. it indicates
the battery is charging and at a certain point they either turn off or
turn to trickle.
Different batteries have different "fully charged" voltage levels so
they usually have a switch for different types . (deep cycle, AGM etc)

I guess charging a car battery with a charger plugged into the house won't work if you have a load in the car like lights (or in my case a faulty alarm). The charger will think the battery is still drawing a fair current and isn't full, when in fact it's the load eating it up.

Plug in chargers are voltage regulated so that load would pull the
voltage down and the charger would try to bring it up. Once the
battery was charged the charger would either see a higher voltage and
ramp down or it would stay there at. what it could drive.

No, if you charge a battery with no load, the charger will sit at 14.4V (provided it can give enough current to do that) until the battery drew little current, then it would back off to 13.8V.

But with a load, the charger thinks the battery is still charging, when in fact it's the load taking that current. So it will stay at 14.4V forever and **** the battery.

That is
probably a good reason to turn all that crap off when you are charging
a battery off line

I don't have anything deliberately loading it.

and you might want to take the negative lead to the
car loose if you have too much residual load.

Too much hassle. Anyway if I was going to do that, which I used to, I wouldn't even need a charger as the battery would never go flat.

Maybe you could figure
out what was killing the battery in the first place then.

I know it's the alarm, as it still does it with every damn fuse pulled out. The alarm is hidden away and difficult to disconnect, to stop thieves doing so.

On Sat, 22 Jun 2019 16:03:07 -0500, Mark Lloyd, another absolutely brain
dead troll-feeding senile idiot, blathered again:


I've tried it with an automatic charger. If the load is enough that the
battery won't change within a certain time, the charger stops and
indicates an error.

I charge YOU with being an absolutely brain-dead, troll-feeding, senile
asshole!

On Sat, 22 Jun 2019 18:02:30 +0100, Rod Speed wrote:



"trader_4" wrote in message
...
On Saturday, June 22, 2019 at 11:45:19 AM UTC-4, Rod Speed wrote:
"trader_4" wrote in message
...
On Friday, June 21, 2019 at 6:48:31 PM UTC-4, wrote:
On Fri, 21 Jun 2019 23:15:21 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian

wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know when
to
switch to trickle charge? I can understand it noticing a drop in
charging current if the battery is on its own, but what if a
random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change? That's determined by the alternator or
charger. Let's say the charger/alternator gives out 14.4V initially,
to
charge the battery quickly. It'll just sit at 14.4V forever,
providing
the charger can give out enough current to charge the slightly flat
battery and power any connected loads. If the battery had no loads
connected, it would take a lot less current when it became full, but
the
voltage would stay the same. If the charger monitored the current it
was providing, how does it know if the battery is still charging at
10
amps, or if the battery is full and there's a 10 amp load?

Not really true with anything but the most primative regulator like
you might see on an old outboard. Voltage is regulated somewhere
between 13.x and 14.x, not just reflecting what the alternator can do
against the load.
Rod is right, they look at current from the alternator

Every car I've seen, the the alternator, the battery
and the rest of the car are tied to one point

But there is normally more than the one wire
at the the positive terminal of the battery.

Not on any car I've owned or worked on. And more to the point, it's
obviously not needed because cars have worked with the same lead-acid
batteries

They arent the same lead acid batterys, most of the current
ones cant be topped up with extra water when needed.

and alternators with basic voltage regulators for most of the last
century.

We havent used alternators for most of the last century.

and there is no monitor for what current
is going to the battery vs to the car load.

Wrong when there is normally more than the one
wire at the the positive terminal of the battery.

Even if there is an additional wire, explain to us how you
monitor the current in the charging cable with that wire.

With more than one wire, you can see
what the load from the lights etc is.

And you dont even have to do it that way
with modern computer controlled lights now.

I doubt it knows about everything, like how much power you're using from the cigarette lighter socket etc. Easier to just measure the total load in one go, than trying to add up precise currents it thinks the wipers might be using etc.

And Rod is talking computers,

Because thats what his car has.

But the essence of his question is how cars switch to
trickle charge and AFAIK, the answer is they don't.

The current to the battery does in fact drop
dramatically once the battery is fully charged.

The chemistry of the battery sees to that itself, but it's better for the battery to lower the voltage from 14.4 to 13.8 when it's full. It's not as easy as a lithium cell where you just give it 4.2V.

On Sat, 22 Jun 2019 17:03:08 +0100, TMS320 wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know when to
switch to trickle charge?

It doesn't.

Mine does, if I start my car when the battery is say 80% full, the voltage will be 14.4V. After a while, something causes that voltage to drop to 13.8, because something knows the battery is full and should no longer be charged at a high rate.

I can understand it noticing a drop in
charging current if the battery is on its own, but what if a random
changing load is connected, as there is in a running car?

Ohm's law.

Explain how an alternator or charger can use ohm's law to distinguish between:
1) A car battery which is full, with a load of 10 amps connected to it, like two headlights.
2) A car battery with no load, which is not full yet and draws 10 amps for the charge.

On Sat, 22 Jun 2019 00:57:57 +0100, Rod Speed wrote:



"Commander Kinsey" wrote in message
news
On Fri, 21 Jun 2019 23:57:52 +0100, Rod Speed
wrote:



"Commander Kinsey" wrote in message
news On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian
wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know when to
switch to trickle charge? I can understand it noticing a drop in
charging current if the battery is on its own, but what if a random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change?

That's the way batterys work, the battery voltage does change as its
charged.

That's determined by the alternator or charger.

Nope.

Yip.

Nope.

I can put any voltage I like across a battery's terminals.

Nope.

I can if the charger / power supply is powerful enough.

The battery then chooses how much current is drawn.

And that current changes depending on the how charged the battery is.

Correct, it's the current it checks.

Let's say the charger/alternator gives out 14.4V initially, to charge
the
battery quickly. It'll just sit at 14.4V forever, providing the charger
can give out enough current to charge the slightly flat battery and
power
any connected loads.

Its more complicated than that with the current going to the battery and
the
battery is charged.

If the battery had no loads connected, it would take a lot less current
when it became full, but the voltage would stay the same.

No it doesn't even with a very crude battery charger.

For example, I'm currently keeping my car's battery topped up with a bench
supply overnight. It's set to 13.8V, with a current limiter only to
prevent overloading the supply.

It actually specify the current being supplied.

No, it LIMITS the current. I set 13.8V, 2.5A. It will back off if either is exceeded.

The voltage stays at 13.8V all the time, sometimes 100mA is drawn,
sometimes up to 4A. The only way I or the supply can tell the battery is
full, is by the current dropping to 100mA. But it's actually always full,
as when 4A is drawn, that's going to a load.

What load ? There no load with a battery being charged with a bench supply.

The faulty frog car with the dodgy alarm.

