View Full Version : Current Drain

07-11-2006, 12:51 PM
Hey all,

My battery is going dead over a period of about 2 weeks. If the car sits (which is does a lot) for 3 or 4 days it starts very slowly. I have a new crappy tire battery that I put in because I threw my good BMW battery in the daily driver.

Here are some weird things:

1. total parasitic drain appears to be 130 mA.
40 mA is the new stereo (no caps btw)
60 mA is coming from fuse 21, and I can't determine what it is (wo/ radio)
25 mA is fuse 28, can't figure it out either

2. car charges at 13.97 to 14.04 volts, which is perfectly in spec, however, the Canadian Tire battery is a maintenence free which needs 14.5, instead of the maintenence type from BMW which only needs 14. Hmm. I read this on the net.

3. Once, with the BMW battery in last fall, i left the two interior lights on for 2 days. The car started without a problem. Those two lights take just over 1.1 amps, as I measured last night. So, it stands to reason the battery is not strong enough.

4. Two weeks ago, the battery was nearly dead. I boosted for 1 minute with my booster / charger, started the car and was putting the charger away when the car slowly started to sputter, sputter, then died. The battery was too low to start it again. I charged for 2 hours then started, no problem. I immedidately thought alternator but it still show 14v all the time, under load or not.

I'm leaning towards the new battery having a short in one cell. My charger sometimes has problems charging it when it is really low.


07-11-2006, 02:27 PM
could be a bad bettery... bring it back and get a new one...

07-11-2006, 02:28 PM
130mA and it's killing your battery? It sounds like a defective battery.

I've got a CT battery in my car and I've never had an issue even after zero movement/ignition for over 2 weeks.

I left my parking lights on ONCE for 3 days and the car still started only slightly "slower" than usual.

I think CT will test the battery for free if you take it to their service counter.

07-11-2006, 02:43 PM
Thanks guys, I will take it in and see what their tester comes back with. I still have the receipt and the warranty card, too.

I had a CT battery in my 540i. I was shocked to see they had one that fit (the only applications were 540 / 740) and it was huge.. All the guys at the counter were astounded at the size of it. I should see if they have any more.. it would just fit in the e30 rear spot. :) The 5er had 320mA of drain for the first 5 days, then it would shut stuff off to conserve the battery. Cool.