I seem to be going thru a battery every 45 days or so. The charging amps on the alternator are within spec. I have checked all the obvious things like leaving interior lights on. I just don't have a clue. Could it still be the alternator even though it checked ok? Any suggestions would be very helpful. Thanks.

 

Yep, I'd swap the alternator and see what happens, Autozone will usually take it back if you don't gunk it up with grease.

Have you taken the alternator off and had Autozone check it. They do that for free you know. The only thing is that you have to take it off yourself and bring it to them.

 

How do you know that?

Remember that the alternator will put out what the battery and electrical system needs up to a point. The current will be different depending on the draw. If the battery is low, the current will be higher and then gets lower as the battery charges.

The easiest way to check the alternator output is with a voltmeter across the battery. When the engine is off you should be measuring about 12.6V. When the engine is running you should measure close to 14V. This shows the alternator is putting out currectly.

I think you have one of 2 problems assuming as you said the alternator is good. Either you have a bad connection and that is creating too high a resistance to properly charge the battery or you have a slow drain when the car is turned off. I'll put my money on a bad connection (assuming as you said the alternator is good). One way to check but don't let it fool you is to measure the battery voltage from the + battery terminal to the frame and then from + to the engine. Both ways should read the same as when you check across the battery.

The first thing to check is the 2 critical grounds at the frame and at the engine. Clean em up and tighten them.

Don't forget the positive cluster on the passenger fender.

With regards to a slow drain, have you installed any electrical components lately? I know those big thumping amps go bad quite a bit and create a draw on the battery when the car is turned off.

You can check for a current draw when the car is off by removing one of the battery cables and putting an ammeter in series with the cable. When the car is off you should not pull much probably like .1 to .2 amps. Remember the radio keeps memory and clock settings so there will be some draw all the time.

Sorry long. I just don't know when to shut up.
I hope I didn't put you to sleep.

 

that was damn good info if you ask me

 

Have you checked how many amps your starter is pulling when cranking?

 

See Scoob, I knew I would put you to sleep

 

Is it possible the RAP module is continuing to pull power after it's supposed to turn everything off?

 

Yeah, it's possible. Someone had that very problem recently. After about 15 minutes, it was clicking things on.

More info is needed like - what is the volt gauge reading while driving and idling? If there is no perceivable problems noted by the gauge, an ammeter should be put in series with the battery and watched for a while to see if something is pulling juice when the car is off.

 

I think the guy/gal that started the post bugged out on us.

 

I'm here. Had to go away for the day on business. I appreciate all your detailed info. Looks like I'll have to do some more testing. The Alt. was reading 14.2 at idle. I did not test it with the car off. In fact I did not know it would make a difference, but I guess i'll check again.

When I go out tomorrow to start it what happens is I get a single click when I turn the key, then a pause and then it will start. The starter was replaced 6 months ago. If I let it sit more than a day or two, it won't start at all unless I jump it.

 

Fred can you provide some info on how to test that?

 

*From you saying that, I would say that Rodriguez is right on key. You probably have a bad connection....*

 

Read my original post

 

Edit ^

 

Clamp-on DC amp meter.