On Fri, 21 Jun 2019 20:17:29 -0400, , another mentally
challenged, troll-feeding, senile Yankietard, blathered again:

That is
probably a good reason to turn all that crap off

If one could only all the crap off that this sociopathic troll and all you
troll-feeding senile idiots keep producing together with him! tsk

On 22/6/19 7:18 am, trader_4 wrote:
On Friday, June 21, 2019 at 4:54:51 PM UTC-4, Rod Speed wrote:
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.

Except that the alternator doesn't know how much current is going
into the battery and how much is being used to power the car.
At least not in any car I've had. The alternator is tied directly
to the battery and that common point supplies the car. The alternator
can't switch to trickle charge either. EVery one I've seen, with
the car running normally, the voltage at the alternator/battery is
about 13.5 - 14V

The alternator knows jack **** about either the current or the voltage.
Assuming a constant excitation current at the alternator field coils,
the alternator voltage is determined by the *speed* the alternator runs
at and the *load* that is applied to it.

What does control the alternator is the *voltage regulator*. This
regulator can be external or, most often these days, built into the
alternator's rear housing. The regulator has the job of maintaining the
alternator voltage and, therefore, the vehicle system voltage. The
regulator controls the level of the field excitation current in the
rotor. By doing this it controls the intensity of the magnetic field in
the rotor as a function of the voltage generated in the alternator. In
this way the regulator keeps the system voltage constant at around 14V.
To do this the regulator switches the rotor field current off and on
very rapidly to average it out so that alternator generated voltage
doesn't exceed set limits. A Zener diode is used as the alternators
set-point generator. A second diode, with a negative temperature
coefficient, is used for temperature compensation. In low temperatures
the 2nd diode keeps the alternator output a little higher and at high
temperatures reduces it slightly to prevent battery gassing.

When a load is added to the circuit, it causes the voltage to drop and
this will increase the alternator output current. Same with the battery,
as the state of charge increases, the voltage will rise and the
regulator will begin reducing the alternator output commensurately. When
the battery is fully charged its voltage will be high so alternator
charge output will be reduced to a *trickle*, enough to keep a little
current flowing through the battery and supply any other power needs of
the system. In the old days of coil ignition, a vehicle's alternator
output could be as little as 5 amps - 4 amps for the ignition coil and 1
amp to keep the battery happy after it's fully charged and all that was
needed was a 40 amp unit. Not so these days where an alternator could be
supplying 25 amps and more to all the electrical circuits that are
required. 60 and 80 amp alternators are now common on cars to cope with
this *extra loading*.

In summary, the *regulator* is sensing *voltage* and will run up the
alternator current output to whatever maximum limit it has in order to
reach that voltage target of 14.2-14.4 volts. That could be 40-80 amps.
This is the reason why, when you fully flatten a battery, it is best to
remove it and slow charge it using 10% of the rated capacity. ie. for a
40 AH battery, you charge it at 4 amps. You can charge it a little
faster than that, say 8-10 amps, if you're in a rush but putting a fast
charger on it, which is what the car's alternator effectively is, will
create a lot of heat in the battery and can damage or buckle plates.
Certainly fast charging will abbreviate the battery's life.


--

Xeno


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

On 22/6/19 9:33 am, 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.

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.

Nope, the alternator regulator is sensing only *voltage*.

--

Xeno


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

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 - the *battery* is the *load*. In the process of being
charged it is using electric current. That makes it the load. Even when
it is fully charged it will still take a trickle charge so it is still a
load even when fully charged.

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)

"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.

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

See above.

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

4A isnt a trickle charge.

so it is still a load even when fully charged.

Not when its still taking 4A,

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.

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

--
----- --
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 19:58:32 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:


Correction

Nope.

LOL Clinically insane 85-year-old senile pest!

--
Kerr-Mudd,John addressing senile Rot:
"Auto-contradictor Rod is back! (in the KF)"
MID:

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.

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 19:15:56 +1000, Xeno, another brain damaged,
troll-feeding, senile Australian idiot, blathered:


Nope, the alternator regulator is sensing only *voltage*.