On Sat, 22 Jun 2019 11:41:15 +0100, Xeno wrote:

On 22/6/19 7:58 pm, Rod Speed wrote:


"Xeno" wrote in message
...
On 22/6/19 9:57 am, Rod Speed wrote:


"Commander Kinsey" wrote in message
news On Fri, 21 Jun 2019 23:57:52 +0100, Rod Speed
wrote:



"Commander Kinsey" wrote in message
news On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian

wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know
when to
switch to trickle charge? I can understand it noticing a drop in
charging current if the battery is on its own, but what if a random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change?

That's the way batterys work, the battery voltage does change as its
charged.

That's determined by the alternator or charger.

Nope.

Yip.

Nope.

I can put any voltage I like across a battery's terminals.

Nope.

The battery then chooses how much current is drawn.

And that current changes depending on the how charged the battery is.

Let's say the charger/alternator gives out 14.4V initially, to
charge the
battery quickly. It'll just sit at 14.4V forever, providing the
charger
can give out enough current to charge the slightly flat battery
and power
any connected loads.

Its more complicated than that with the current going to the
battery and the
battery is charged.

If the battery had no loads connected, it would take a lot less
current
when it became full, but the voltage would stay the same.

No it doesn't even with a very crude battery charger.

For example, I'm currently keeping my car's battery topped up with a
bench supply overnight. It's set to 13.8V, with a current limiter
only to prevent overloading the supply.

It actually specify the current being supplied.

The voltage stays at 13.8V all the time, sometimes 100mA is drawn,
sometimes up to 4A. The only way I or the supply can tell the
battery is full, is by the current dropping to 100mA. But it's
actually always full, as when 4A is drawn, that's going to a load.

What load ? There no load with a battery being charged with a bench
supply.

Correction

Nope.

the *battery* is the *load*.

Not when the battery is fully charges and is being charged
with a bench supply that is delivering 4A to the battery.

Take the case of an alternator charging a battery at ~4 amps. The
battery is the load and it also provides, as part of that function, the
reference *voltage* that the alternator *must have* in order to control
the output.

I believe the reason Rod mentioned load as being seperate to the battery is this thread is about my car, with a fault that draws current from the battery, and it's also connected to a bench supply. In this situation, we refer to "load" as the faulty alarm system. I originally asked how an alternator could distinguish between the battery charging, and a load such as your headlamps being on.

In the process of being charged it is using electric current. That
makes it the load.

See above.

What happens to the charger when you disconnect the power with the
battery connected? It should, if designed correctly, shut down since it
no longer sees a load. Otherwise it may destroy itself.

Bull****. You're telling me that a bench supply with a battery on the output and no 240V input will blow up if it doesn't shut down? Wrong. Absolutely wrong. The output end of the supply (which probably ends with smoothing capacitors) is just kept at the normal output voltage by the battery.

Even when it is fully charged it will still take a trickle charge

4A isnt a trickle charge.

That depends entirely on the amp hour rating of the battery.
Also, my bench charger will start off at 4 amps, its maximum capacity.
As the battery becomes charged, that current will drop down to *1 amp*
and, from that point, it will maintain a *trickle charge*.

How ****ing big is that battery?! When I charge a 60Ah lead acid at 13.8V, it drops to about 150mA when full.

From Wikipedia;
For lead-acid batteries under no load float charging (such as
in SLI batteries), trickle charging happens naturally at the
end-of-charge, when the lead-acid battery internal resistance
to the charging current increases enough to reduce additional
charging current to a trickle, hence the name. In such cases,
the trickle charging equals the energy expended by the
lead-acid battery splitting the water in the electrolyte into
hydrogen and oxygen gases

Trouble is you might want to do a bulk charge first, at 14.4V.

The car alternator regulator is no different. It sees the battery as a
load, determines the voltage reference and pumps up its output.

All it can do is supply a certain voltage. 13.8V is safe. If it uses 14.4V or higher, it has to know when to back off to 13.8. It cannot do that if there is an external current draw like headlamp, as it won't know if they're switched on, or if the battery is drawing that current.

When the
regulator sees the battery voltage at the peak setpoint,

You can't tell a battery is full by voltage. You can only tell by it drawing less current. The voltage is determined by the charger.

it too will
drop the current to a trickle.

Actually it drops the voltage, to 13.8. I used to have a solar battery regulator which had very detailed instructions saying how it worked. It took the voltage of the solar cells and altered it up or down a bit to suit the battery condition.

If you add a load, say by turning
headlights on, that is in *parallel* to the battery and it will drop the
system voltage down a tad. The regulator will see that and pump up the
output current appropriately. The current will apportion itself to the
*two* loads as appropriate to their individual internal resistances.

But it can't tell the difference between current going to the lights and to the battery.

On Sat, 22 Jun 2019 16:29:26 +0100, trader_4 wrote:

On Saturday, June 22, 2019 at 6:41:22 AM UTC-4, Xeno wrote:
On 22/6/19 7:58 pm, Rod Speed wrote:


"Xeno" wrote in message
...
On 22/6/19 9:57 am, Rod Speed wrote:


"Commander Kinsey" wrote in message
news On Fri, 21 Jun 2019 23:57:52 +0100, Rod Speed
wrote:



"Commander Kinsey" wrote in message
news On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian

wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know
when to
switch to trickle charge? I can understand it noticing a drop in
charging current if the battery is on its own, but what if a random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change?

That's the way batterys work, the battery voltage does change as its
charged.

That's determined by the alternator or charger.

Nope.

Yip.

Nope.

I can put any voltage I like across a battery's terminals.

Nope.

The battery then chooses how much current is drawn.

And that current changes depending on the how charged the battery is.

Let's say the charger/alternator gives out 14.4V initially, to
charge the
battery quickly. It'll just sit at 14.4V forever, providing the
charger
can give out enough current to charge the slightly flat battery
and power
any connected loads.

Its more complicated than that with the current going to the
battery and the
battery is charged.

If the battery had no loads connected, it would take a lot less
current
when it became full, but the voltage would stay the same.

No it doesn't even with a very crude battery charger.

For example, I'm currently keeping my car's battery topped up with a
bench supply overnight. It's set to 13.8V, with a current limiter
only to prevent overloading the supply.

It actually specify the current being supplied.

The voltage stays at 13.8V all the time, sometimes 100mA is drawn,
sometimes up to 4A. The only way I or the supply can tell the
battery is full, is by the current dropping to 100mA. But it's
actually always full, as when 4A is drawn, that's going to a load.

What load ? There no load with a battery being charged with a bench
supply.

Correction

Nope.

the *battery* is the *load*.

Not when the battery is fully charges and is being charged
with a bench supply that is delivering 4A to the battery.

Take the case of an alternator charging a battery at ~4 amps. The
battery is the load and it also provides, as part of that function, the
reference *voltage* that the alternator *must have* in order to control
the output.

+1
You are 100% correct.

You do realize who you are dealing with here, right? Here is some of
the other BS he posted and then just continued to lie about, refuse
to acknowledge it was all wrong:

How can one dope be wrong on so many things?



The 737 MCAS doesn't rely on just one AOA sensor (It does)

The FAA would never approve that design (They did)

[snip]

You've already posted all that ****e. Repeating yourself is a sign of illness.

