Parasitic Drain - HELP! Pt2

[EDirty325]

1989 325is Coupe

Based on advice from a previous thread, I was able to trace a .03A drain on my battery to fuse 27 in the under hood fuse panel. I used http://www.r3vlimited.com/board/showthread.php?t=60297 to determine that 27 is either interior lighting, central locking, OBC, or radio amplifier. .03 doesn't seem like much, but it's definitely killing my battery slowly over time. So I had the battery tested (good), got a fresh charge, hooked up my volt meter and went to work pulling fuses, hoping it would drop to 0.

I pulled all fuses and the .03 draw never dropped until I pulled fuse 27, and even then it didn't go to zero, rather .01A.

I started by removing the OBC because I noticed it stays lit with the clock showing even when the car is off. This was causing .01 of the drain, so the amperage dropped to .02. I assume that .01 is an irrelevant amount of draw and therefore the clock was meant to stay on from the factory?

I made sure all interior lights were off, verified that there was no radio amplifier (in my trunk, at least) and pulled and unplugged my head unit, all with no change to the .02.

Questions - Do I possibly have an amp located somewhere other than the trunk? Or can my central locking system somehow be creating this draw? I'm not sure what exactly fuse 27 is used for, but to have narrowed it down to these 4 things, I've tested all but the central locking system. PLEASE HELP!!! Sick of carrying around a 13mm wrench to disconnect the battery terminal every time I park

[AndrewBird]

.03A (30mA) would take months to drain your battery. This is not your problem. I would check to make sure your alternator is charging properly. With the engine running, you should see about 14v at the battery, roughly 12.5v with the engine off.

[EDirty325]

.03A (30mA) would take months to drain your battery. This is not your problem. I would check to make sure your alternator is charging properly. With the engine running, you should see about 14v at the battery, roughly 12.5v with the engine off.

Yeah it took months the first time.. It doesn't kill it overnight it's just a slow drain. I put brand new brushes and a new solenoid in my alternator last September when I bought the brand new battery so I'm pretty sure the alternator is fine. Not to mention when the battery was dead last week I was able to jump it and drive no problem. It was when I turned the car off that it died again but I'll test it just to make sure. So essentially the battery has been slowly dying since September 2014 and I drive it maybe once or twice per week.

[AndrewBird]

You could always install a battery cut off switch if you don't drive it much.

You should also always charge the battery back to full with a battery charger when it dies. The alternator is designed to maintain the battery and charging from dead puts a big load on it and can kill it.

[EDirty325]

You could always install a battery cut off switch if you don't drive it much.

You should also always charge the battery back to full with a battery charger when it dies. The alternator is designed to maintain the battery and charging from dead puts a big load on it and can kill it.

Yeah when the battery died I took it out and had it charged and tested. I'll resort to the cutoff switch if I can't hunt down the drain.

I posted this thread to see if anyone knew what exactly that fuse was used for, and if they had any ideas as to how my locking central locking system could be causing it. Or if it was something that I had missed. I guess no one has any ideas

[Gregs///M]

30ma is about normal for most cars including the e30. If you do not drive your car much, you should have the battery on a battery tender.

[EDirty325]

Okay, alternator is putting out 13.85V so it's good, battery is still at 12.75V with the car off. If 30ma is normal, the only thin I can think of is that I let it sit for about 4 weeks and we got two snowstorms during that time. Either way, a good battery should be able to handle that. I have the same brand battery in my DD for 4 years now not a single issue. I'm nervous to keep the battery connected now but I guess I should just to see if it does again 😒


Sent from my iPhone using Tapatalk

[keefy6]

Mine ended up being a few wires loose on the right passenger side where the door hinge is. Also the passenger dome light was drawing a charge all the time...and, we found a small wire wasn't connected from the alternator. It actually started around January..

I had purchased and installed new Evo plug wires (which was required because of a bad connection on the spark plug connection), new distributor, two new batteries and a new second alternator. Turns out I may have spent a lot unnecessarily and all the parts could have been working properly, but works out in the end because new OEM parts are always well great.

Diagnosis of the batteries however, were being drained like a faucet so there was something somewhere and I just had to get it corrected and done correctly.

Luckily I found someone with experience in E30 electrical problems as such.

[ecsk]

No car will have 0A draw, as Greg said 0.03A draw is normal/perfect. I'd say your battery is just not good enough to hold charge.

[EDirty325]

No car will have 0A draw, as Greg said 0.03A draw is normal/perfect. I'd say your battery is just not good enough to hold charge.

The battery tested good under load and has kept a full charge since disconnecting after driving. How long would an E30 normally have to sit for it to get to a point where it wouldn't start? I think mine sat for about a month in the snow, so hopefully that's all it was.

Guess I need to drive it more :D