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2001 ML 320
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66 Posts
Discussion Starter · #1 ·
I have a problem where if I leave my car in the garage without starting for 3 days or more I have to jump it to start. It doesn't need much to start just a little boost.

I got a test light and took off the positive battery post and connected the light to the terminal and touched the post it lit up. I tried to remove all the fuses one by one, both inside and under the hood, but the light was still lit. I also tried this with the negative terminal as well.

I noticed that it on the positive it wasn't the main terminal that would light it up but the side wire that is connected to the secondary bolt on the terminal.

Anyone know what else it could be? I am lost...

Any help or ideas would be great. It is a 2001 ML 320 :beerchugr:
 

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1999 E55, 2001 E320, 1990 560 SEC, 2004 ML350, 2001 ML55, 1995 S500, 1998 SL500, 2010 E550 Sport zoo
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7,035 Posts
Time to get a new battery maybe

It may not be a new drain on the battery, the battery could be going bad..that would be my bet.
 

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'07 C280 4matic, '06 530i, '98 ML320
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zmanzbo, take the battery out of the truck and take it to auto parts place and have them test the battery with a load tester. Typically, they don't charge for this test. If your battery is on the border-line (on the way out), this test will tell you whether the battery is indeed going bad.

After the 'load test' if the battery is good, then you can diagnose further...
 

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Dallas, Texas
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11,482 Posts
I have a problem where if I leave my car in the garage without starting for 3 days or more I have to jump it to start. It doesn't need much to start just a little boost.

I got a test light and took off the positive battery post and connected the light to the terminal and touched the post it lit up. I tried to remove all the fuses one by one, both inside and under the hood, but the light was still lit. I also tried this with the negative terminal as well.

I noticed that it on the positive it wasn't the main terminal that would light it up but the side wire that is connected to the secondary bolt on the terminal.

Anyone know what else it could be? I am lost...

Any help or ideas would be great. It is a 2001 ML 320 :beerchugr:
First thing. Never get close to positive terminal unless negative is disconnected. Test light or volt meter are not a method to check battery drain. The only method is amp meter connected in series at negative terminal. Anything above 50mA needs to be investigated.

Of course have your battery tested first. MB does not recommend "load test" as it puts undue strain on battery and is only valid on fully (10 hours) charged battery. Their method is to use "reserve capacity" meter. Any battery with less then 50% reserve capacity is considered bad.
 

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2001 ML 320
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66 Posts
Discussion Starter · #6 ·
First thing. Never get close to positive terminal unless negative is disconnected. Test light or volt meter are not a method to check battery drain. The only method is amp meter connected in series at negative terminal. Anything above 50mA needs to be investigated.

Of course have your battery tested first. MB does not recommend "load test" as it puts undue strain on battery and is only valid on fully (10 hours) charged battery. Their method is to use "reserve capacity" meter. Any battery with less then 50% reserve capacity is considered bad.
Can you explain how to do these tests?

I went to the place where I bought my battery and they said there was 70% charge in it.
 

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Dallas, Texas
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Turn everything off, key out of ignition. Disconnect negative cable, connect amp meter between cable and battery negative post. Put meter on amp scale and look at reading. 0.050A or above needs to be looked at. There are some things that run after engine shutdown like aux water pump and e-box fan. Wait for those to shut off. About ten minutes.
 

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2001 ML 320
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66 Posts
Discussion Starter · #11 ·
So I took the truck into the dealer and here is what they came up with.

Tested battery output-good, tested for current draw-none found, found parasitic draw across top of battery. Needs battery, tray and acid vent and catch pieces.

So is this something I can replace on my own? I already replaced the battery on my own last year. It is still covered under warranty so I can get a new battery.

Do I need to replace the other parts that the stealer suggested?

Thanks!
 

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1999 E55, 2001 E320, 1990 560 SEC, 2004 ML350, 2001 ML55, 1995 S500, 1998 SL500, 2010 E550 Sport zoo
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7,035 Posts
Bad battery...

The battery is bad, the "parasitic draw" is a malfunction of the battery wich means it is discharging itself across the top of the plates, "won't hold a sufficient charge".

Since most after market batteries are a different dimension that the correct OE battery - you had to torque some shot, or twist some shit down to get the replacement battery to fit ?

If you have your battery replaced by where you bought it from then you might have the same problem (or worse/quicker) with the replacement.

If it's a bdget question - get the battery replaced by that store and go for another round.

If you don't want the same problem again, then get a OE equivalent, either from the dealer, or from Interstare - the correct OE battery will be exactyl the same dimension as the dealer battery - if you want OE equivalent sizes DOES matter here.

On the other parts, it all depends what you think, if they were twisted out by this replacement drama or not.

Sometimes you get what you pay for, but there are good OE equivalent betteries out there other than dealer (again though, size DOES matter).

Good luck !
 

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2001 ML 320
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Discussion Starter · #13 ·
Cool, thanks alot for the info!

I got the battery at O'Reily's and do remember having to jack around a little bit to get it to fit. Although they claimed this battery is specific for the ML.
 

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2003 ML 320: Engine:112942 31 305548, Transmission: 722662 03 807606, FrontAxelAL431020714752162233
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128 Posts
Zmanzbo what was the outcome of this? I have a ML320 2003 Base and its radio or MCS is the reason for the draw on the battery thus I pulled the F21 fuze so the vehicle will always start. If I put the fuse back in the vehicle is dead after two or three days. With fuse out I've left it unstarted for 30 days and can still start it.

I don't want to think its the MCS unit that is bad becuse it works fine with fuse in. I think it has to do with when the deal disconnected the analog phone system as an FCC requirement and the computer is searching for that phone system when the fuse is in.
 

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On average, with a fully charged battery, how long should the battery remain charged while sitting? I assume that there are components constantly drawing power from the battery even when the car is not running.
 

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2004 CLK 240 Coupe
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11,385 Posts
I've left mine for 3 to 4 weeks with no problems when working away from home. For longer periods of non-use, a tender charger is a good idea. You can leave it connected permanently and it will not over-charge.
 

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1999 ML 430
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417 Posts
Mine routinely goes 2-3 weeks

just sitting in the garage without the slightest ill effect; I'm sure it would go much longer. Really only whatever minor draw might come from the alarm, if set, and from the clock and maybe the presets, etc. in the radio, there's nothing going on to drain the battery.

I'd say if the car is going to sit for a month or more a good, as in smart, charge tender is probably worth it, and by "good," I don't mean the $29.95 one. It doesn't take many times of a battery being deeply discharged to get it sulfated so that it will no longer take a full charge.
 
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