Nope, it's the Scottish ****** sensing that he can have all you senile
troll-feeding idiots on, time and again! BG

On Sat, 22 Jun 2019 20:11:33 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

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


You ALWAYS have to go one better, eh, you abnormal senile asshole? Can't you
see that that's the very reason why you got NO ONE in real life to talk to?
BG

--
Richard addressing Rot Speed:
"**** you're thick/pathetic excuse for a troll."
MID:

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.

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.

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*.
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

The car alternator regulator is no different. 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.

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

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*.

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)

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.

On 22/6/19 8:00 pm, 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

A 12 Volt lead acid battery will show 13.2 volts straight off the
charger, about 2.2 volts per cell. That will drop to about 12.7 volts
after a day or so, a tad over 2.1 volts per cell.

On the other hand, a vehicle's nominal *system voltage* is 14 Volts.
That's because the *alternator typically operates in the 13.8-14.2 range.

Due to increasing loads on vehicle electrical equipment, manufacturers
were pushing to a nominal 42 Volt electrical system on cars. They were
to be equipped with a 36 Volt battery. It may not happen now.
https://en.wikipedia.org/wiki/42-volt_electrical_system


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

Most batteries fail gracefully as they progressively lose *capacity*.
The first sign of impending doom is a lack of gusto on the first turn of
the engine on the first cold start of the day. Batteries don't like cold
weather, their chemistry just isn't happy. The rest of the day they will
start pretty much as normal. Most people however aren't as attuned to
this so fail to observe that subtle change. It won't get better however
and it will eventually be noticeable by all and sundry as it will, one
slightly colder morning, fail to start the car at all.

--

Xeno


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

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.



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.

On Friday, June 21, 2019 at 6:44:36 PM UTC-4, Rod Speed wrote:
"trader_4" wrote in message
...
On Friday, June 21, 2019 at 4:54:51 PM UTC-4, Rod Speed wrote:
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.

Except that the alternator doesn't know how much current
is going into the battery and how much is being used to
power the car.At least not in any car I've had.

Have fun explaining how you can have an ammeter
which shows the current that is going to the battery.


Because then there is an ammeter, dummy. I have yet to see a car
that has a sensor in the cable path to the battery. And obviously
it's not needed because lead acid car batteries worked for most of
a century BEFORE there was any computer to monitor or control anything
and the batteries worked fine, lasted just as long.



Ditto with an OBD2 dongle.

That is just a connection to the computer dummy and cars had batteries
for most of a century BEFORE OBD2.




The alternator is tied directly to the battery

Yes.

and that common point supplies the car.

Nope. And there isnt normally just the
one wire at the positive battery terminal.

BS as proven by all the cars I've worked on over the years. Battery,
alternator, car loads all tied to one common point. And the VOLTAGE
regulator simply monitors that common point for VOLTAGE.

On Saturday, June 22, 2019 at 5:12:48 AM UTC-4, Xeno wrote:
On 22/6/19 7:18 am, trader_4 wrote:
On Friday, June 21, 2019 at 4:54:51 PM UTC-4, Rod Speed wrote:
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.

Except that the alternator doesn't know how much current is going
into the battery and how much is being used to power the car.
At least not in any car I've had. The alternator is tied directly
to the battery and that common point supplies the car. The alternator
can't switch to trickle charge either. EVery one I've seen, with
the car running normally, the voltage at the alternator/battery is
about 13.5 - 14V

The alternator knows jack **** about either the current or the voltage.

That depends on how you define alternator. On many cars today, the voltage
regulator is part of the alternator, when you buy a replacement it comes
with it.




Assuming a constant excitation current at the alternator field coils,
the alternator voltage is determined by the *speed* the alternator runs
at and the *load* that is applied to it.

What does control the alternator is the *voltage regulator*. This
regulator can be external or, most often these days, built into the
alternator's rear housing. The regulator has the job of maintaining the
alternator voltage and, therefore, the vehicle system voltage.

