Battery Drain

Post Thu Nov 09, 2006 8:24 pm

Hi my 1992 325 cab is killing its battery over a few days. I have done a search on here and found how to check from the neg side of the battery to the battery lead. I have tested and on my meter it shows 00.0 set on DCA / 200m. Am I using the right setting or is this normal for it to show 00.0 when the battery lead is disconnected
Cheers, Andrew

Post Thu Nov 09, 2006 9:32 pm

All E30s should draw some current when you test between the battery negative and the disconnected lead. 30mA is typical, up to about 90mA.
If you get a reading of zero, then you're doing something wrong, or have blown a possible fuse in the meter.
Be carefull not to lock yourself out of the car with the keys inside when you do this!

Post Thu Nov 09, 2006 11:15 pm

It is probably the boot light - remove the bulb until you find a proper method (usually a cap) to make the switch about 5mm longer.

Also bear in mind a car battery takes very very few total discharges to kill it, but fix the problem before buying a new battery!

Post Sat Nov 11, 2006 5:39 pm

Right thanks for the replys. I have checked all interior lights and they are all fine. I checked the fuse in my meter and it had gone, but now when I check it I get ( 1 . ) on the meter and thats it. I tried pulling all the fuses but it just stays on ( 1 . ) anyone got any ideas?
Andrew

Post Sat Nov 11, 2006 8:56 pm

Is 1. on your meter an overload indication? Try it on a higher range.
Next thing to do is to remove the two smaller red wires on the battery + terminal, one at a time, and see if this affects the drain.

Post Sun Nov 12, 2006 12:02 pm

Right checked again, The next reading on my meter is 10a it shows 0.09a on this setting got it down to 0.01a when I removed the red small lead off the side of the battery + terminal. I followed the red lead into the fuse box it seems to be the main power for the fuse box, I then pulled all the fuses again still no change stayed on 0.09a. Next I pulled the fuse box apart and found the red lead coming from the battery was connected to the board and another red lead which looks like it goes back into the car when i took this lead off it went back to 0.01a. Anyone got any ideas
Thanks again, Andrew

Post Sun Nov 12, 2006 1:59 pm

Red lead going on is heading for the ignition switch, but hang on a bit before you reduce your car to a pile of parts!
You have a drain of 90mA, which is at the upper end of what is normal. Would take many days for a drain of this level to pull down a fully charged, healthy battery.
I suspect that there is aftermarket equipment of some kind connected to this red lead somewhere though.

Post Sun Nov 12, 2006 4:56 pm

Thanks Brian, After I last posted I moved the car from the garage to the drive and checked it again it was showing .22A now . I removed the glovebox and found that if I pulled the plug shown in the pic it went back to.09A. The alarm loom has been put on to this plug, with it pulled I can still use the car but the alarm and the locking wont work even off the key, so I will leave it off and see what happens. I think it could be the alarm
Thanks, Andrew