Current leaking,

[moon161]

What a mess, there are coulombs all over the floor!

Anyways, I diagnosed the dead flat battery that left my 240 D blocking the driveway yesterday morning. Easy way to get your wife yelling, tell you that much.

Anyways, charged up the battery, stuck it back in, multimeter shows 2-1/4 amps at 12V w/ no lights on, no key in the ignition. Didn't see any lights on. Now I pull the positive cable off when I park for a while

Any usual suspects on that? My plan was watch current draw and pull fuses till it stops, follow the circuit from there.

[Novice]

Use to be with the old generators when the voltage regulator went bad it did that.
Don't know if alternators are capable of the same thing of draining the battery.

[NoCalMer]

My power antenna did that to me once.

Hook up the meter and watch it. Start pulling fuses one at a time until it drops. Then see what is on that fuse which causes it to drop and start narrowing it down.

[turbobenz]

Nice coulombs

[Oracle12345]

year of the 240D?

do an amp draw test in series on your battery and pull one fuse at a time unitil the amp draw is 30 miliamps or less

[moon161]

Originally Posted by Novice

Use to be with the old generators when the voltage regulator went bad it did that.
Don't know if alternators are capable of the same thing of draining the battery.

High 13's at idle 14- 15V or so revved

82 240D

At no voltage, resistance across cables showed open ckt. But put 12V on it, 2.25A flows, that works out to 5-6 ohms. Hmm.

[Jeremy5848]

A recent similar problem (posted within the past month or so) turned out to be the power antenna. You can unplug it in the trunk. That would just about match your measured current drain and is an ideal "hidden" leak since nothing shows.

[Oracle12345]

Originally Posted by moon161

High 13's at idle 14- 15V or so revved

82 240D

At no voltage, resistance across cables showed open ckt. But put 12V on it, 2.25A flows, that works out to 5-6 ohms. Hmm.

Did you measure in series? measuring amp draw in parallel will give you bad results.

[Sbean]

I think I remember reading somewhere here that a bad alternator diode can do this.

[moon161]

Originally Posted by Oracle12345

Did you measure in series? measuring amp draw in parallel will give you bad results.

Yup, series, ground cable on the battery, ammeter between positive terminal and positive cable.

I'll check that antenna.

diode:
I donated my old volvo 240 to a friend for an enduro race. I knew I shoulda had him pull that alternator, it was new. Not real easy to get at, especially w/ a front end hit tho.

[blackestate]

If the regulator is bad, and the alt. is the source of the drain, then if you hold a wrench at the front pully of the alt. it will lightly pull the wrench due to the magnetic field.

[RML]

I just had this problem on my 84 and traced it to the antenna on fuse #2 IIRC. I was wondering if it had anything to do with my aftermarket Kenwood radio. Or if I leave the power antenna switch in the off positon if it would make a difference. I havn't had time to go back and mess around with it. In the meantime, I just have the antenna unplugged in the trunk. I also installed a quick disconnect on the negative battery post to make things a little easier.

I tested my 85 and found the same current draw. Hmmm. I conculded that either
a) 2.5 amps of current draw while everything is off is normal, which doesn't seem to make sense, or
b) I have the same problem in my 85, which seem like quite a coincidence.

When you unplug your antenna in the trunk and go back to take a reading on the current draw, make sure you either close the trunk or take the bulb from the trunk light socket. Otherwise you will be reading the current draw for the trunk light.