OK all... Yesterday while out for a few flights in the morning before the heat set in, all of a sudden my RC started beeping... OMG I forgot to charge it but thought I had enough juice left in it. So this cut short my morning flights. Then this occurred to me... What or when will I have to replace the rc battery and where can I get one as well as how do I install a new one. I have not seen anyone mention this subject at all.