12.09 volts on battery, is it finished?

[AD5OS]

2.11 for a grand total of 12.66 for lead acid batteries.

[bmxfelon420]

on a fully charged battery, the vehicle should only be running off the alternator. that way it doesnt tear up the battery.

I proved this by having my negative terminal come off while i was going down the road, and it still ran. My radio was cutting in and out sometimes though :O

[LawdoG247]

It's not the volts you should be worried about. Its the Cranking Amps.

[Ghostyman]

I proved this by having my negative terminal come off while i was going down the road, and it still ran. My radio was cutting in and out sometimes though :O

No, what you proved was that the car COULD run without the battery. By that same token, if your alternator died when you were going down the road, the car would still run until the battery died. Doesn't prove anything about how the car SHOULD run.

In a properly functioning electrical system, the battery and alternator are both being used at the same time.

When the car is running, the battery is receiving a charge from the alternator. There is no circuit that only provides power to the battery when it drops below a certain level. Get a multi-meter and test it yourself.

[90Haccord]

The alternator is supposed to charge the battery.

but the battery is not ALWAYS 100% charged at all times, I have a High output alternator and I still put my optima battery on a float charge once a month to "top off" the battery to make sure its fully charged.

I consider it being nice to my battery and MAKING sure its charged.


Its usually 85-90% charge and will take 1amp for 30 minutes before my charger says "FULL".


But I baby my car, it doesn't NEED to be charged, but using this method my optima orange top is on its 8th year(put in car in Aug 2000 when I bought it). Its now October 2008, I'd like to think me toping off the battery once a month helps. but I've heard they don't make optima's like they used too also. I've killed my battery about 7 times by leaving the headlights on.