Alternater?

steiner_5000 · Post by **steiner_5000** » Wed Mar 14, 2007 11:42 am

Is my alternater bad? It's not charging my battery and my truck wont run with the lights on. So I took a volt meter to it and it only read 12.8 volts. I was taught in school that it needed to be at 14 volts. Is this right?

Post by **Nobody** » Wed Mar 14, 2007 6:02 pm

Doesn't sound like it's charging. Make sure all the wires are hooked up to the alternator. It's pretty common for one of the wires to pop off. Had it happen to me a few times.

You're local auto parts store should be able to test your entire charging system for free. Takes the guess work out.

ranger5.0 · Post by **ranger5.0** » Thu Mar 15, 2007 11:03 pm

12.8 volts tell me that you have a good charge. If you had 11.8 then I would worry a little. An easy way to tell if the alt is bad is to disconnect the positive wire from the battery. The vehicle will die if the alt doesn't have a charge. 11 volt to 13 is normal. Most batteries that are good are in the 12.5 to 13.5 range. I have yet to find one that puts out a full 14 volts.