I've been thinking about getting a battery maintainer for the SL since I only drive it one day a week and I know the SL has lots of electronics and pumps running all the time...

I currently have a Battery Tender Plus for another car, but when going to buy another one it looks like there are a few concerns from the newer units failing. I'm also not a fan of constantly having this little "box" sitting on my floor that I feel like I'm going to step on all the time. I did hook up my BTP for a day to the SL, and it stayed red the whole time - it never went to float mode and the unit stayed hot. So I'm assuming something wasn't liking each other, or the drain on the battery is higher than the tender can provide. Not sure.

CTEK 3300 seems to be the MB OEM option and has good reviews. The BatteryMINDer 1500/1510 doesn't seem to show up too often here on MB's, but does seem to have good reviews.

Any of you guys running either of these units?

 

while it's not the model your looking at, i'm using the CTEK Multi US 7002. been very happy with it, keeps my battery charged when i'm away (sometimes months at a time), reverse polarity protection (i accidentally reversed the connection, the CTEK let me know there was a "Fault") and the power & connection cords are long.

 

Have several maintainers for other cars, but a CTek for the SL55. The Absorptive Glass Mat batteries seem to be particularly sensitive to maintainers - and the CTek does a good job on my nearly new battery.

 

I ended up buying the CTEK 3300 unit since it was the OEM MB supplier. How do you guys leave yours connected? Just feed the wire over the trunk seal and crunch it? Constant pinching of the wire may not be a good thing?

 

this is how i ran the wire out. i tuck it behind the tail light. no issues thus far.