This is my first post in the forum. I bought a 2001 S500 8 months ago with 49,000 miles. I am having problems keeping the battery charged if not driven for a few days. I have replaced the battery twice now and continue to have the problem. I have heard that this is a common problem with S500's within certain years. Does anyone know how to resolve this? Thank you in advance for any suggestions.

 

check the alternator if its charging the battery. Then this is the hardest part you could have a power leak somewhere. Is there any aftermarket work done to car? NAV, radio? speakers? alarm? check those out. ur voltmeter is your friend.

 

I had my both Mercedeses sitting for 5 weeks and they started with no hesitation ON 7 YEARS OLD BATTERiES.
My friend installed aftermarket alarm on his MB and needs to charge battery every couple of weeks (it is his spare car) get battery maintainer.
$7.99 at Harbor Freight.
If you really want to do it, connect amp-meter between the battery and the car and start pulling the fuses. That will point to the direction of the current leak.

 

EIS, OCP, UCP and door control module current drain.

 

I have a 2002 s600 with 25,000 miles, the battery keeps going dead if i let the car idle at all, the car will die if it idles to long..
if any one can help, i have had the car to the dealer 4 times for this ...

 

Suggest you permanently wire in a modern "switched mode" trickle charger accross the battery.
Plug it in when you car is parked at home and you will never have a flat battery again.

Allan

 

the battery is good?

the alternator is charging well?