http://www.radioshack.com/product/in...lterValue=DPDT

Picked one of these up today, and ordered some balance extension plugs off ebay, one of which will get sacrificed to making my little rig to allow my charger to charge a single cell through the battery's balance plug. I guess something like this or this would be more generic if I needed to handle > 2s packs, but I don't, so a dpdt should work just fine.