New to the Benz world as of late summer last year. Bought a 2003 SL500 and stored it for the winter. Was advised to put charger on front battery. Did so and yesterday after checking on the car, noticed that the rear battery was drained. Can you put a charger on both the front and back batteries, and at this point should I put it on the back, or just take it somewhere when I take it out of storage? Thanks in advance.