On Sat, 22 Jun 2019 16:16:30 +0100, trader_4 wrote:

On Friday, June 21, 2019 at 7:33:38 PM UTC-4, Commander Kinsey wrote:
On Fri, 21 Jun 2019 23:57:52 +0100, Rod Speed wrote:



"Commander Kinsey" wrote in message
news On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian
wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know when to
switch to trickle charge? I can understand it noticing a drop in
charging current if the battery is on its own, but what if a random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change?

That's the way batterys work, the battery voltage does change as its
charged.

That's determined by the alternator or charger.

Nope.

Yip. I can put any voltage I like across a battery's terminals. The battery then chooses how much current is drawn.

Correct, within reason and the physical limits of the battery. A battery
looks like an ideal voltage source connected in series with a low value
resistor.





Let's say the charger/alternator gives out 14.4V initially, to charge the
battery quickly. It'll just sit at 14.4V forever, providing the charger
can give out enough current to charge the slightly flat battery and power
any connected loads.

Its more complicated than that with the current going to the battery and the
battery is charged.

If the battery had no loads connected, it would take a lot less current
when it became full, but the voltage would stay the same.

No it doesn't even with a very crude battery charger.

For example, I'm currently keeping my car's battery topped up with a bench supply overnight. It's set to 13.8V, with a current limiter only to prevent overloading the supply. The voltage stays at 13.8V all the time, sometimes 100mA is drawn, sometimes up to 4A. The only way I or the supply can tell the battery is full, is by the current dropping to 100mA. But it's actually always full, as when 4A is drawn, that's going to a load.

If the charger monitored the current it was providing, how does it know if
the battery is still charging at 10 amps, or if the battery is full and
there's a 10 amp load?

By checking the current actually being delivered to the battery.

I guess that may be true, if the car's computer has two ammeters and subtracts one from the other. But AFAIK, the alternator regulator only works by it's own current sensor. And that current could be going into the battery, or past it to the loads.

The voltage regulator actually senses VOLTAGE, which is why it;s called
a voltage regulator.

No it doesn't. It keeps the voltage at the correct level for charging, which is 14.4V for fast charge and 13.8V for trickle charge. It senses a drop in current to tell when the battery is full.

But I agree, I have yet to see a car where the
computer is monitoring the current flow into the battery. And even if
some very modern cars do,

Mine is 2002, and French, so subtract a few years. Something changes the regulator from 14.4V to 13.8V when it knows the battery is full. here has to be a sensor outside the alternator and regulator so it knows the battery is full. Because if I had the lights on, it would see that as a the same as the battery still charging

it doesn't change the fact that 99.9% of cars
have worked fine with the same batteries and just a simple voltage
regulator. And that seemed to be your question, what is required to
keep a battery properly charged and how it works. Obviously no complicated
computers, current monitoring, etc is required as evidenced by billions
of cars.

They probably either just charged at 13.8V (which is why older cars got flat batteries, they never did a fast boost charge after starting), or they charged at 14.4V and assumed a battery wouldn't mind that as your car ain't running 24/7, or did a compromise and charged at about 14V. But stick a battery on 14.4V on your bench forever and it will burn out in a few months.

On 23/6/19 1:29 am, trader_4 wrote:
On Saturday, June 22, 2019 at 5:58:46 AM UTC-4, Rod Speed wrote:
"Xeno" wrote in message
...
On 22/6/19 9:57 am, Rod Speed wrote:


"Commander Kinsey" wrote in message
news On Fri, 21 Jun 2019 23:57:52 +0100, Rod Speed
wrote:



"Commander Kinsey" wrote in message
news On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian

wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know when
to
switch to trickle charge? I can understand it noticing a drop in
charging current if the battery is on its own, but what if a random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change?

That's the way batterys work, the battery voltage does change as its
charged.

That's determined by the alternator or charger.

Nope.

Yip.

Nope.

I can put any voltage I like across a battery's terminals.

Nope.

The battery then chooses how much current is drawn.

And that current changes depending on the how charged the battery is.

Let's say the charger/alternator gives out 14.4V initially, to charge
the
battery quickly. It'll just sit at 14.4V forever, providing the
charger
can give out enough current to charge the slightly flat battery and
power
any connected loads.

Its more complicated than that with the current going to the battery
and the
battery is charged.

If the battery had no loads connected, it would take a lot less
current
when it became full, but the voltage would stay the same.

No it doesn't even with a very crude battery charger.

For example, I'm currently keeping my car's battery topped up with a
bench supply overnight. It's set to 13.8V, with a current limiter only
to prevent overloading the supply.

It actually specify the current being supplied.

The voltage stays at 13.8V all the time, sometimes 100mA is drawn,
sometimes up to 4A. The only way I or the supply can tell the battery
is full, is by the current dropping to 100mA. But it's actually always
full, as when 4A is drawn, that's going to a load.

What load ? There no load with a battery being charged with a bench
supply.

Correction

Nope.

the *battery* is the *load*.

Not when the battery is fully charges and is being charged
with a bench supply that is delivering 4A to the battery.

Well of course the battery is the *load* in his simple example.
The power supply is the power source, the battery is the load
and 4A is being delivered to the load.

Pure logic. I think there's a dead short in Rod's brain if he can't see
that.



In the process of being charged it is using electric current. That makes
it the load.

See above.

See even an elementary school level explanation of electric circuits.



--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)

"Commander Kinsey" wrote in message
news
On Sat, 22 Jun 2019 20:08:46 +0100, Rod Speed
wrote:



"Commander Kinsey" wrote in message
news
On Sat, 22 Jun 2019 19:55:03 +0100, Rod Speed
wrote:



"Commander Kinsey" wrote in message
news On Sat, 22 Jun 2019 19:14:07 +0100, Rod Speed

wrote:



"Bod" wrote in message
...
On 22/06/2019 18:02, Rod Speed wrote:


"trader_4" wrote in message
...
On Saturday, June 22, 2019 at 11:45:19 AM UTC-4, Rod Speed wrote:
"trader_4" wrote in message
...
On Friday, June 21, 2019 at 6:48:31 PM UTC-4,
wrote:
On Fri, 21 Jun 2019 23:15:21 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian

wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator)
know
when to
switch to trickle charge? I can understand it noticing a
drop
in
charging current if the battery is on its own, but what if
a
random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change? That's determined by the
alternator or
charger. Let's say the charger/alternator gives out 14.4V
initially, to
charge the battery quickly. It'll just sit at 14.4V forever,

providing
the charger can give out enough current to charge the
slightly
flat
battery and power any connected loads. If the battery had no
loads
connected, it would take a lot less current when it became
full,
but the
voltage would stay the same. If the charger monitored the
current it
was providing, how does it know if the battery is still
charging
at 10
amps, or if the battery is full and there's a 10 amp load?

Not really true with anything but the most primative regulator
like
you might see on an old outboard. Voltage is regulated
somewhere
between 13.x and 14.x, not just reflecting what the alternator
can
do
against the load.
Rod is right, they look at current from the alternator

Every car I've seen, the the alternator, the battery
and the rest of the car are tied to one point

But there is normally more than the one wire
at the the positive terminal of the battery.

