Benz-E-r

Searched the forum but could not find a thread that matched this. Feel free to hit me with a clue-X-4 if I missed it.

My wife's 2004 E500 wagon had the battery go several months ago (my 2003's is still going strong). Her car only gets used for short hops so figured the constant drain/charge killed the original battery.

Replaced the battery and the car has been fine since. I used the car myself yesterday, no sign of low battery. She calls me this morning saying her battery is completely dead. Not even dash lights up. She called Merc service to come and jump start it but I am concerned that something else is wrong and draining the battery since this has occured again in less than 1yr with no change in her driving behavior. Car of course is now out of warranty so if I have to take it to the dealer I am looking for precise things to have them check and not waste time and $$ on their usual trial and error.

Anyone seen this before or have pointers for what to check for unreasonable drain or may require a reset? When I get home tonight I'll probably be showing her how to use the charger/loadtester.

amdeutsch

There was an issue with the alternator/regulator that caused MB to issue a TSB. Might search for that on here.

There was an issue with the alternator/regulator that caused MB to issue a TSB. Might search for that on here.

There was an issue with the alternator/regulator that caused MB to issue a TSB. Might search for that on here.

There was an issue with the alternator/regulator that caused MB to issue a TSB. Might search for that on here.



Repeated 4x per OP's request.

konigstiger

Most common cause alternator/regulator malfunctioning. Have them check VMI to see if your vehicle is included in Service Campaigns 2005070017 & 2005060008. In addition, mention bulletin S-B-54.10/162 and suggest they perform a quiescent current test to identify if any closed circuit systems are responsible for voltage drop that may be draining the battery.

ss3964spd

Given the information and symptoms as described above I think there's something else amiss. Car had been fine since battery replacement, used the previous day with no issues, then completely dead this morning.

The system provides warning of a depleated battery(s). Unless the computer completely shuts down power to everything when BOTH batterys get below a certain level of charge then surly the interior lights would illuminate, the dash lights would come on, there would be some sign of life.

Dan

Benz-E-r

Some good suggestions, I'll have to follow up on the regulator service campaign. I believe the car had at least one of the regulator services performed.

The car started right up tonight when I got home, my wife had called roadside assistance and they jumped the car, "reset something" as she says, and she only drove it a few minutes before parking it in the driveway, not really enough to fully charge IMO. A few hours later she was able to start it and put it in the garage.

I'll check it again in the morning and put a load tester on it. I still wonder if the backup battery is the cause. Will post more tomorrow.

Benz-E-r

So battery dead again this morning. Completely dead. Battery read 0.0v on an external tester.

Put a fast charger on for a few minutes then switched it to start and started the car. MFD voltage display showed the expect 14+- volts from the alternator and gave the "disabling convenience features" message and electronics did not work for a couple of minutes as expected.

Car was left running for a while (10-15 minutes) before my wife made a couple of errands, not more than a few miles with two stops. No problems starting the car.

She will check the voltage via the MFD later.

One question, it appeared that settings like the radio were still maintained which to me means SOME voltage must have remained from the backup battery is that correct? If main battery is dead again I need to check the voltage on the backup battery, just did not have time this morning.

Barry45RPM

Remember... continued deep discharge then recharge by charger will kill the new battery. They're not made for this kind of cycling use, so delaying a repair will cost you a new battery.

Freshly

I kno im digging up old trash, but did you find a solution to this? The same F***** thing is happening to my 03 E500. My battery is dead every few weeks. MB comes and jumps the damn thing and then it happens 2 weeks later. It usually happens when I park the car over night and retrieve something from the car while it was parked (unlock, open a door and lock the car again). Its the most annoying thing ever

desired_speeds

does your alarm siren work?

Freshly

Ya it does, it died completely again last night and I couldnt even unlock the door. I used the key to unlock it and the alarm went off.. Why cant the other battery use its power to start my damn car instead of blasting the alarm? lol

ydlee

I have the same problem here on my 04 E500 and I just put a new OEM mercedes battery, I dont drive it much just to the gym and back because I commute in another car. Debating if I should buy a new BCM and get it installed??

vettdvr

watching for the solution.