The easiest way is to just get a better charger. The Hobbico 900 is great for cars, but if you get into park flyers, it'll be a "park fryer," as in fried batteries.

While it's DC only, you can get a Hitec CG340 for less than $40 that will charge up to 16 cells, and has adjustable current with peak detection. You'll like flying so much that most of your charging will be done at, or on the way to, the field, so who cares if it's DC only, right ? Old PC power supplies can be converted into 12V bench power supplies quite easily.