+1

Exactly what I've said too.

The
regulator controls the level of the field excitation current in the
rotor. By doing this it controls the intensity of the magnetic field in
the rotor as a function of the voltage generated in the alternator. In
this way the regulator keeps the system voltage constant at around 14V.
To do this the regulator switches the rotor field current off and on
very rapidly to average it out so that alternator generated voltage
doesn't exceed set limits. A Zener diode is used as the alternators
set-point generator. A second diode, with a negative temperature
coefficient, is used for temperature compensation. In low temperatures
the 2nd diode keeps the alternator output a little higher and at high
temperatures reduces it slightly to prevent battery gassing.

When a load is added to the circuit, it causes the voltage to drop and
this will increase the alternator output current. Same with the battery,
as the state of charge increases, the voltage will rise and the
regulator will begin reducing the alternator output commensurately. When
the battery is fully charged its voltage will be high so alternator
charge output will be reduced to a *trickle*, enough to keep a little
current flowing through the battery and supply any other power needs of
the system.

Agree, except it;s obviously not a trickle. Todays cars have a lot of
loads in them to be powered, which is why they use 100 amp alternators.





In the old days of coil ignition, a vehicle's alternator
output could be as little as 5 amps - 4 amps for the ignition coil and 1
amp to keep the battery happy after it's fully charged and all that was
needed was a 40 amp unit. Not so these days where an alternator could be
supplying 25 amps and more to all the electrical circuits that are
required. 60 and 80 amp alternators are now common on cars to cope with
this *extra loading*.

In summary, the *regulator* is sensing *voltage* and will run up the
alternator current output to whatever maximum limit it has in order to
reach that voltage target of 14.2-14.4 volts. That could be 40-80 amps.
This is the reason why, when you fully flatten a battery, it is best to
remove it and slow charge it using 10% of the rated capacity. ie. for a
40 AH battery, you charge it at 4 amps. You can charge it a little
faster than that, say 8-10 amps, if you're in a rush but putting a fast
charger on it, which is what the car's alternator effectively is, will
create a lot of heat in the battery and can damage or buckle plates.
Certainly fast charging will abbreviate the battery's life.


--

Xeno


Agree with you.
Now maybe you can explain that to the folks that are talking about computers, OBD2, and the alternator monitoring current output.

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. Cars used voltage regulators for better part of a century and
they are simple electronics which is well understood. And, AFAIK,
that is STILL how it's done, all the FUD here notwithstanding. 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.

On Friday, June 21, 2019 at 6:15:26 PM UTC-4, 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?

In all the cars I'm familiar with and have worked on, the answer is it
doesn't know and doesn't care.

On 23/6/19 12:58 am, trader_4 wrote:
On Saturday, June 22, 2019 at 5:12:48 AM UTC-4, Xeno wrote:
On 22/6/19 7:18 am, trader_4 wrote:
On Friday, June 21, 2019 at 4:54:51 PM UTC-4, Rod Speed wrote:
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.

Except that the alternator doesn't know how much current is going
into the battery and how much is being used to power the car.
At least not in any car I've had. The alternator is tied directly
to the battery and that common point supplies the car. The alternator
can't switch to trickle charge either. EVery one I've seen, with
the car running normally, the voltage at the alternator/battery is
about 13.5 - 14V

The alternator knows jack **** about either the current or the voltage.

That depends on how you define alternator. On many cars today, the voltage
regulator is part of the alternator, when you buy a replacement it comes
with it.

I was considering the regulator to be a separate discrete device, even
where it is built into the back of the alternator. It can be removed as
a discrete entity



Assuming a constant excitation current at the alternator field coils,
the alternator voltage is determined by the *speed* the alternator runs
at and the *load* that is applied to it.

What does control the alternator is the *voltage regulator*. This
regulator can be external or, most often these days, built into the
alternator's rear housing. The regulator has the job of maintaining the
alternator voltage and, therefore, the vehicle system voltage.

+1

Exactly what I've said too.

