Originally Posted by moparx
as i understand, 13.8-14.2 is acceptable rate of charge for a 12v dc battery.
now with that said, would it be possible for the voltage gauge mounted inside the car, to pick up a 14.7v signal from the alternator, but if measured voltage at the battery, to be only 14.2 volts due to voltage drop throughout the system ?
also, how accurate are most aftermarket voltage gauges compared to a fluke meter, which many do not own ? [i own several, but i have never taken the time to compare readings against a parts store gauge]
beer


Well things get a little funny sometimes....a fully charged lead battery will measure 12.6 volts, but will never get there without 13.2 volt charge rate, or 14.25 dead cold. I have seen computer controlled regulators with battery temp sensors hit 14.7 at -10 temperature. Sometimes you readings are skewed even with a fluke meter, the reason is that as a battery charges it gases off and that gas inside becomes a sort of phantom cell, showing up as a little higher voltage. Load the battery a little to burst those bubbles to get a true reading with any battery. Headlights on and off works pretty good. I have an optima that sees 14.7 all the time cold and it is 5 years old, no issue, agm batterys seem to be fine with that high voltage also.