Re: The Duchess Project: 1940 Super 8 Convertible Sedan

Posted by TxGoat On 2023/5/31 12:55:11

If your car has a 3 brush generator with voltage regulator, It may be able to develp an excessively high charge rate when batteries are low or all accessories are in use, or both. If so, it may damage the generator and perhaps battery(s) under some conditions. Setting the 3rd brush so as to limit generator output to about 75% of it's rating may help preserve the generator and battery(s).
As I (imperfectly) understand it, the early, 2-element voltage regulator units contained a cutout and a voltage regulating element.
They are somewhat application-specific, since diffgerent models and brands of cars have different generator capabilities. The older units were designed to operate with standard lead-acid batteries.

The later, 3-element regulators are able to regulate both voltage and current, and they do a better job of serving the battery's needs and protecting the generator, and might be expected to do a better job of dealing with modern Optima-type batteries.

It's also worth noting that automotive gnerators and alternators are NOT designed to charge stone dead or heavily-discharged batteries.

It's best to charge low or dead batteries with a charger that is designed for the type of battery you are using.

A heavily-discharged battery can draw a very heavy current, which can overwork a generator or alternator.

Batteries that are in poor condition may
cause issues with charging systems.
A battery with a broken cell connector may allow system voltage to go way too high, and caused a burned out generator and burned out lights. One with a shorted cell might draw too much charging current and cause the remaining active cells to overcharge and boil.