Not on any car I've owned or worked on. And more to the point,
it's
obviously not needed because cars have worked with the same
lead-acid
batteries

They arent the same lead acid batterys, most of the current
ones cant be topped up with extra water when needed.

and alternators with basic voltage regulators for most of the last
century.

We havent used alternators for most of the last century.

and there is no monitor for what current
is going to the battery vs to the car load.

Wrong when there is normally more than the one
wire at the the positive terminal of the battery.

Even if there is an additional wire, explain to us how you
monitor the current in the charging cable with that wire.

With more than one wire, you can see
what the load from the lights etc is.

And you dont even have to do it that way
with modern computer controlled lights now.

And Rod is talking computers,

Because thats what his car has.

But the essence of his question is how cars switch to
trickle charge and AFAIK, the answer is they don't.

The current to the battery does in fact drop
dramatically once the battery is fully charged.

Again, the battery, alternator output and
all the car loads are connected TOGETHER.

Irrelevant to what can be done with
the voltage from the alternator.

so how did cars work prior to the 80s?

The regulator uses the voltage it sees which varys
with the load and the charge of the battery.

And that's all that's needed to keep the battery correctly
charged and working. There was no "trickle charging".

There is in the sense that the current to the battery
drops significantly when the battery is fully charged.
Yes, he didnt word the original very well, but thats
what he always does.

They didn't have a computer didn't monitor anything
other than the voltage regulator maintained a constant
voltage of ~14v while the car was running.

Its more complicated than that with the voltage.

It was that way from the early days and auto batteries charged
fine.

Generators do it differently to alternators and we arent
discussing
whether they charged fine or not,

Any other obfuscation you want to throw in?

You never could bull**** your way out of a wet paper bag.

Alternators with voltage regulators have been used with lead
-acid batteries in cars for the better part of the last century.

Wrong, as always.

And the principles with generators are the same.

Wrong, as always. With an alternator you can regulate its output
by varying the exciter current. You cant do that with a generator.

we are discussing what the regulator does when the battery
is fully charged so that it doesnt boil off the water in the
battery. Thats particularly important now that most car
batterys arent refillable with water anymore.

There may be some modern cars where they do monitor the current
going
to the battery, maybe to save energy and increase fuel
consumption,

It actually to avoid ****ing the battery by delivering
the same current to the battery when its fully charged.

Xeno and I have correctly described how the basic, widely used
charging
system has worked for decades with the same lead-acid batteries.

They arent the same lead acid batterys.

Rod, you keep spelling *batteries* incorrectly

Wrong, as always.

(just to let you know).

No news to me, boy.

He's probably as old as you.

He isnt.

I've met Bod and he's (I'm about to insult him most likely) very very
old
indeed. I'd have to guess 80 to 90.

Thats just the furious drunken grave dancing and flagrant drug abuse.

Smoking does make your face more wrinkly, but I'm sure he told me his age
once.

But you have no way of knowing whether he lied to cover up
the furious drunken grave dancing and flagrant drug abuse.

For some reason I've always assumed you're about 70.

You're still wrong.

What is your age then?

If I told you that I'd have to kill you.

And back on topic, I just bought a 16 amp 13.8V power supply, that ought
to keep the bloody frog car charged up.

It would have been better to get a proper intelligent
charger or one of those power banks to start the car.
And to fix the discharging of the battery overnight. I
just dont believe that all the owners of that steaming
turd with wheels are physically charging the car overnight.

It's currently maxing out my 2.5A supply all night, and still not starting
in the morning.

Fark, thats some fault which should be hard to find.

Some gutless drug crazed drunken diseased ****wit thats
actually stupid enough to believe that that fool Raygun
actually won the cold war, desperately cowering behind
trader_4 spewed the **** youd
expect from a desperately cowering drunken drug crazed
diseased ****wit thats actually stupid enough to believe
that that fool Raygun won the cold war.

"Commander Kinsey" wrote in message
news
On Sat, 22 Jun 2019 20:06:16 +0100, Rod Speed
wrote:



"Commander Kinsey" wrote in message
news
On Sat, 22 Jun 2019 15:28:21 +0100, trader_4
wrote:

On Friday, June 21, 2019 at 6:48:31 PM UTC-4, wrote:
On Fri, 21 Jun 2019 23:15:21 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian

wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know when
to
switch to trickle charge? I can understand it noticing a drop in
charging current if the battery is on its own, but what if a
random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change? That's determined by the alternator or
charger. Let's say the charger/alternator gives out 14.4V initially,
to charge the battery quickly. It'll just sit at 14.4V forever,
providing the charger can give out enough current to charge the
slightly flat battery and power any connected loads. If the battery
had no loads connected, it would take a lot less current when it
became
full, but the voltage would stay the same. If the charger monitored
the current it was providing, how does it know if the battery is
still
charging at 10 amps, or if the battery is full and there's a 10 amp
load?

Not really true with anything but the most primative regulator like
you might see on an old outboard. Voltage is regulated somewhere
between 13.x and 14.x, not just reflecting what the alternator can do
against the load.
Rod is right, they look at current from the alternator

Every car I've seen, the the alternator, the battery and the
rest of the car are tied to one point and there is no monitor
for what current is going to the battery vs to the car load.
And Rod is talking computers,
so how did cars work prior to the 80s? They didn't have a computer
didn't monitor anything other than the voltage regulator maintained
a constant voltage of ~14v while the car was running. It was that
way from the early days and auto batteries charged fine.

There may be some modern cars where they do monitor the current going
to the battery, maybe to save energy and increase fuel consumption,
but it's not necessary to keeping the battery charged.

I doubt it saves much energy. Charging a lead acid at 13.8 to 14.4V
continuously, wastes **** all power. More likely it can charge at a
higher voltage to begin with to make the battery full quickly, then pull
back to trickle when needed. Handy if you make a habit of using a lot
of
accessories like lights when the engine is off then need it charged
quickly when you drive for 10 minutes. Or if like me you drive for 100
yards at a time and are using the starter a lot (or have one of those
stop
start engines). Older cars would run out of battery if you did lots of
short journeys, as there was no fast charge.

There is nothing they can do about the load so they don't give a ****
about the
lights. The regulator just watches alternator current and cranks up
the voltage to keep it up.

That's rather bizarre. The alternator monitors current? So, what's
the correct current that it's targeting? 2 amps, 20 amps? 70 amps?
The current depends on what loads are on and the alternator doesn't
know that. Seems to me it keeps the system VOLTAGE at ~14V and that
has worked for 100 years.

It would have to monitor the current going into the battery, by having
at
least two ammeters,

Just two cables from the battery positive terminal, one to the alternator
and one
to the rest of the electrical system and measure the voltage drop over
those.

or have all the positive wires join somewhere

They do, the positive terminal of the battery.

and measure the branch off to the battery.

Just subtract the current to the rest of the electrical system
from the current going from the alternator to the battery
terminal. That gives you the current going into the battery.

