The newer NiMh batteries such as the Eneloop hold a charge about as well as LiPo's do and are a much better battery for transmitter use than LiPo as the hold a charge as well as LiPo's do and can be charged in place with the old wall wart or your current NiCad/ NiMh charger. Just read the data for your battery and make sure you get an LSD (low self discharge) type, several companies other than Eneloop now make them.