Re: APC Smart-UPS float voltage experiment



Personally, I think the perfect float voltage is 27.27 volts. It should be high enough to stay out of the sulphation issue and gentle enough to make the batteries last a long time.

I have a SU300NET and added a potentiometer as a replacement to the R118 resistor so that I could adjust the voltage with a screwdriver. The original batteries were more then 2 litres low on electrolyte due to an improperly high float voltage (just short of 28 volts).

While you're in there be sure to check out R38...