Click to go to Forum Home Click to go to maXbimmer Home

Go Back   maXbimmer Forums > maXimum Tech > 3 Series > E30 (1983 - 1991)
User Name

Welcome to!

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

Thread Tools Rate Thread Display Modes
Old 06-29-2010, 05:03 PM   #1
2nd Gear Member
Join Date: Dec 2008
Location: Toronto
Posts: 223
Common battery drain items to check?

Seems like my car battery keeps draining out every 3 hours anyone know of any common areas that might be the cause in e30's?
BMWnoob is offline   Reply With Quote
Old 06-30-2010, 10:17 AM   #2
if I lived . I would be ~
everlast's Avatar
Join Date: Mar 2004
Location: Ottawa
Posts: 5,847
3 hours suggests a light that's on. Pull the bulb from the trunk and glove box first.

Barring that, get a cheap multimeter and do an amp test on each fuse. So, you put the meter into ampere testing mode, pull each fuse and stick the leads into where the fuse goes. You will see the number of amps (or milliamps) that circuit is drawing.

(The ghetto way is to go out at night, and pull each fuse slowly looking / listening for a spark. Big spark = large draw.)
everlast is offline   Reply With Quote
Old 06-30-2010, 09:01 PM   #3
EX E30 M3 Owner
Robb's Avatar
Join Date: Mar 2005
Location: North York
Posts: 2,504
could be a number of things... but check these

- Check alarm system (if you have)
- Car Amplifers can drain a battery (bad/leaky capacitors) if you have
- Trunk light, Dome light, glove box light
Robb is offline   Reply With Quote
Old 07-01-2010, 06:54 PM   #4
6th Gear Member
supernaught's Avatar
Join Date: Aug 2006
Location: Peterborough
Posts: 1,327
Send a message via MSN to supernaught
I've got a slow drain but my meter only shows a draw of 15mA. I don't see how that tiny draw can kill my battery in 5 days. I'm going to swap out my alt. Hopefully that does something. But 3 hours must be something significant.

88 325IX TOURING DiamantSchwarz|89 325IX AlpinWeiss|88 325IX DiamantSchwarz
supernaught is offline   Reply With Quote
Old 07-01-2010, 08:55 PM   #5
if I lived . I would be ~
everlast's Avatar
Join Date: Mar 2004
Location: Ottawa
Posts: 5,847
If you can't find anything fuse by fuse, then check draw right the battery. Check the alternator by checking voltage at idle with all electrical load, like lights, defroster, etc. It should be at least 13.5V, more like 14V is better.
everlast is offline   Reply With Quote

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump

All times are GMT -4. The time now is 01:17 PM.

Powered by vBulletin® Version 3.8.10
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Maxbimmer Copyright 2001 - 2018