Maybe they do that now. But that doesn't help me charging my battery at
night with a seperate power supply.

Yep, you should be working out where that massive
fault is and fixing it. Even using one of those power
banks to start the car with the car battery flat isnt
much of a solution because lead acid batterys hate
being flat and you will be going thru battery too
fast with the battery flattened every night.

One crude approach would be to get one of those
battery disconnectors used in RVs and disconnect
the battery every night.

I'll just leave it at 13.8V,

Remains to be seen if that will **** the battery.

I don't need a fast charge, I just need it to remain charged as it's full
when I get home.

A battery disonnector would world
much better and is easier to use too.

No matter what the load, if the terminals of the battery are kept at
13.8V, it should remain full.

So would a battery disconnector and is easier to use.

Commander Kinsey wrote
Rod Speed wrote
Brian Gaff wrote

Yes indeed, the nominal output of an alternator can be as high as 15
volts, but even a fully charged car battery is only 13.8v as far as I
know

They are a bit higher than that just after being charged.

Depends what voltage you were charging them with.

We're discussing cars.

13.8V is the recommended voltage for a continuous charge.

That's wrong too.

14.4V for fast, and 15V for very fast.

And so is that.

But the last two need to be stopped before boil over.

I used to have a home made solar array, with thirty old car batteries in
parallel. Bad idea. One of the batteries died - it lost a cell. The
other batteries immediately then charged it very quickly as it was 10V and
they were 12V, and evaporated the other cells one by one.

Trivially easy to avoid that.

There was eventually an explosion

That was the hydrogen you stupidly didn't get rid of.

and the battery was blasted across the garage in several pieces, with a
bloody strong smell of rotten eggs.

and these days, I'm sure the direction of current flow and voltages are
monitored very well by the computers. In the old days it was a bit of a
black art just relying on the ability of the alternator or dynamo in the
old bangers.
Normally the output will change due to engine speed, but in alternators
there is a voltage regulator inbuilt to keep the thing pretty nominal
and of course the thing that then suffers is the charging rate, ie its
going to be be slower when its not running very fast. I think if a
battery
dips below about 11v outside of starter transients, you have to charge
it
or get a new one. This very accurate sensing these days can often mask
a
battery on its last legs though, as people tend to ignore warnings if
the
car still works, then they leave it a couple of days and it won't start!

Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Rod Speed" wrote in message
...
Commander Kinsey wrote

How does a lead acid battery charger (or car alternator) know when to
switch to trickle charge?

From the current the battery takes.

I can understand it noticing a drop in charging current if the battery
is on its own, but what if a random changing load is connected, as
there
is in a running car?

You just look at the current going to the battery. The variably
loads like with lights isnt supplied by the battery when the
engine is running, its supplied by the alternator.

"Commander Kinsey" wrote in message
news
On Sat, 22 Jun 2019 16:45:08 +0100, Rod Speed
wrote:



"trader_4" wrote in message
...
On Friday, June 21, 2019 at 6:48:31 PM UTC-4, wrote:
On Fri, 21 Jun 2019 23:15:21 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian

wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know when
to
switch to trickle charge? I can understand it noticing a drop in
charging current if the battery is on its own, but what if a random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change? That's determined by the alternator or
charger. Let's say the charger/alternator gives out 14.4V initially,
to
charge the battery quickly. It'll just sit at 14.4V forever,
providing
the charger can give out enough current to charge the slightly flat
battery and power any connected loads. If the battery had no loads
connected, it would take a lot less current when it became full, but
the
voltage would stay the same. If the charger monitored the current it
was providing, how does it know if the battery is still charging at 10
amps, or if the battery is full and there's a 10 amp load?

Not really true with anything but the most primative regulator like
you might see on an old outboard. Voltage is regulated somewhere
between 13.x and 14.x, not just reflecting what the alternator can do
against the load.
Rod is right, they look at current from the alternator

Every car I've seen, the the alternator, the battery
and the rest of the car are tied to one point

But there is normally more than the one wire
at the the positive terminal of the battery.

and there is no monitor for what current
is going to the battery vs to the car load.

Wrong when there is normally more than the one
wire at the the positive terminal of the battery.

And Rod is talking computers,

Because thats what his car has.

so how did cars work prior to the 80s?

The regulator uses the voltage it sees which varys
with the load and the charge of the battery.

That was my original question - on an old car,

Yours isnt that old.

there is no way for the regulator to tell the difference between the
battery still charging at 10 amps and the headlamps being switched on.

And thats one reason why old cars only used at night
could end up with not charging the battery enough.

They didn't have a computer didn't monitor anything
other than the voltage regulator maintained a constant
voltage of ~14v while the car was running.

Its more complicated than that with the voltage.

It was that way from the early days and auto batteries charged fine.

Generators do it differently to alternators and we arent discussing
whether they charged fine or not, we are discussing what the
regulator does when the battery is fully charged so that it doesnt
boil off the water in the battery. Thats particularly important
now that most car batterys arent refillable with water anymore.

Modern batteries are more resilient actually.

Thats only partly true. It is more accurate to say that they
dont boil off the water as much when overcharged because
of the different metal additions to the lead used in the plates.

There may be some modern cars where they do monitor the current going
to the battery, maybe to save energy and increase fuel consumption,

It actually to avoid ****ing the battery by delivering
the same current to the battery when its fully charged.

Wouldn't have to if they just charged at 13.8V, but I assume they're
trying to do a fast charge first.

Not only try but clearly do that for that reason and
you have in fact observed that yours does that.

but it's not necessary to keeping the battery charged.

That isnt what is being discussed either.

There is nothing they can do about the load so they don't
give a **** about the lights. The regulator just watches
alternator current and cranks up the voltage to keep it up.

That's rather bizarre. The alternator monitors current? So, what's
the correct current that it's targeting? 2 amps, 20 amps? 70 amps?
The current depends on what loads are on and the alternator doesn't
know that. Seems to me it keeps the system VOLTAGE at ~14V

No it doesnt. Doing that would overcharge a fully charged battery.

and that has worked for 100 years.

Wrong again, generators do it differently to alternators.

"Commander Kinsey" wrote in message
news
On Sat, 22 Jun 2019 01:17:29 +0100, wrote:

On Fri, 21 Jun 2019 23:55:31 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 23:48:01 +0100, wrote:

On Fri, 21 Jun 2019 23:15:21 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian
wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know when
to
switch to trickle charge? I can understand it noticing a drop in
charging current if the battery is on its own, but what if a random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change? That's determined by the alternator or
charger. Let's say the charger/alternator gives out 14.4V initially,
to charge the battery quickly. It'll just sit at 14.4V forever,
providing the charger can give out enough current to charge the
slightly flat battery and power any connected loads. If the battery
had no loads connected, it would take a lot less current when it
became full, but the voltage would stay the same. If the charger
monitored the current it was providing, how does it know if the
battery is still charging at 10 amps, or if the battery is full and
there's a 10 amp load?