The
regulator controls the level of the field excitation current in the
rotor. By doing this it controls the intensity of the magnetic field in
the rotor as a function of the voltage generated in the alternator. In
this way the regulator keeps the system voltage constant at around 14V.
To do this the regulator switches the rotor field current off and on
very rapidly to average it out so that alternator generated voltage
doesn't exceed set limits. A Zener diode is used as the alternators
set-point generator. A second diode, with a negative temperature
coefficient, is used for temperature compensation. In low temperatures
the 2nd diode keeps the alternator output a little higher and at high
temperatures reduces it slightly to prevent battery gassing.

When a load is added to the circuit, it causes the voltage to drop and
this will increase the alternator output current. Same with the battery,
as the state of charge increases, the voltage will rise and the
regulator will begin reducing the alternator output commensurately. When
the battery is fully charged its voltage will be high so alternator
charge output will be reduced to a *trickle*, enough to keep a little
current flowing through the battery and supply any other power needs of
the system.

Agree, except it;s obviously not a trickle. Todays cars have a lot of
loads in them to be powered, which is why they use 100 amp alternators.

Poorly worded. My bad. I meant/should have written the battery will only
be *taking* a trickle, only what it needs to maintain it's charge. The
rest of the circuit(s) will be taking whatever it needs. I made that
point in another post on the topic.




In the old days of coil ignition, a vehicle's alternator
output could be as little as 5 amps - 4 amps for the ignition coil and 1
amp to keep the battery happy after it's fully charged and all that was
needed was a 40 amp unit. Not so these days where an alternator could be
supplying 25 amps and more to all the electrical circuits that are
required. 60 and 80 amp alternators are now common on cars to cope with
this *extra loading*.

In summary, the *regulator* is sensing *voltage* and will run up the
alternator current output to whatever maximum limit it has in order to
reach that voltage target of 14.2-14.4 volts. That could be 40-80 amps.
This is the reason why, when you fully flatten a battery, it is best to
remove it and slow charge it using 10% of the rated capacity. ie. for a
40 AH battery, you charge it at 4 amps. You can charge it a little
faster than that, say 8-10 amps, if you're in a rush but putting a fast
charger on it, which is what the car's alternator effectively is, will
create a lot of heat in the battery and can damage or buckle plates.
Certainly fast charging will abbreviate the battery's life.


--

Xeno


Agree with you.
Now maybe you can explain that to the folks that are talking about computers, OBD2, and the alternator monitoring current output.


The only thing worth saying about that is that the voltage regulators on
some vehicles are computer controlled. Too recent for me to have much
experience with them since I retired 18 years ago.

--

Xeno


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

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. 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, 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.

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.




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" 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 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.

"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.

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.

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. 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.

"trader_4" wrote in message
...
On Friday, June 21, 2019 at 6:44:36 PM UTC-4, Rod Speed wrote:
"trader_4" wrote in message
...
On Friday, June 21, 2019 at 4:54:51 PM UTC-4, Rod Speed wrote:
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.

Except that the alternator doesn't know how much current
is going into the battery and how much is being used to
power the car.At least not in any car I've had.

Have fun explaining how you can have an ammeter
which shows the current that is going to the battery.

Because then there is an ammeter, dummy.

It isnt in series with just the battery, stupid.

I have yet to see a car that has a sensor in the cable path to the
battery.

Dont need one, you measure the voltage drop across
the cable. The resistance of that doesnt vary enough
to matter and so that tells you the current.

And obviously it's not needed because lead acid car batteries
worked for most of a century BEFORE there was any computer
to monitor or control anything

Generators do it differently to alternators and now you
cant add more water to the battery if it has boiled off
some of the water because its been charged at the
same current as it was charged at when flat.

and the batteries worked fine,

In fact they worked worse with generators
when you had used up most of the charge
when it wouldnt start when very cold.

lasted just as long.

Thats wrong too.

Ditto with an OBD2 dongle.

That is just a connection to the computer dummy and
cars had batteries for most of a century BEFORE OBD2.

Thats how you see the current going to the
battery when there isnt an ammeter, ****wit.

