"trader_4" wrote in message
...
On Monday, June 24, 2019 at 2:06:04 PM UTC-4, wrote:
Basically all cars before say 2010, the alternator VOLTAGE is regulated
to 13.4 to 14.5 volts and the battery draws as much current as it need
to, to charge.
When the battery is fully charged it draws only a small current. The
exact voltage the alternator is regulated to actually changes a little
with temperature, up a little in cold down in hot. That battery
university web site has a lot of good detail.

BUT,

I did hear that some newer cars have some weird mode where the computer
sets the alternator to a lower voltage as a fuel saving measure. That
may be what the poster was seeing.

What year was the car you saw this behavior?

m

I agree, both with how traditional VRs worked and that newer cars may
have something more advanced. What I disagree with is people making up
pure BS, speculation, and then asserting it as fact. That fool Kinsey
even dismisses the idea of supplying some cites or references. And also
it's
obviously not essential to do a new method, because the traditional dumb
VRs worked for more than a half century with the same lead acid batteries.

Different lead acid batterys in fact.

There is no need to back off to trickle charging, etc.

But if the system deliberately charges more aggressively initially
so that the battery is more fully charged with start stop driving,
particularly with engines that now are stopped automatically
when the car is stopped at the lights etc, it may well be very
desirable to back off that charging when the battery is charged.