G'day Mate
I use an ACE Smart charger I'm sure you can get em easily in the USA, they are a reflex charger that will charge both TX & RX at the same time, & eliminate memory problems & restore older batteries if use with a cycler. I also use an ACE cycler which is a good way of determining your battery capacity. It shows exactly how much capacity your battery has in Milliamps, so you simply charge then discharge & you should have an increase in capacity after a few charge discharge cycles.
Good Flyin Mate
Allan