You also want a charger that will balance the pack. An 11.1 volt LiPo actually contains 3 separate cells. Over time, the cells can become unbalanced, and do not charge uniformly. A balancing charger (Look at the FMA Cell Pro 4s charger) charges each cell individually. The final charge should be 4.2 volts/cell. A quality LiPo battery should have a separate charging adapter that allows individual cell charging.

Brad