+ 1 in the Varta is crap camp.
I'm with the others, I'd be buying a suitable charger.
I'd suggest one one of the Maha Powerex MH-C9000 chargers from Protog, I have one and they're fantastic.
They charge, analyse/refresh, break in, discharge , have variable charge rates on each or the 4 slots, will work on 12V as well as having a variable voltage source plugpack plus a 3 year warranty (they don't come with free steak knives).
http://www.protog.com.au/buy/maha-po...-analyzer/9000