If I don't leave my car on the battery tender the battery will die in a day or two. Decided to try and track down a parasitic drain. Searched the forums and found out how to do it with a multimeter with the neg battery cable disconnected. It immediately showed 12.67 volts. Started pulling fuses and it never changed. Went back to the battery thinking it was my amp wire. Pulled it off and still no change. So I started disconnecting wires from the positive post and the volts finally dropped. Turns out it was coming from the wire going to the alternator. Should my alternator be pulling 12 volts with the car off? I'm pretty sure that's not supposed to happen. The alternator is only about 1 yr old, but I never drive the car.

 

Try testing the starter - sometimes the solenoid spring will not retract all the way and put a severe drain on the battery

 

You need to check the current draws, not the battery voltage. The battery is large enough that the voltage will not immediately sag or rise because of a small drain. The reading you are showing is just the voltage of a fully charged battery. Now if you put your amp meter in series with the positive lead or from the negative terminal to ground (with the lead disconnected) or in series with the lead, then you can monitor the current drain while you pull fuses and disconnect stuff to find the problem area.

 

That was by checking the current draws. The voltmeter was in a series between the neg battery cable and the neg battery post. I pulled all the fuses and the reading never changed. When I removed the positive wire that goes straight to the alternator the reading changed. So it looks like the alternator is pulling a 12 volt draw when the car isnt running. Im trying to find out if this is normal.

 

Amps, man, amps (like Kevin said). You can't check a draw using the voltage scale.

 

Damn. Im an idiot. Must have overlooked that when I was reading the post. Ill have to check again when I get off work.

 

One thing your volt meter is good for is a check of whether your alternator is putting out when the car is running. Just put it across the battery and it should be above 13.6 V at a fast idle. If you really suspect it is draining the battery, you could disconnect it at the back - both cable and sense wires (careful not to short the cable), and check the car a couple days later as you have been doing.

 

Finally got a chance to look at the car, of course the battery was dead again. So I jumped it to get it out of the garage. Drove it for 30 min and shut it down. Tried to start it again and the battery was dead. So I got the it tested. Bad battery. Had a 3 year free replacement but of course the battery was 3.5 years old. Got a new one and took it home. Hooked up my mulitmeter and checked the AMPS this time. Meter showed .06 the entire time with the doors shut. Started pulling fuses and the amps dropped to .00 when I pulled the courtesy light fuse. Opened the door and it jumped to .02 pushed in the switch in the door jam and it dropped back to .00 So the courtesy light circut is what's pulling power. Checked all my interior lights, console, and glove box. Nothing is on. Even pulled the bulbs to be sure. Not sure what else to check? I thought that it should be showing .02 -.03 amps max. I also have a small Amp for my radio that when hooked to the battery adds .01 so I now have .07 total when the car is off. What should I check next? Why is that one fuse showing .06? Isn't he BCM on the same circut?

 

The quiescent current drain (sleep mode - keyless entry circuit .002, voltage regulator .001, pcm .010 max, head unit .005 etc.) is supposed to be about .020 - .025A total with the car just sitting there, but retained accessory power does stay on for 10 minutes or so if the doors are not opened (you are sitting in it after turning it off), the relays are drawing power during that time. I think it stays on for another 35 s after the doors are closed. Maybe that is getting in the way of your troubleshooting. Even possible the RAP module isn't shutting off when it is supposed to. So that circuit is always hot, but the power accessory fuse is after that, so not sure what all is draining your battery if nothing is on. Look also at brake light switches and stuff that works when the ignition is off. Maybe double-check your stereo amp if that is always hot - I've known more than one guy to kill his battery with aftermarket stereo equipment.

 

Did you figure out the source of your battery drain? I'm having the exact same battery drain problem, also tracked it back to the #8 courtesy fuse. I've been suspecting it's a bad BCM (having other issues with it) for the time being, I have been pulling the fuse every night to save my new battery.

 

Not exactly sure what was causing the drain. I read that sometimes that if the 3rd brake lights are burnt out they can cause a battery drain. Mine were burnt out. Replaced them and now after my car sits for about 20 mins it shows .01. With my new battery the car starts right up after sitting for a week without a battery tender on it.