Thread: Battery draining / Alternator or ??? Please help

When it does the "flipping out" did you measure the voltage of the battery? Specifically while cranking? Or before cranking.

If it was me I would check the battery voltage every morning before cranking. If it is low then start troubleshooting parasitic drain or insufficient charging. If voltage is 12.6v (fully charged battery) and you have trouble starting then troubleshoot bad or borderline bad battery. Measure voltage while cranking. If below 9.6v replace battery.

Parasitic drain test- Disconnect the positive cable while car turned off, insert an amp meter between battery and cable, and check for draw. If draw is over 100ma then start pulling fuses to figure out which circuit.

Don't forget to clean battery terminals and grounds. Stray grounding issues and poor contacts can cause all sorts of gremlins.

http://www.grandprixforums.net/threa...ue-please-help!

lets keep it to one thread

also an 04+ will draw more than 100 ma when it's just sitting.

Yeah something is killing the battery for sure. The thing that gets me is that it is something that is not controlled by the system or it would go into battery saver mode. A test light isn't really going to help as it will always light up since the system draws a few hundred milliamps. You should use a meter and actually measure amps. One with a 10 amp capacity would work. Basically the same test except you'll be able to see how many amps whatever device it is.

Jeff

Do you have an aftermarket radio by chance?

Ok, noticed a few threads that mentioned having issues where their batteries were dying overnight caused by a bad interface module for aftermarket radios.

Here is a parasitic drain test. Connect an amp meter between the positive battery post and the positive cable. Measure the miliamps. If it is excessive start pulling fuses to determine where the drain is coming from. On my 04 GT, aftermarket radio, I have a 16.2 mA drain. Normal...


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Originally Posted by brettstoner

Here is a parasitic drain test. Connect an amp meter between the positive battery post and the positive cable. Measure the miliamps. If it is excessive start pulling fuses to determine where the drain is coming from. On my 04 GT, aftermarket radio, I have a 16.2 mA drain. Normal...


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Okay, I,ll give it try. Turbocharged400sbc suggested that the care has an alarm and it could be disabling the starter? I'm thinking he might be right?