The battery charger that Kans shows charges one battery at a time, once the battery is full it will automaticaly power the next one. The battery take's care of ballancing and max charge, it will protect it's self. This will take more time but you won't have to go and plug your other batteries after one is finished. For the price and conveniance of being able to just leave them and go makes this for me a good deal.
<$20, how can you go wrong... I ordered one also from the same vendor. I got an email 30 minutes later say it had shipped, hopefully soon I'll know first hand if it works well or not...fingers crossed!