On 03/05/2020 09:22, The Natural Philosopher wrote:
On 03/05/2020 08:52, Harry Bloomfield wrote:
williamwright was thinking very hard :
You are forgetting the internal resistance of the battery. The fact
is that the most charge a car will give a flat battery is around 30A,
it it drops off very rapidly. The high alternator output is to
support accessories.

Correct! I have taken the trouble to actually measure it and have seen
20 to maybe 30amps delivered by a 130amp alternator, into a near flat
battery. That level of charge current rapidly declines as the flat
battery gains in voltage.

I have battery chargers that will dump full permitted current into a
battery until it is =99% full.


Yes, intelligent chargers with a temperature sensor strapped to the side
of the battery.

Bill