Battery Confusion

[Denis O]

I'm getting very confused over the battery set up on my new SL350, 55 plate, or to be more specific, the maintenance of the batteries.

I know it has a battery in the boot and 1 under the bonnet but which is the starter and which is the accessories? The dealer says that I should put the C-Tek on the boot battery but then the owners manual (USA) says the starter battery is under the bonnet so surely that's where the C-Tek should go. I'm guessing I should be charging the starter battery.

The car will often be left for periods up to 5 months so a C-Tek will be used but do I need to charge both batteries i.e. a C-Tek on each.

So which battery is where and which 1 needs to have the C-Tek attached when the car is not being used for a long period.

 

[alabbasi]

The front starts the car and will take much longer to drain down. The back one needs to stay on a charger if you don't drive the car much.

 

[PobodY]

Are they isolated from each other, or does charging one trickle charge the other?

 

[alabbasi]

Im pretty sure that they are isolated. Dont worry too much about the front one. I leave my SL55 parked for months and it will still fire up.