M42club.com - Home of the BMW E30/E36 318i/iS

DISCUSSION => Electrical => Topic started by: 1991318is on September 06, 2007, 12:48:27 AM

Title: Dead Battery Gremlin
Post by: 1991318is on September 06, 2007, 12:48:27 AM

Mk, so basically my car kept on losing charge after day or so sitting, so I figured it was the battery. I checked the alternator, was putting out 13.6amps at the alternator, so therefore should be putting out the right amount of current. So I got a new battery, and now I just had the same problem after it sat for a day. Any ideas besides grounds, and which ones would you suggest first.

Title: Dead Battery Gremlin
Post by: sepehr on September 06, 2007, 04:24:42 PM

Your side mirrors? The heaters might be staying on.

Title: Dead Battery Gremlin
Post by: RED IS 91 on September 07, 2007, 08:25:46 AM

I stole this from another forum................:D

You probably already know this: you can verify if you have a drain with an voltmeter (in ammeter mode) (you can get this for $10 in wal mart)
Disconnect negative wire from the battery and attach it to positive post on voltmeter. Attach negative volmeter's post to
negative post of the batter. With this setup, any current that's flowing through the car circuits will show up in the ammeter.
On a normal car current should 0 or negligble (probably radio will draw tiny current, etc).

So, once you set this up and (hopefully) find that you have current draw, start poping out fuses one by one and watch for current to go down.

btw, don't try to crank the car with this setup, you'll fry your ammeter.

Title: Dead Battery Gremlin
Post by: 1991318is on September 07, 2007, 01:00:42 PM

Quote from: sepehr;33235

Your side mirrors? The heaters might be staying on.

Mine doesn't have side mirror heaters, and I know everything is off, I've triple checked.

Quote from: RED IS 91;33292

I stole this from another forum................:D

You probably already know this: you can verify if you have a drain with an voltmeter (in ammeter mode) (you can get this for $10 in wal mart)
Disconnect negative wire from the battery and attach it to positive post on voltmeter. Attach negative volmeter's post to
negative post of the batter. With this setup, any current that's flowing through the car circuits will show up in the ammeter.
On a normal car current should 0 or negligble (probably radio will draw tiny current, etc).

So, once you set this up and (hopefully) find that you have current draw, start poping out fuses one by one and watch for current to go down.

btw, don't try to crank the car with this setup, you'll fry your ammeter.

Thanks I'll give that a shot. I talked to the guy I usually have check my car out when anyone else touches my car and he suggested that the regulators are known to go bad, so I'm gonna test that tonight.

Title: Dead Battery Gremlin
Post by: 1991318is on September 08, 2007, 03:54:07 PM

Anyone know if the regulator is built into the alternator or not?

Title: Dead Battery Gremlin
Post by: ak96ss on September 08, 2007, 06:42:59 PM

I believe it is built in.