Choma

I've searched these posts for info on a trickle charger to combat my "electronic consumers offline" issue but I'm a moron and I don't understand what it plugs into on the car (front or rear battery? lighter?) and what it plugs into in my garage (AC?)

I found a photo of one online but the adaptor ends were cropped off of the pic. Can someone tell me how to use this and where to buy it? I drive the car mostly on weekends and it almost always gives me battery issues.

Possible I just need a new battery?

Scruffyone

Go to Sears and buy one, they are not a lot of money. Take the leads and screw them to the battery in the boot. There are screws on the posts/connectors. You can poke the pigtail up around the floorboard mat thingy. I plug the charger into AC and run the low voltage line into the trunk, and even close the lid too. When you want to drive just open up the boot and unplug. Make sure that you have some way of knowing it is plugged in. I walk into my garage and the charger is the first thing I see. If you enter your garage from the front of the car you need to put a note on the seat so you don't drive out with the charger attached.

Lincoln

You do need a new "rear" battery and then you should get a trickle charger to maintain that battery going forward if this is not your daily driver. Don't buy the Sears charger the other guy recommended...it's not a bad charger and I probably own the exact model he's talking about BUT the one I have is NOT a "smart" charger and you really want a "smart" charger (one that stops charging when the battery is fully charged). You want something like the Deltran Battery Tender Plus and you want to wire to the rear battery as lighter plug charging does not work in MBs. I have two Battery Tender Plus' and one Sears charger. I leave my SL500 and the SL65 hooked to the Battery Tender's continuously as they rarely are driven and save the Sear Charger for spot use (50A and 10A charging of dead batteries).

Leaving a "note" to remind you to disconnect is great advice. I typically just loop the extension cord thru the drivers door handle to remind myself to unplug the charger.

jmf003

I use a CTEK 3300 in my SL. Someone in another post suggested that CTEK manufactures the official MB chargers and they sure do look identical.

I have the 12v leads connected to the rear battery. I connect the 120v plug when I'm not going to use the car for more than a week or so.

It works well for me. YMMV, as the saying goes.

amgme

i use battery minder by vdcelectronics.com.

ajgk

My 06 SL55 sat for about seven weeks this summer. I was told by the parts manager at my dealer in Scottsdale to hook up the MB charger to the rear battery, which is the consumer battery. I did this. Everything worked after I got back except the starter battery. It was dead. I added water and charged it to no avail. In the dealers defense, they gave me a new battery under warranty. I took it home and everything is good.

I think a charger on both batteries may work. I don't know if this will cook anything.

Choma

Where do I get this smart charger? THANKS!

jmf003

For the CTEK 3300, just do a Google search and you'll quickly find a number of stores. For example, Crutchfields sells it for $69.99.

Likewise you can do a Google search on the brand name & model number for any other smart charger.

The official MB charger is almost certainly available at most MB dealerships.

HTH

Lincoln

The Deltran Battery Tender that I mentioned is available at many auto parts stores (like Pep Boys) or any BMW dealership (branded BMW). It's about $69 at the retail store or $46 online. I got the Deltran b/c that's what the shop that works on my SL recommended. I think any name brand smart charger rated at 2amps or less should be OK.

Auraraptor

Do you use maintainers on both the F and R batteries? Also, what about using a cigarette lighter-connecting maintainer? Would this keep both active or just the rear/consumer battery charged?

clint999

i use battery minder by vdcelectronics.com.

Scruffyone

The other guy?? WTF is with that???
I have a battery maintainer from Sears that stops charging when the battery is fully charged, which is not very long because of the drain of the "consumers".

mooneypilot

I read several posts about using the CTEK 3300 on the rear battery only. I've read on other forums that there should be two trickle chargers. Does the rear battery charger keep the front battery up as well?

DigitalKnight

I would like to know the answer to this also!! I have the Deltran Battery Tender from my 3000GT that I would like to use on my SL55 but not sure which battery to attach it two? Are they both linked together? Will it keep both charged?

55slamg

I use Deltran's "Battery Tender" Junior AUTOMATIC Model :021-0123, one on each battery. It comes with plug in leads that hard wire direct to your battery post for easy connecting and you don't have to worry about a clip disconnecting. They work great and only cost around $30 a piece.

DigitalKnight

That is the exact model I use. I have one on my 2006 Night Rod and was using one on my 1995 3000GT Spyder but want to move that over to the SL55....

So you are saying the batteries are not tide together? When the car is running does the alternater only charge one of the batteries?

55slamg

i would think the alternator would charge both batteries. I notice that my front battery goes green before my back one even with both chargers in place. Smaller battery size? Could also be a diode inline to prevent over charging from one battery to another from the charger? Maybe I don't need two chargers, good question DigitalKnight, will have to look into this more. I've only been an owner since august and still learning. These forums have some very knowledgable people on it, i'm sure someone can enlighten us.

DigitalKnight

I am sure you are right.... someone on this forum should know the answer.

-DK