Benz-O-Rama

Mine does. The rear consumer battery has a piggy back module connected to it on one end and the other end is a 110v power cord. Apparently, you just plug and electrical cord into it, and the other end into your outlet and you're all set. It has 3 lights:

1. Charging
2. Nearing full charge
3. Fully charged

But my question is, is it safe to keep this thing plugged in 24/7? I started it today for the first time in a week and I got the "consumer electronics unavailable" message. Since I won't be driving it much in the near future, I wanted to make sure the battery doesn't die so on the off-chance that I drive it, it's fully charged.

Also, with the extension cord running to this module, the trunk needs to stay cracked. But that will leave the little trunk "dome" light on inside. That doesn't make much sense to me.

Anyone else have this module, and if so, how are you using yours exactly.

velvet fog

I'm pretty sure I don't have the module, but my car has sat for 3 weeks in the garage several times and I haven't gotten the "convenience functions temporarily unavailable" message. If you get this message after just a week, it sounds like your battery is nearing the end of it's life or you have something slowly draining your battery. Might be new battery time.

It's good to keep the battery charged. If you let it get run down and leave it in that state, the battery can become "sulphated" and will not be able to be recharged.

As far as the trunk light, I'm pretty sure I read in the owners manual that it will turn itself off after 15-30 minutes. Kinda wish the headlights would do the same.

Benz-O-Rama

Very possible that it could be time for replacement. Even though the car has no miles on it, it's still a 2005 and wasn't driven very often by the previous owners. A couple of guys in the SL55 section have this module, so I'm wondering if they were standard on the 55's and 600's. Good idea to just be able to plug your car into a normal outlet and keep it charged. I guess MB concluded that these cars would end up being a 2nd or 3rd car for most buyers, as in my case.

velvet fog

I saw in your other thread that the battery did not reach full charge even after being on the charger all night. How charged did it get? Unplug the charger and see how long it takes to run down.

When a battery gets fully discharged, it's really hard on the plates. Reaching full discharge a couple of times can completely toast an almost new battery. The number one symptom that this is the problem is that the battery will not take a charge.

If you decide the battery needs replacing, I'm sure you know to call roadside assistance. I'd like to see them come out in the snow to replace it in your garage. The manual also tells you how to DIY. Really simple and all you have to do is resync the windows and turn the steering to the stops on both sides.

Benz-O-Rama

Yeah, I plugged it in at midnight and left it on until about 9am. Most trickle charges are 8-12 hours, if memory serves. I'll plug it back in when I get home from work and let it charge overnight and see what happens.

I've let the car sit 3-4 days before without getting the warning. But this time, it's been about a week and bitter cold.

Racin_fool

I've worked on plenty of these cars and unless it was installed by the dealer pre-delivery, then it was installed at some point before you bought the car by a previous owner. All it is is just a small trickle-charger. Also, there is a nice trick to popping the rear hatch and making the light go off if you are concerned about it. Just open the rear trunk lid and manually flip the latch for the truck until it thinks its closed. The light should go off and all you have to do to pop it back open to close it is reach inside the trunk and hit the green blinking button to open it or use your key. That way no lights are left on and the battery gets a proper charge.

Benz-O-Rama

Great tip, thanks!

Actually though, I tried just leaving the trunk open to see what would happen. The light eventually went off, as well as the green flashing emergency open button.

But yeah, it was probably installed by the previous owner. It's branded as an OEM MB part, and piggy backs right on the side of the battery. It's pretty slick and is great for those weeks that I'm not driving it.

atebit

Is that the MB "3300" trickle charger you have?

Benz-O-Rama

No clue. Does the 3300 piggy back off of the rear battery or is it a stand alone charger that you connect to your battery?

My car is getting a full paint correction/detail done right now, so I won't have it back for a couple of days. I'll snap a pic of it when I get it back.

Benz-O-Rama

Here are the pics. I don't think it's the CTEK3300 that you're referring to, as that unit is a stand alone charger. As you can see, mine actually piggy backs right to the side of the battery.

atebit

Thanks for the pix...now I'm going to have to go out & look if my 05 SL600 has one. It looks like it has an MB decal on it, so it's gotta be something available from the parts counter...

ttdang123

I installed the CTEK 3300 (similar to the one you have but not from MB) and left it on when mine cars are in the garage.

All good.