The Problem: My battery loses charge after sitting for a few days. When starting the car, the starter turns over slow at first but picks up speed & ultimately starts after 5-10 seconds of starting. It's as if the battery is "finding power" (like the little choo choo that could). Thought I had a dragging starter, but everything works fine after I put the battery on a charger overnight.

Test I've performed:

1. Alternator: 13.5 volts
2. Battery test: put a load tester on it & it handles the load.
3. Battery draining while car is off: I checked draw on the battery while the car is completely off & it only shows 00.2 millivolts (not sure I performed this test properly - I removed negative cable & placed volt meter on postive post & negative ground cable (not post).

Strange symptom: There is a crack in the plastic housing around the positive post on my sealed battery. I caused this a few months back while seating (hammering) positive cable on post. Hammered way too hard .

My question: Is it the crack in the battery housing that is causing the battery to slowly lose power or did I perform the millivolt test improperly & there actually is a drain on the battery? I hate to go out & buy a new battery only to have it slowly die over time again.

I have no idea whether the crack has anything to do with the battery being toast, but it is for sure that the battery is toast if it won't hold a charge and there is no excessive drain.

Battery time.

Good luck,

chances are it has a short in between the cells.

Good luck.

www.benzbonz.biz

Marty

Larry - did I perform the battery drain test properly? I seem to remember an earlier post of yours on how to test but no reference on whether to remove the positive cable or the negative cable. Does it matter?

Actually I think you want to do the static current draw using the ammeter function of the meter.

Set your meter to 10A first, then go to a lower setting if you're below 1.

I never did this myself, but I think you don't want to see over 50 ma or 0.05A... 20 ma 0.02 A is more in the range of normal...

The people who recommended using the voltage function of the meter use a resistor in series with the battery lead, then use the voltmeter reading and Ohm's law to calculate a current draw through the resistor. I guess this method protects the meter from damage if you're drawing a lot of current.

Hope this helps, Bob

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Bob Roe
Lehigh Valley PA USA
1973 Olds 88, 1972 MB 280SE, 1978 Datsun 280Z, 1971 Ford T-Bird, 1972 Olds 88, 1983 Nissan Sentra, 1985 Sentra, 1973 230.6, 1990 Acura Integra, 1991 Volvo 940GLE wagon, 1983 300SD, 1984 300SD, 1995 Subaru Legacy L wagon, 2002 Mountaineer, 1991 300TE wagon, 2008 Murano, 2007 R320CDI 4Matic 52K, some Hyundai, 2008 BMW 535xi wagon, all gone... currently
2007 Honda Odyssey Touring, 2014 E350 4matic

The easist way to check for a battery drain is disconnect the negative battery cable in the evening. the next morning reconnect the battery. If the car starts normally, then there is probably a drain in the car. If rhe car doesn't start or starts slowly, then the battery is at fault.
Try it and let us know what happens.

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84 500 SEL (307,xxx miles)

When doing a current draw test it does not matter whether you remove the positive or negative cable as long as you put your ammeter with proper polarity in series with the circuit. You are using the AMMETER function NOT the voltage function.

I did not read your original post carefully enough. You need to do this test correctly using the ammeter mode.

Have a great day,

if there is a crack in the case good chance the interior straps are damaged.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

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One of the old tricks to "wake up" a battery is to turn on the headlights for 5-10sec. I don't know why, but it works, especially in the winter. Using the glowplugs does the same thing.

If your battery isn't sealed (has removable caps), then check water level - plates just covered with distilled water, pull the cables, trickle charge overnight, check the cells with an el-cheapo hygrometer, let it sit a day, then check it again. That will tell you if the battery's holding a charge. Some sick batterys will recover - I had a 6volt tractor battery that recovered after alternating trickle charge for a day and sitting for a day. Took a week but it recovered.

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daBenz - 1970 220D