Battery vs Stereo

[dochummer]

Interesting info f5fstop. My problem is that my battery will randomly die on me...pretty much over night. I have a yellowtop optima, and had it tested at a tire shop. They said the battery was good, just low on charge (11.78v), and the alternator was charging at 13.38v. I've had the air suspension module fixed previously, which took care of the problem for about a year...but now I've run into the same problem again... Any idea what would be the most likely to draw on the battery too much? I could pull the fuse to onstar - seeing as how I don't use it....

[f5fstop]

Have a reliable shop do a test to see how many amps (milliamps) are being drawn when the ignition is off, and after a wait of 20 minutes. Modules go into sleep mode after approx. 20 minutes, so the parasitic drain will go down. If there is a high drain, then start pulling fuses until the drain drops. This will tell you the circuit that is at fault.
It might be the air suspension system again.

The Onstar module draws an extremely low parasitic drain.

[kodiakz]

I have always proceeded on the 25ma or less draw to be safe. Believe it or not, the newer bcms are trickier than the old ones as any micro draw can keep them awake and kill the battery fast (learned this the hard way ). In fact, the new lan systems will draw upwards of 3 amps for up to 20 minutes after the car is turned off.