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Old July 11th 19, 03:01 PM posted to alt.electronics,uk.rec.driving,alt.home.repair,uk.d-i-y
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Default Lead acid battery charger (or alternator) switching to tricklewith load present?

On 11/7/19 7:09 pm, Daniel60 wrote:
Xeno wrote on 22/06/2019 9:03 PM:
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


Do Electric Cars have a 'standard' operating voltage?? Or does it vary
from one manufacturer to another??


It varies. Anything up to 600 volts DC seems to be the norm at present.
BEVs have a regulator to drop those very high voltages down to whatever
voltage the ancillaries require - between 12V and 48V typically.

--

Xeno


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

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Old July 11th 19, 03:25 PM posted to alt.electronics,uk.rec.driving,alt.home.repair,uk.d-i-y
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Default Lead acid battery charger (or alternator) switching to tricklewith load present?

On Thu, 11 Jul 2019 14:47:33 +0100, Xeno wrote:

On 11/7/19 5:11 am, Commander Kinsey wrote:
Well I see the full voltage charging a flat battery at idle. Obviously
they could be designed to be capable of this and it would be very useful
to charge the battery quickly when doing stop start town driving, or
driving at minimum revs in top gear in a town.

You may see a high voltage but you will not see a high current at idle.
The alternator is not *capable* of high current at idle.


A flat battery at a high voltage means there's a high current.

And will you please stop mixing up top and bottom posting. I top posted because I was replying to a blind user who had done the same.


On Sun, 23 Jun 2019 07:07:14 +0100, Xeno wrote:

On 23/6/19 5:47 am, Commander Kinsey wrote:
Modern car alternators seem to be able to give out a huge amount of
current at engine idle speed. I'm sure my friend got his to give out
pretty much the full 80 amps without revving the engine. He was
powering a small disco on a campsite :-)

No way to get a full 80 amps out of an alternator *at idle*.

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

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

Brian


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Old July 11th 19, 03:47 PM posted to alt.electronics,uk.rec.driving,alt.home.repair,uk.d-i-y
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Default Troll-feeding Senile Australian ASSHOLE Alert

On Thu, 11 Jul 2019 23:47:33 +1000, Xeno, another brainless, troll-feeding,
senile Australian idiot, blathered:



You may see a high voltage but you will not see a high current at idle.
The alternator is not *capable* of high current at idle.


What we see is you AUSTRALIAN senile ASSHOLE taking every single bait the
Scottish ****** sets out for you! Just HOW senile are you, idiot?
  #84   Report Post  
Old July 11th 19, 04:35 PM posted to alt.electronics,uk.rec.driving,alt.home.repair,uk.d-i-y
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Default Lead acid battery charger (or alternator) switching to trickle with load present?



"Daniel60" wrote in message
...
Xeno wrote on 22/06/2019 9:03 PM:
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


Do Electric Cars have a 'standard' operating voltage??


Nope.

Or does it vary from one manufacturer to another??


And from one model to another too.

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Old July 11th 19, 10:02 PM posted to alt.electronics,uk.rec.driving,alt.home.repair,uk.d-i-y
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Default Lead acid battery charger (or alternator) switching to tricklewith load present?

On 11/07/2019 14:47, Xeno wrote:
On 11/7/19 5:11 am, Commander Kinsey wrote:
Well I see the full voltage charging a flat battery at idle.
Obviously they could be designed to be capable of this and it would be
very useful to charge the battery quickly when doing stop start town
driving, or driving at minimum revs in top gear in a town.

You may see a high voltage but you will not see a high current at idle.
The alternator is not *capable* of high current at idle.



You would be surprised.

Howver 80A at 12v is only a brake horsepower and a bit..





On Sun, 23 Jun 2019 07:07:14 +0100, Xeno
wrote:

On 23/6/19 5:47 am, Commander Kinsey wrote:
Modern car alternators seem to be able to give out a huge amount of
current at engine idle speed.* I'm sure my friend got his to give out
pretty much the full 80 amps without revving the engine.* He was
powering a small disco on a campsite :-)

No way to get a full 80 amps out of an alternator *at idle*.


That however is probably true for most car alternators




--
Labour - a bunch of rich people convincing poor people to vote for rich
people
by telling poor people that "other" rich people are the reason they are
poor.

Peter Thompson


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Old July 12th 19, 07:56 AM posted to alt.electronics,uk.rec.driving,alt.home.repair,uk.d-i-y
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Default Lead acid battery charger (or alternator) switching to tricklewith load present?

