In the span of 2 days, i had a battery go from functioning to totally dead.

Truck wouldn't crank so i tested and found one battery to be dead. Bought a new battery, installed it and still the same, very weak engine crank. gauges and LP are working but the engine is not.

I know your supposed to replace 2 batts at a time, but i just couldn't afford to last fall so i replaced one, and the other one today.

Is it possible the battery is just dead from the parts store?? it was new in the wrapper. i put a charger on it and it deffinatly needs juice.

 

The unit will crank on one good Charged battery. As you know, one dead battery will pull a good one down to point of not starting. And you may have replaced the good but discharged battery and still be in trouble. ????????

 

It is possible for the store to load check the battery for you. It is possible to get a bad battery when you buy it off the shelf, but unlikely. Obviously, 1 bad battery will pull the other one down. It does sound like you are having some sort of charging issue, could be the alternator. Don't know how hard that is to pull, but you can also take that to the auto store and they can check that for you (NAPA for sure, autozone had a hard time with the big amp alternators in the diesels).

 

yes, i bought two marine/rv batts from wal-mart .
one was NG, even after charging over night.......so any more when i buy a battery i have them test it before i pay for it

 

Well i ran to checker last night and had them test my alternator.. It's shot. Ok i can deal with that.

My batteries both test at 12.9v but still will not crank the engine, so i guess i'm off to where i bought the battery.