R230 SL batteries

[chris hitchen]

Hi all
The sl is put away for the winter now but I have one question about the two batteries.
I have bought a ctek conditioning charger is it ok to connect this and charge the batteries whilst they are still connected to the car
Thanks in advance

chris

 

[SLacKer]

I have charged the rear battery whilst connected to the car without an issue.

The front battery only gets used for starting the car so should last a long time, there are warnings in the manual about charging it so I would disconnect the front battery.

 

[NW_Merc]

I didnt know MBs had two batteries, I learned something new today

 

[BTB 500]

I didnt know MBs had two batteries

Only some models.

 

[NW_Merc]

Only some models.

Do the SLs have them specifically? Is it to do with the folding roof drawing more power?

 

[richard]

SL, and early W211 E classes - I think the W221/W216 may do also.

I think its due to the fact there are so many control units it the car drawing a few milliamps when the car is off that if you leave for a few weeks there wouldn't be enough left in the battery to start the car (and thus the starter battery is used to start the car, and then the consumer battery is charged).

I think they stopped on the W211 but kept on the SL, and I have always assumed that this is because it was an expensive feature (2nd battery and battery control module etc probably added €50 to the car) and E classes in general get used a lot more regularly that SL which tend to go weeks without use. There was quite a lot of trouble with the battery control module software in early E classes.

Seems to work well in my SL which gets occasional use when its not the summer - always starts although often in the winter I get the message that the consumers are switched off until the consumer battery charges up (after about 1-2 weeks of non-use)

R

 

[DSLiverpool]

Guys can I charge the rear battery from the REAR boot mounted cig lighter /power socket its on the right of the boot near the back light, I would prefer that to a clipped on battery - I dont want to connect it until i know