Originally Posted by Multibeemer

Well, it's kind of a long, and somewhat embarrassing, story; I'm not even sure I have a problem, but I want to be sure, as it's primarily my wife's car, and I don't want to have her left stranded. I'll try to make it as brief as possible:

1. About a week ago, battery goes stone dead. No start, no lights, radio, nothing. Battery is six months old.
2. Take battery to get tested. Putting out 8.45 volts in fully discharged state. Way below spec. Suspect bad battery.
3. Have it charged and re-tested. Tests good!
4. Put battery back, but suspecting it's still not good, I leave the negative cable disconnected. Take it back to Autozone the next day to have it tested again and they find it's only 53% charged. They test it again in this state, conclude it is indeed bad, and they give me a new one.
5. Here's the embarrassing part. I drive home with the slip-on seat heater on, and forget to turn it off when I get home. Car isn't driven the next two days. Next time I try to drive the car, it's stone dead again.
6. Hook up a 2-amp battery charger to the connections in the engine compartment, and leave it charging a good 14 hours, but the charger never indicates the battery is fully charged, so I'm concerned there may be a parasitic leak, and it wasn't just the left-on seat heater that caused the battery to discharge. Thus my thread asking how to test the amount of parasitic leakage.

So that's the story. I'm still very confused about the battery drain test procedure. I've read I need a larger (e.g. 10 amp max) ammeter. Why? Mine only goes up to 250 mA, but I've heard the spec for parasitic current is only about 35 mA. What's this inductive ammeter JCL recommends? Is it expensive? Is it something I could rent? How is it used? How do I get around the need to have all the doors closed when I do the test, and the need to let the car sit for 20 minutes after closing them? Do I have to get in the car, crawl in the back to disconnect the positive cable, sit in the car for 20 minutes, and then crawl back with my ammeter to do the test?

Is it really this complicated? Could somebody please reply with a simple, step-by-step procedure on how to do this? Thanks.