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