Thread: What specific voltage do you read for the battery with the engine off?

The battery has been resting for days, and even had some drain due to cranking (but not starting) and lights and testing. After all that it was still reading 13.65 volts.

I'm dealing with the Honda from hell right now.

Weird, what kind of battery?

just went thru a mess with a 98 ford ranger....

new alt,batt,starter...

car off 12.2 volts.....running 14.3-14.8

Does the car run? What does it charge at while running?

I forget. Dupont? Some name brand lead-acid battery with a sticker that says it's from March 2009.

The car ran as recently as two weeks ago, but it does not run now. I'm finding out that the airbag control module (SRS Unit) has been dead for a long time and it likes to blow tons of fuses. Just recently the ECU also crapped the bed, so it's not running right now to say the least. =]

I'm going to get a new ECU for it (and maybe SRS unit too) and have the battery and alternator checked out. I'm guessing I'll probably going to have to replace the alternator at the least.

it would be a bandaid, but wouldn't adding a capacitor keep voltage spikes from occurring?i would definitely change out the alternator and maybe even the battery for safe measure... you don't want anything else to blow..

I don't think it's voltage spikes that are the problem, I think it's steady state high voltage. Either way, I'll get it fixed right and rescue a Civic from what would have been certain death in someone else's hands. Too bad we overpaid for it seeing all these problems now. =/

Yeah that's weird. You could tell for sure if you were able to check the voltage while running, but I admit that 13.5 is high for a battery that's been sitting for a while. Alot of alternators put out high voltage(I've personally seen 18v) as they're going out, so hopefully that's all that happened.

I would almost try and discharge the battery a little bit, Either use a head light or some other source of low current to draw some out of it down to about 11.5V, then trickle charge (3A) it back up to 14.4. This should recondition the battery a little bit and help prevent any damage.

Adding a cap will do nothing. What you need is another rectifier for the alt so it keeps the voltages down.