SL(r230) aux battery charging?

[mat8n]

My 03 SL 350(R230) will be parked up for 2-3weeks i a carpark while i'm away at work. I'm after fitting a solar charger to it.
Does the cigarette lighter socket charge the aux battery?(i know you have to make the fuse permanent live)
Or how else would i get the battery connected through to the interior of the car?
and what wattage should i get? is 4w enough?

Thanks
Matt

 

[whitenemesis]

The front mounted battery is only connected to the starter armature and so should not suffer any drain whilst parked up.

 

[mat8n]

Its the auxiliary battery in the boot i want to keep trickle charged.
What i'd like to know is, if i plug a solar charger into the cigarette lighter socket, will it charge(keep topped up) the battery in the boot?
Thanks.

 

[whitenemesis]

The one in the boot is the Systems battery. If the cigarette lighter socket is live with the IGN off it will pass charge to the battery. Whether it would be sufficient to maintain the battery is another matter. I don't know.