Not really true with anything but the most primative regulator like
you might see on an old outboard. Voltage is regulated somewhere
between 13.x and 14.x, not just reflecting what the alternator can do
against the load.
Rod is right, they look at current from the alternator There is
nothing they can do about the load so they don't give a **** about the
lights. The regulator just watches alternator current and cranks up
the voltage to keep it up. When current drops off it is either because
there is less load or because the battery is taking less of a charge.
That is when the voltage ramps down.
If current gets really low, like the battery is charged and there is
not much load they hit the bottom of the range ... essentially a
trickle charger that is also running the radio and heater fan.

Take this situation: You start your car with the battery 3/4s full.
The alternator provides a high voltage and charges it quickly. It's
dark and cold, you have demisters, lights, etc on. How does the
alternator know when the battery is full? As current will continue to
be taken from it to power all those loads.

As for a smart charger, usually the voltage is all they need to know.
When the voltage drop across the battery starts to rise. it indicates
the battery is charging and at a certain point they either turn off or
turn to trickle.
Different batteries have different "fully charged" voltage levels so
they usually have a switch for different types . (deep cycle, AGM etc)

I guess charging a car battery with a charger plugged into the house
won't work if you have a load in the car like lights (or in my case a
faulty alarm). The charger will think the battery is still drawing a
fair current and isn't full, when in fact it's the load eating it up.

Plug in chargers are voltage regulated so that load would pull the
voltage down and the charger would try to bring it up. Once the
battery was charged the charger would either see a higher voltage and
ramp down or it would stay there at. what it could drive.

No, if you charge a battery with no load, the charger will sit at 14.4V
(provided it can give enough current to do that) until the battery drew
little current, then it would back off to 13.8V.

But with a load, the charger thinks the battery is still charging, when in
fact it's the load taking that current. So it will stay at 14.4V forever
and **** the battery.

That is
probably a good reason to turn all that crap off when you are charging
a battery off line

I don't have anything deliberately loading it.

and you might want to take the negative lead to the
car loose if you have too much residual load.

Too much hassle. Anyway if I was going to do that, which I used to, I
wouldn't even need a charger as the battery would never go flat.

Maybe you could figure
out what was killing the battery in the first place then.

I know it's the alarm,

No you don't.

as it still does it with every damn fuse pulled out.

Could still be a partial short in the wiring or with a
steaming turd with wheels frog car, something else
that isnt fused. It unlikely that the alarm isnt fused
because a fault in the alarm could set fire to the car.

The alarm is hidden away and difficult
to disconnect, to stop thieves doing so.

You previously proclaimed that all alarms should be permanently disabled.

"Commander Kinsey" wrote in message
news
On Sat, 22 Jun 2019 18:02:30 +0100, Rod Speed
wrote:



"trader_4" wrote in message
...
On Saturday, June 22, 2019 at 11:45:19 AM UTC-4, Rod Speed wrote:
"trader_4" wrote in message
...
On Friday, June 21, 2019 at 6:48:31 PM UTC-4, wrote:
On Fri, 21 Jun 2019 23:15:21 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian

wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know
when
to
switch to trickle charge? I can understand it noticing a drop
in
charging current if the battery is on its own, but what if a
random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change? That's determined by the alternator
or
charger. Let's say the charger/alternator gives out 14.4V
initially,
to
charge the battery quickly. It'll just sit at 14.4V forever,
providing
the charger can give out enough current to charge the slightly flat
battery and power any connected loads. If the battery had no loads
connected, it would take a lot less current when it became full,
but
the
voltage would stay the same. If the charger monitored the current
it
was providing, how does it know if the battery is still charging at
10
amps, or if the battery is full and there's a 10 amp load?

Not really true with anything but the most primative regulator like
you might see on an old outboard. Voltage is regulated somewhere
between 13.x and 14.x, not just reflecting what the alternator can
do
against the load.
Rod is right, they look at current from the alternator

Every car I've seen, the the alternator, the battery
and the rest of the car are tied to one point

But there is normally more than the one wire
at the the positive terminal of the battery.

Not on any car I've owned or worked on. And more to the point, it's
obviously not needed because cars have worked with the same lead-acid
batteries

They arent the same lead acid batterys, most of the current
ones cant be topped up with extra water when needed.

and alternators with basic voltage regulators for most of the last
century.

We havent used alternators for most of the last century.

and there is no monitor for what current
is going to the battery vs to the car load.

Wrong when there is normally more than the one
wire at the the positive terminal of the battery.

Even if there is an additional wire, explain to us how you
monitor the current in the charging cable with that wire.

With more than one wire, you can see
what the load from the lights etc is.

And you dont even have to do it that way
with modern computer controlled lights now.

I doubt it knows about everything, like how much power you're using from
the cigarette lighter socket etc.

Doesnt need to with that once because
it doesnt last long enough to matter.

Easier to just measure the total load in one go, than trying to add up
precise currents it thinks the wipers might be using etc.

Doesnt need to know that.

And Rod is talking computers,

Because thats what his car has.

But the essence of his question is how cars switch to
trickle charge and AFAIK, the answer is they don't.

The current to the battery does in fact drop
dramatically once the battery is fully charged.

The chemistry of the battery sees to that itself, but it's better for the
battery to lower the voltage from 14.4 to 13.8 when it's full.

The battery cant do that.

It's not as easy as a lithium cell where you just give it 4.2V.

Proper lithium cell chargers dont do that.

On 23/6/19 1:30 am, Rod Speed wrote:


"Xeno" wrote in message
...
On 22/6/19 7:58 pm, Rod Speed wrote:


"Xeno" wrote in message
...
On 22/6/19 9:57 am, Rod Speed wrote:


"Commander Kinsey" wrote in message
news On Fri, 21 Jun 2019 23:57:52 +0100, Rod Speed
wrote:



"Commander Kinsey" wrote in message
news On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian

wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know
when to
switch to trickle charge?* I can understand it noticing a drop in
charging current if the battery is on its own, but what if a
random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change?

That's the way batterys work, the battery voltage does change as its
charged.

That's determined by the alternator or charger.

Nope.

Yip.

Nope.

I can put any voltage I like across a battery's terminals.

Nope.

The battery then chooses how much current is drawn.

And that current changes depending on the how charged the battery is.

Let's say the charger/alternator gives out 14.4V initially, to
charge the
battery quickly.* It'll just sit at 14.4V forever, providing the
charger
can give out enough current to charge the slightly flat battery
and power
any connected loads.

Its more complicated than that with the current going to the
battery and the
battery is charged.

If the battery had no loads connected, it would take a lot less
current
when it became full, but the voltage would stay the same.

No it doesn't even with a very crude battery charger.

For example, I'm currently keeping my car's battery topped up with
a bench supply overnight.* It's set to 13.8V, with a current
limiter only to prevent overloading the supply.

It actually specify the current being supplied.

The voltage stays at 13.8V all the time, sometimes 100mA is drawn,
sometimes up to 4A.* The only way I or the supply can tell the
battery is full, is by the current dropping to 100mA.* But it's
actually always full, as when 4A is drawn, that's going to a load.

What load ?* There no load with a battery being charged with a
bench supply.

