LOVEMYBS

My BS spends a lot of time in my garage. With the upcoming change in seasons it will spend a lot more. I searched the archives to determine if my BMW battery tender will work in my car. I know it won't work in my SL but thought it might in my BS. Does it also have dual batteries (start-up and electronics)? It's the cigarette lighter plug-in type. Anybody know? Thanks

Jim Brady

Check owners manual p324, the car's equipped with a charge maintence interface but you'll have to buy the charger.

alexander stemer

Mine did not. I wound up with a dead battery, so I bought the Benz charger. You do need to be careful, as it once seemed to drain the battery, which I thought might be due to not fully pressing the charger into the receptacle.

LOVEMYBS

Thanks, will do!

LOVEMYBS

I just ordered my battery tender from MB. It's $142.00 in their accessory book. It charges the battery through the cigarette lighter. Strange that my OEM BMW charger won't work. Oh well, it will work on my wife's X3 so not all is lost! Thanks to all who responded to my question for the feedback and info. This board is GREAT!

Jim Brady

Does it have a connection for the interface plug in the trunk?

LOVEMYBS

I don't know, I haven't seen it yet. I called the MB "parts guy" I've gotten to know and he said it would work in my BS. According to him it plugs into the cigarette lighter. He's shipping it to me. I'll answer your question when I receive it in a couple of days.

LOVEMYBS

It doesn't plug into the cigarette lighter but, it does connect to the separate connector in the left tail light area (see page 324 of your owners manual). The only thing I had to do was unsnap the female connector plug and then connect my charger to it. It works fine and I'm happy knowing I'll keep my battery charged for extended periods. The MB part number is B 6 7 54 2029. It costs $142.00 and I had it dropped shipped to my home.

alexander stemer

It's odd that my MB charger came with a cigarette lighter plug in, but today it totally discharged my battery. I'm wondering if you push it in all the way, could it partially activate the lighter component? I've never had a tender kill the battery, on any other car, but this one has done it twice. The first time it happened to me, I attributed it to the BMW charger. But, this was with the Benz charger supplied by my dealer. Riddle me that. AS

JonMBZ

If you read the owners manual of the trickle charger it states what vehicles can use the cigar lighter. IIRC its a ML and an SLR, but don't quote me on it.

LOVEMYBS

My tender came with a detachable cigarette lighter plug and a set of detachable jumper cables. I attached the cigarette lighter plug and tried to insert it into in my 12V plug, it doesn't fit. I then attached it to the interface harness in the rear as noted above and it worked fine. I then shut the trunk and used a bungee cord to keep the trunk lid closed. Works fine-