My battery is dead after the car sits parked for over 9 hours. I measured the current flow through the positive terminal at 2.4 mA, and pulled all the fuses and the drain stayed constant. A coworker suggested that the car has battery has bad plates internally and has drain inside it and should be tested,but the other day in cold weather, I accidentally disconnected the ignition Coil and did some 10 unsuccessful starts before I found the mistake, and she still had juice. Is it really possible i have a bad battery or is there a short somewhere else in the harness-which I find cant believe because the drain as i said is 2.4 mA

Are you sure you are reading milliamps. The reason I question the spec is that you wrote 2.4 ma and usually ma readings are not shown with a ".4" accuracy (.0024 amps). If the reading is correct, the draw is extremely small.What vehicle is this battery in? Do you know what amp/hour rating this battery is rated for? Is it a Mercedes battery?

The static amperage drain on a Mercedes is usually about 30ma at all times. This is for the clock. You can see it pulse on a meter when all is well. I'd start with a battery and see what happens if you don't have access to a tester.

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

I had the same problem and my mechanic asked me an interesting question. He asked if my power antena was working or not. I told him not and that it was stuck on open. This is what was draining the battery! eventhough it was stuck it was trying to bring it down when I turned off the car. So I cut the power to the antena and problem solved.

Good luck!

Carrameow,

You can take the battery by Sears, Autozone or any chain store that sells batteries and they will load test it for free. Sears has a very good smart tester that is very reliable. You've nothing to lose but a little time. I've seen batteries go bad and do as you describe.

.0024 Amps is not enough to drain a good battery in anything less than weeks.

Best of luck,

hmmmm Ive got the same problem and just posted it - but after reading this Im wondering if my antena is the problem because it doesnt work either! Ive noticed a lot of us sl owners have these types of problems with the car not starting after sitting for a while. Mine is so wierd that as soon as the chargers cables are attached to the battery the dang car starts!! Im at my witts end with it! Good luck to you.

I recently posted “Batter drain when parked” and found the problem to be the power antenna.

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Daryl Miller
84 380 SL
51 Ford
61 Chev 409 project
62 356
80 928
88 928 S-4
97 528
03 Forerunner

Since it drains in only nine hours, just disconnect the ground and positive cables, wait over night and then reattach them. If it is dead, then replacing the battery would be a good idea. If it starts up you have something stuck on which is draining the battery.

The positive cable will likely issue a small spark when you reattach it due to the clock draw, but if it is a robust spark with an audible snap, you have something drawing pretty heavy current.

You can begin looking for stuck items by examining the car at night in a dark garage. Anything glowing? I left my glove box door open one night and had a flat battery the next day. Other items are less obvious, like the antenna which would require you to remove the fuse to confirm. Do one thing at a time to isolate the problem area, starting with the suggestions others have made based on their experiences.

Good hunting...

230/8

If you ever see any battery that seems to be fully charged and can go dead from one good start...

It more than likely has a dead cell or two in it...

I was waiting for repair work to be done on my car one day, when this lady pulls in the parking lot...

She comes over to me and says her battery keeps going dead and will not hold a charge...

I asked her to restart her vehicle and you could hear the cranking speed go from good to bad... [one cranking session]

I told her you need a new battery, yours has a dead cell in it...

She went inside to see the mechanics, and one came out and checked her battery with [some unknown tool?]...

He tells her you need a new battery, yours has several dead cells in it...

Then he sells her an overpriced/overated battery and charges her for the installation and the previous battery check...

Had she gone to Wal-Mart they would have charged her only for the sale of a new "everstart" battery...

She could have saved @$75 USD...

A fool and their money are soon parting ways; Just how did a fool get any money in the first place..?

This may be a financially unsound approach but if holding charge problems occur when a battery is over 4 years old, I replace the battery. I don't check fuses or current draws or anything. Thus far it's fixed the problem for me every time.

Sixto
95 S420
87 300SDL