Correction

Nope.

the *battery* is the *load*.

Not when the battery is fully charged and is being charged
with a bench supply that is delivering 4A to the battery.

Take the case of an alternator charging a battery at ~4 amps.

That isnt what was being discussed there. What was being discussed
there was charging the battery out of the car with a bench supply.

The battery is the load and it also provides, as part of that
function, the* reference *voltage* that the alternator *must have* in
order to control* the output.

None of that is relevant to what was being discussed there,
charging the battery out of the car with a bench supply.

In the process of being charged it is using electric current. That
makes it the load.

See above.

What happens to the charger when you disconnect the power with the
battery connected?

With a BENCH SUPPLY, it continues to provide the
same voltage as it did with the battery connected.

It should, if designed correctly, shut down since it no longer sees a
load. Otherwise it may destroy itself.

That is just plain wrong with a BENCH SUPPLY.
None of those destroy themselves with no load.

Even when it is fully charged it will still take a trickle charge

4A isnt a trickle charge.

That depends entirely on the amp hour rating of the battery.

We're discussing a normal car battery in a steaming turd with
wheels frog car.

Also, my bench charger

We arent discussing a bench charger, we are discussing a bench SUPPLY.

will start off at 4 amps, its maximum capacity. As the battery becomes
charged, that current will drop down to *1 amp* and, from that point,
it will maintain a *trickle charge*.

So that is nothing like the situation being discussed
with a BENCH SUPPLY which is still delivering 4A to
a battery that has been removed from the car.

From Wikipedia;
*** For lead-acid batteries under no load float charging (such as
*** in SLI batteries), trickle charging happens naturally at the
*** end-of-charge, when the lead-acid battery internal resistance
*** to the charging current increases enough to reduce additional
*** charging current to a trickle, hence the name. In such cases,
*** the trickle charging equals the energy expended by the
*** lead-acid battery splitting the water in the electrolyte into
*** hydrogen and oxygen gases

Irrelevant to what is being discussed, 4A isnt a trickle charge.

The car alternator regulator is no different.

We arent discussing that there.

It sees the battery as a load, determines the voltage reference and
pumps up its output. When the regulator sees the battery voltage at
the peak setpoint, it too will drop the current to a trickle. If you
add a load, say by turning headlights on, that is in *parallel* to the
battery and it will drop the system voltage down a tad. The regulator
will see that and pump up the output current appropriately. The
current will apportion itself to the *two* loads as appropriate to
their individual internal resistances.

All irrelevant to charging a battery out of the car with a BENCH SUPPLY.

Here, educate yourself;
https://www.swtc.edu/ag_power/electr...l_circuits.htm

I knew all that before you were even born, thanks.

so it is still a load even when fully charged.

Not when its still taking 4A,

If the battery is *taking* 4 amps, then it *is definitely the load*.

But it wont be taking 4A WHEN THE BATTERY IS OUT OF THE
CAR WITH A BENCH SUPPLY. Because the battery voltage will
have risen once it has been charged so the original 4A will
have dropped significantly WITH A BENCH SUPPLY.

If you have a battery connected to a bench supply, it is still the load
because it will always be taking *some* current. If it is taking 4 amps
it is definitely loading the BENCH SUPPLY.

If the charger monitored the current it was providing, how does
it know if the battery is still charging at 10 amps, or if the
battery is full and there's a 10 amp load?

By checking the current actually being delivered to the battery.

I guess that may be true, if the car's computer has two ammeters

It has more than one wire to the positive terminal of the battery.
So it can see what current is going to the rest of the car.

and subtracts one from the other.** But AFAIK, the alternator
regulator only works by it's own current sensor.* And that current
could be going into the battery, or past it to the loads.

Not when there is more than one wire going to the
positive terminal of the battery, and there always is.




--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)

On 23/6/19 1:45 am, Rod Speed wrote:


"trader_4" wrote in message
...
On Friday, June 21, 2019 at 6:48:31 PM UTC-4, wrote:
On Fri, 21 Jun 2019 23:15:21 +0100, "Commander Kinsey"
wrote:

On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian
wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know
when to
switch to trickle charge?Â* I can understand it noticing a drop in
charging current if the battery is on its own, but what if a random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change?Â* That's determined by the alternator
or charger.Â* Let's say the charger/alternator gives out 14.4V
initially, to charge the battery quickly.Â* It'll just sit at 14.4V
forever, providing the charger can give out enough current to charge
the slightly flat battery and power any connected loads.Â* If the
battery had no loads connected, it would take a lot less current
when it became full, but the voltage would stay the same.Â* If the
charger monitored the current it was providing, how does it know if
the battery is still charging at 10 amps, or if the battery is full
and there's a 10 amp load?

Not really true with anything but the most primative regulator like
you might see on an old outboard. Voltage is regulated somewhere
between 13.x and 14.x, not just reflecting what the alternator can do
against the load.
Rod is right, they look at current from the alternator

Every car I've seen, the the alternator, the battery
and the rest of the car are tied to one point

But there is normally more than the one wire
at the the positive terminal of the battery.

Parallel circuits, so what?

and there is no monitor for what current
is going to the battery vs to the car load.

Wrong when there is normally more than the one
wire at the the positive terminal of the battery.

And Rod is talking computers,

Because thats what his car has.

so how did cars work prior to the 80s?

The regulator uses the voltage it sees which varys
with the load and the charge of the battery.

They didn't have a computer didn't monitor anything
other than the voltage regulator maintained a constant
voltage of ~14v while the car was running.

Its more complicated than that with the voltage.

No it isn't.

It was that way from the early days and auto batteries charged fine.

Generators do it differently to alternators and we arent discussing
whether they charged fine or not, we are discussing what the
regulator does when the battery is fully charged so that it doesnt
boil off the water in the battery. Thats particularly important
now that most car batterys arent refillable with water anymore.

There may be some modern cars where they do monitor the current going
to the battery, maybe to save energy and increase fuel consumption,

It actually to avoid ****ing the battery by delivering
the same current to the battery when its fully charged.

but it's not necessary to keeping the battery charged.

That isnt what is being discussed either.

There is nothing they can do about the load so they don't
give a **** about the lights.Â* The regulator just watches
alternator current and cranks up the voltage to keep it up.

That's rather bizarre.Â* The alternator monitors current?Â* So, what's
the correct current that it's targeting?Â* 2 amps, 20 amps?Â* 70 amps?
The current depends on what loads are on and the alternator doesn't
know that.Â* Seems to me it keeps the system VOLTAGE at ~14V

No it doesnt. Doing that would overcharge a fully charged battery.

and that has worked for 100 years.

Wrong again, generators do it differently to alternators.

Yes, no argument there. You mean like this;
http://mgaguru.com/mgtech/books/pdf/..._Box_Tests.pdf

Voltage and current control. They were pretty much on the way out by the
time I finished my apprenticeship.

With alternators, voltage is key.

You need to get with the times. Generators went out with button up boots.