The alternator is tied directly to the battery

Yes.

and that common point supplies the car.

Nope. And there isnt normally just the
one wire at the positive battery terminal.

BS as proven by all the cars I've worked on over the years.
Battery, alternator, car loads all tied to one common point.

Normally the positive terminal of the battery.

And the VOLTAGE regulator simply monitors
that common point for VOLTAGE.

Wrong with computer controlled cars.

"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. Cars used voltage regulators for better part of a century and
they are simple electronics which is well understood. And, AFAIK,
that is STILL how it's done, all the FUD here notwithstanding. 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.

"trader_4" wrote in message
...
On Friday, June 21, 2019 at 6:15:26 PM UTC-4, 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?

In all the cars I'm familiar with and have worked on, the answer is it
doesn't know and doesn't care.

Thats bull****. No well designed car keeps charging the battery at the
same rate as it did just after it has been started when you have drained
\the battery well down when its hard to start in very cold weather.

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.

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 and alternators with basic voltage regulators 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.




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





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".





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? Alternators with voltage
regulators have been used with lead-acid batteries in cars for the
better part of the last century. And the principles with generators
are the same.





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. We can point you to many auto websites which will
explain it, how it simply uses an alternator and a simple voltage regulator..
So here's an idea. You provide us some references that show the
more elaborate method that you claim is actually what is used
today in all cars. And why it's needed when the other system works.
????????

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 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.

No they aren't, unless one has been added.


--
Bod

---
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On Sun, 23 Jun 2019 01:30:41 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

FLUSH another 209 !!! lines of senile bull**** unread again

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

On Sun, 23 Jun 2019 01:54:25 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

FLUSH more of the senile cretin's usual troll****

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

On Sun, 23 Jun 2019 01:57:14 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

FLUSH senile asshole's troll****

01:57 am in Australia, AGAIN? And you are out of bed and trolling, AGAIN?
Just what is wrong with you? Is it your senile hormones? Or the fact that
you have absolutely NOBODY to talk to in real life? VBG

--
"Anonymous" to trolling senile Rot Speed:
"You can **** off as you know less than pig **** you sad
little ignorant ****."
MID:

On Sun, 23 Jun 2019 01:45:08 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

FLUSH the sleepless senile asshole's latest stinking troll****

01:45 am in Australia, AGAIN? So when did you actually get out of bed and
start trolling? At about one o'clock, you subnormal idiot?

--
Richard addressing Rot Speed:
"**** you're thick/pathetic excuse for a troll."
MID:

On Sun, 23 Jun 2019 01:59:14 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

FLUSH senile asshole's troll****

01:59 am in Australia? So why can you NEVER sleep in, senile cretin? Is it
because of your senile hormones? Or because you can't wait until you got
someone to "talk to" on Usenet, you forsaken senile pest?

--
Bod addressing senile Rot:
"Rod, you have a sick twisted mind. I suggest you stop your mindless
and totally irresponsible talk. Your mouth could get you into a lot of
trouble."
Message-ID:

"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.

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?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.

Not on any car I've owned or worked on.Â* 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.Â* 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 (just to let you know).
Or do Aussies spell it that way?
--
Bod

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

"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.

Or do Aussies spell it that way?

Nope.

On Sat, 22 Jun 2019 18:24:38 +0100, Bod wrote:

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 (just to let you know).
Or do Aussies spell it that way?

He's stated before that he spells things the way he thinks they should be, as I do but worse. I write "pronounciation" for example, because it comes from the word "pronounce", not "pronunce".

And who knows if it's adaptor or adapter?

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.

On Sat, 22 Jun 2019 18:24:38 +0100, Bod wrote:


They arent the same lead acid batterys.

Rod, you keep spelling *batteries* incorrectly (just to let you know).
Or do Aussies spell it that way?

It's a sociopathic thing with him, just like with Hucker. He insists on his
right to wilfully write it that way, just like that other sociopathic
Scottish ****** insists on his right to spell words the way he wants to
write them. BG