jterp

Why does the battery read 14.4 volts? It's a regular 12V battery, right?

ZeusC6

All batterys measure over 12 volts when tested if its a good battery. I thought it was more like 13.4 than 14 but none the less, over 12vdc

Wcberry

If the engine is running when you measure it, it will be more than 12 volts, typically 13.8 volts. Takes more than 12 volts to charge a 12 volt battery.

parkland_c6

Alternators always run at 14.4 Volts in order to properly charge the battery and run accessories

jterp

Thanks!

c2c4c6

But why does the digital display run between 13.7 and 14.2 volts?

shopdog

A fully charged battery measures 12.5 volts. But just after full charge is reached, battery voltage will be 13.8 volts. This extra voltage is called "surface charge" and even a small discharge will cause the battery to drop back to 12.5 volts. But to charge the battery, it is necessary for the charging voltage to be higher than the surface charge voltage. Thus normal running voltage in the car will be in the range of 14.2 to 14.4 volts.

LS WON

VET4LES

speedz06

each cell is over 2 volts like 2.6 per cell (I think) times 6 is about 13.2v on a 12 volt Batt. Alternators can charge up to 14.7 as old school tech goes but some cars may be different today.Alts regulation doesnt always go up to 14.7 only as needed.Amp ratings depend on the alt options.There are a few different amp alternators available.

Curtis A. Franz

Actually led acid wet cells are 2.2 volts each. One can measure a "surface" charge on top of the expected voltage after turning off the engine. That surface charge disipates shortly. That is essentially what is said above.

Curtis A. Franz

Most GM alternators are 105 amps. Way back in the 50's when I was working on cars thay were 35-50 amps (as generators). I suspect that trucks and bigger SUV's are even higher amperage. Rear window defoggers suck up the amps.