--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)

On 23/6/19 1:57 am, Rod Speed wrote:


"trader_4" wrote in message
...
On Saturday, June 22, 2019 at 6:00:41 AM UTC-4, Brian Gaff wrote:
Yes indeed, the nominal output of an alternator can be as high as 15
volts,
but even a fully charged car battery is only 13.8v as far as I know and
these days, I'm sure the direction of current flow and voltages are
monitored very well by the computers. In the old days it was a bit of a
black art just relying on the ability of the alternator or dynamo in
the old
bangers.

Nonsense.Â* Cars used voltage regulators for better part of a century and
they are simple electronics which is well understood.Â* And, AFAIK,
that is STILL how it's done, all the FUD here notwithstanding.Â* Some
cars may have something more elaborate, but it's obviously not required
to keep the battery correctly charged, which was the OPs question about
charging.

No it wasnt, he asked about changing to a trickle charge when the battery
is fully charged.

Battery chargers do it automatically - if they are decent.
Alternators too do it automatically.

--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)

On 23/6/19 2:03 am, TMS320 wrote:
On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know when to
switch to trickle charge?

It doesn't.

I can understand it noticing a drop in charging current if the battery
is on its own, but what if a random changing load is connected, as
there is in a running car?

Ohm's law.


That's a bit *deep* for some people to comprehend.

--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)

"Xeno" wrote in message
...
On 23/6/19 1:30 am, Rod Speed wrote:


"Xeno" wrote in message
...
On 22/6/19 7:58 pm, Rod Speed wrote:


"Xeno" wrote in message
...
On 22/6/19 9:57 am, Rod Speed wrote:


"Commander Kinsey" wrote in message
news On Fri, 21 Jun 2019 23:57:52 +0100, Rod Speed
wrote:



"Commander Kinsey" wrote in message
news On Fri, 21 Jun 2019 22:57:44 +0100, Max Demian

wrote:

On 21/06/2019 21:19, Commander Kinsey wrote:
How does a lead acid battery charger (or car alternator) know
when to
switch to trickle charge? I can understand it noticing a drop
in
charging current if the battery is on its own, but what if a
random
changing load is connected, as there is in a running car?

The voltage perhaps.

Why would the voltage change?

That's the way batterys work, the battery voltage does change as
its
charged.

That's determined by the alternator or charger.

Nope.

Yip.

Nope.

I can put any voltage I like across a battery's terminals.

Nope.

The battery then chooses how much current is drawn.

And that current changes depending on the how charged the battery is.

Let's say the charger/alternator gives out 14.4V initially, to
charge the
battery quickly. It'll just sit at 14.4V forever, providing the
charger
can give out enough current to charge the slightly flat battery
and power
any connected loads.

Its more complicated than that with the current going to the
battery and the
battery is charged.

If the battery had no loads connected, it would take a lot less
current
when it became full, but the voltage would stay the same.

No it doesn't even with a very crude battery charger.

For example, I'm currently keeping my car's battery topped up with a
bench supply overnight. It's set to 13.8V, with a current limiter
only to prevent overloading the supply.

It actually specify the current being supplied.

The voltage stays at 13.8V all the time, sometimes 100mA is drawn,
sometimes up to 4A. The only way I or the supply can tell the
battery is full, is by the current dropping to 100mA. But it's
actually always full, as when 4A is drawn, that's going to a load.

What load ? There no load with a battery being charged with a bench
supply.

Correction

Nope.

the *battery* is the *load*.

Not when the battery is fully charged and is being charged
with a bench supply that is delivering 4A to the battery.

Take the case of an alternator charging a battery at ~4 amps.

That isnt what was being discussed there. What was being discussed
there was charging the battery out of the car with a bench supply.

The battery is the load and it also provides, as part of that function,
the reference *voltage* that the alternator *must have* in order to
control the output.

None of that is relevant to what was being discussed there,
charging the battery out of the car with a bench supply.

In the process of being charged it is using electric current. That
makes it the load.

See above.

What happens to the charger when you disconnect the power with the
battery connected?

With a BENCH SUPPLY, it continues to provide the
same voltage as it did with the battery connected.

It should, if designed correctly, shut down since it no longer sees a
load. Otherwise it may destroy itself.

That is just plain wrong with a BENCH SUPPLY.
None of those destroy themselves with no load.

Even when it is fully charged it will still take a trickle charge

4A isnt a trickle charge.

That depends entirely on the amp hour rating of the battery.

We're discussing a normal car battery in a steaming turd with
wheels frog car.

Also, my bench charger

We arent discussing a bench charger, we are discussing a bench SUPPLY.

will start off at 4 amps, its maximum capacity. As the battery becomes
charged, that current will drop down to *1 amp* and, from that point, it
will maintain a *trickle charge*.

So that is nothing like the situation being discussed
with a BENCH SUPPLY which is still delivering 4A to
a battery that has been removed from the car.

From Wikipedia;
For lead-acid batteries under no load float charging (such as
in SLI batteries), trickle charging happens naturally at the
end-of-charge, when the lead-acid battery internal resistance
to the charging current increases enough to reduce additional
charging current to a trickle, hence the name. In such cases,
the trickle charging equals the energy expended by the
lead-acid battery splitting the water in the electrolyte into
hydrogen and oxygen gases

Irrelevant to what is being discussed, 4A isnt a trickle charge.

The car alternator regulator is no different.

We arent discussing that there.

It sees the battery as a load, determines the voltage reference and
pumps up its output. When the regulator sees the battery voltage at the
peak setpoint, it too will drop the current to a trickle. If you add a
load, say by turning headlights on, that is in *parallel* to the battery
and it will drop the system voltage down a tad. The regulator will see
that and pump up the output current appropriately. The current will
apportion itself to the *two* loads as appropriate to their individual
internal resistances.

All irrelevant to charging a battery out of the car with a BENCH SUPPLY.

Here, educate yourself;
https://www.swtc.edu/ag_power/electr...l_circuits.htm

I knew all that before you were even born, thanks.

so it is still a load even when fully charged.

Not when its still taking 4A,

If the battery is *taking* 4 amps, then it *is definitely the load*.

But it wont be taking 4A WHEN THE BATTERY IS OUT OF THE
CAR WITH A BENCH SUPPLY. Because the battery voltage will
have risen once it has been charged so the original 4A will
have dropped significantly WITH A BENCH SUPPLY.

If you have a battery connected to a bench supply, it is still the load
because it will always be taking *some* current. If it is taking 4 amps it
is definitely loading the BENCH SUPPLY.

It wont be taking 4A when charged unless
you have completely ****ed up the voltage.

If the charger monitored the current it was providing, how does it
know if the battery is still charging at 10 amps, or if the
battery is full and there's a 10 amp load?

By checking the current actually being delivered to the battery.

I guess that may be true, if the car's computer has two ammeters

It has more than one wire to the positive terminal of the battery.
So it can see what current is going to the rest of the car.

and subtracts one from the other. But AFAIK, the alternator
regulator only works by it's own current sensor. And that current
could be going into the battery, or past it to the loads.

Not when there is more than one wire going to the
positive terminal of the battery, and there always is.