I have the factory ACDelco Battery. I was wondering if someone knew how much voltage the battery puts out. I wanted to see about how much RMS my amp is running. My MTX Thunder 801D is rated at 250 watts at 4 ohms at 12.5 volts and 400 watts at 4 ohms at 14.4 volts. The factory test sheet is a lot higher than the rated numbers.

Thanks

With the engine running, use a volt meter on the battery.

I have a voltage tester, but I don't think it is accurate enough to get a true measurement. It's the type with the positive and negive "pencil like" probes. Thanks though, I'll ask some friends if they have a good one.

If anyone else has done this could you post your results.

After the batter you will have 12 volts. Prior to that the altenator should be around 13.8 volts. If you are under 13 volts it is probably on the verge of giving out. A company will almost always use 14 volts for there tests.

If your sub can handle a 2 ohm load....that amp is rated to put out 800W X 1 at 2 ohms (14.4v) How many subs are you running?...because you wouldn't be able to get 800 X 2..plus if you put 2-2ohm subs then it'd be a 4 ohm load.