View Full Version : New Battery, loss of voltage overnight


sciontc_mich
12-07-2009, 01:56 AM
Had to get a new battery since the stock battery was failing the load test. The new battery when new was 12.6volts and yes it did pass the load test.

But this is odd. When the battery has sat overnight and I read the voltage it's 12.44volts. I've checked the alternator and it's charging correctly. What would cause a battery to lose 0.14volts overnight? Is the battery bad? I was wondering if it was that emissions pump that runs for 5 minutes after 5 hours of sitting.

Someone help me out here, I really need the help.. thanks

L337Biker
12-07-2009, 04:35 AM
There's always gonna be voltage drain on a battery. Your factory keyless entry system is always using power, not more than a few mA though. Also if you have an aftermarket alarm this will also cause a drain on the battery.. not enough to kill it overnight though. Any aftermarket electronic equipment installed?

sciontc_mich
12-07-2009, 04:48 AM
There's always gonna be voltage drain on a battery. Your factory keyless entry system is always using power, not more than a few mA though. Also if you have an aftermarket alarm this will also cause a drain on the battery.. not enough to kill it overnight though. Any aftermarket electronic equipment installed?

Thanks, I finally found it, was a door ajar warning light! I had a "doh!" moment. lol so that's where the 0.16v went to when i tested the battery with a multimeter, makes sense for an led light. Once I fixed that, then tested it back up to 12.54, 12.55, up to 12.6, so yep I think it's fine.

Nope no aftermarket equipment, just stock, but I found the drain.. thanks again.