hi
i am a new MB owner and new to this forum too. i have a c320 and started having battery drain problems in december last yr. i had to finally change my battery. but the problem still percists. it seems like there is a leak in the battery and the circuit is being grounded somewhere. however i have, only a few months ago spent a lot of money on fixing other issues with the car and am really wary of spending any more dough on it. i can take it to the dealer and have them look it up - but i know that will be really expensive. i am trying to figure out a cheaper alternative.

one thing i am considering is to put in a battery recharger - perferably solar.has anybody had a experience with these.here are my questions regarding this- one big thing is how to connect it to the battery. this thing does come with the option of plugging it in to the cig. lighter. however, the C320 i have - once the key is taken out the cig. lighter is cut off from the circuit. so i figured if i have to use this option i have to keep the key in turn it to the 1st position so the lighter is in the circuit. but with this i dont know what other systems will also remain on and will they discharge even more from the battery????

the other option is to directly connect it to the battery. this is possible and the solar unit would need to stay inside the car. however,i am not able to find a way to pass the cables from the cabin are to under the hood. do you think it is possible??? if yes please tell me how???

i will highly appreciateany help on this subject. sorry for the long message and thanks for reading it. i am in a real desperate situation and would be very thankful for any and all the help u guys can offer.

thanks again,
aj

 

your car has issues with the seat control modules under the seats. the bad part #'s start with 203 the good part #start with211. look under the seats and look at the seat control modules you might need a mirror to see the bottom of the units but that could be your drain problem.

 

Ajay

I don't think your solar charger optionis going to work. I bought one for my MB 220 recently, and found (as you did) that it won't charge through the cigar lighter, as this is wired through the ignition. You can connect it directly to yourbattery, but you have to disconnect it every time you start the car, or else the power surge will damage the photovoltaic cells in the charger. This is too much of a chore to be of practical benefit.

A new battery should be good for 4-5 years. If you've recentlybought a new one, and that isn't holding its charge, it's worth having a specialist auto-electrician check it out. Find an independent, who won't charge MB prices. It could be that your alternator is not charging properly, and the cause could be something as simple as a slipping drive belt.

Jonathan

 

i had the same problem i took it into theMB dealership and they replace the battery but the real problem was the rear SAM system was out it is spendy to correct but i was under warrenty so it was free hope that helped

Brian

 

I'm curious:

What's the best way to keep your keep in good order...

should you fully charge it than drain it or should you try to keep it plugged in most of the time?

I ask this because in a month's time my battery (according to coconut battery) went from 100% capacity to 96% in ehhh, 20 days i think?

At this rate, i'm going to be "hurting" down the road hah

any suggestions?

 

Try this first:
https://mercedesforum.com/forum/mercedes-c-class-10/battery-draining-out-overnite-36825/

Gibb's problem solved.-

 

i had the same problem with battery drain and discovered that the seat modules go faulty.£644.00 at MB to replace but later found out it is simple to just unplug the module and just reconnect if you want to ajust the seats and save the money,hpoe this helps

 

+1 more for seat control modules. Have an 02 C320 and had the same problem, new battery and all. Seat control modules were the prob. Check the part #'s like stated above