Daniel60 wrote on 11/07/2019 7:09 PM:
Xeno wrote on 22/06/2019 9:03 PM:
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


Do Electric Cars have a 'standard' operating voltage?? Or does it vary
from one manufacturer to another??

Ah!! Good to read there is consistency ...... *NOT* !! ;-P

--
Daniel
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Old July 12th 19, 02:37 PM posted to alt.electronics,uk.rec.driving,alt.home.repair,uk.d-i-y
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Default Lead acid battery charger (or alternator) switching to tricklewith load present?

On 12/07/2019 07:56, Daniel60 wrote:
Daniel60 wrote on 11/07/2019 7:09 PM:


Do Electric Cars have a 'standard' operating voltage?? Or does it vary
from one manufacturer to another??

Ah!! Good to read there is consistency ...... *NOT* !! ;-P

More volts requires more cells. Better to standardise on the size of a
cell, set a maximum operating current and alter the number of cells
according to cost/power requirements.
  #88   Report Post  
Old July 12th 19, 06:23 PM posted to alt.electronics,uk.rec.driving,alt.home.repair,uk.d-i-y
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Default Lead acid battery charger (or alternator) switching to tricklewith load present?

On Sun, 23 Jun 2019 03:59:55 +0100, Rod Speed wrote:



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


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


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


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



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

wrote:

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

The voltage perhaps.

Why would the voltage change?

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

That's determined by the alternator or charger.

Nope.

Yip.

Nope.

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

Nope.

The battery then chooses how much current is drawn.

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

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

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

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

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

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

It actually specify the current being supplied.

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

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

Correction

Nope.

the *battery* is the *load*.

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

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

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

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

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

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

See above.

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

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

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

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

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

4A isnt a trickle charge.

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

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

Also, my bench charger

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

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

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

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

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

The car alternator regulator is no different.

We arent discussing that there.

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

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

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

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

so it is still a load even when fully charged.

Not when its still taking 4A,

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

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


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


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


Or a cell has died, in which case you have a 10V battery. I've done that and caused an explosion.
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Old July 12th 19, 08:10 PM posted to alt.electronics,uk.rec.driving,alt.home.repair,uk.d-i-y
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Default Lead acid battery charger (or alternator) switching to tricklewith load present?

On 12/07/2019 14:37, TMS320 wrote:
On 12/07/2019 07:56, Daniel60 wrote:
Daniel60 wrote on 11/07/2019 7:09 PM:


Do Electric Cars have a 'standard' operating voltage?? Or does it
vary from one manufacturer to another??

Ah!! Good to read there is consistency ...... *NOT* !! ;-P

*More volts requires more cells. Better to standardise on the size of a
cell, set a maximum operating current and alter the number of cells
according to cost/power requirements.


Better still, standardised voltage and standardised packs where a small
town car may use one, while a larger, longer range car may use two or
three. Make the packs so they can be slid in or out - it doesn't matter
if each car puts them in at different locations, in different directions
or around different obstructions - and "battery stations" could use
robot arms, pre-programmed for all different models, to swap out
discharged batteries for fully charged ones. The service paid for at a
fixed sum, plus a rate for the increase in charge level.

That makes recharging an electric vehicle as fast as a petrol or diesel
one from the driver's point of view and ensures that failing batteries
are removed from circulation, with the cost spread amongst all drivers
rather than an individual being hit by a high fee.

It would also mean that as battery technology improved, all cars would
benefit, not just the latest model.

SteveW
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Old July 13th 19, 11:15 AM posted to alt.electronics,uk.rec.driving,alt.home.repair,uk.d-i-y
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Default Lead acid battery charger (or alternator) switching to trickle with load present?

In article ,
Steve Walker wrote:
Better still, standardised voltage and standardised packs where a small
town car may use one, while a larger, longer range car may use two or
three. Make the packs so they can be slid in or out - it doesn't matter
if each car puts them in at different locations, in different directions
or around different obstructions - and "battery stations" could use
robot arms, pre-programmed for all different models, to swap out
discharged batteries for fully charged ones. The service paid for at a
fixed sum, plus a rate for the increase in charge level.


That makes recharging an electric vehicle as fast as a petrol or diesel
one from the driver's point of view and ensures that failing batteries
are removed from circulation, with the cost spread amongst all drivers
rather than an individual being hit by a high fee.


It would also mean that as battery technology improved, all cars would
benefit, not just the latest model.


Which would require cooperation between every maker in every country.
Just the thing all the Farages and Trumps of this world are dead against.
How dare anyone tell us how we should do things. And so on.

--
*If you tell the truth, you don't have to remember anything.*

Dave Plowman London SW
To e-mail, change noise into sound.


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