So I bought my CX2 used and it came with cheap batteries for the Spectrum TX that read 5.6 volts. After more then 200 flights I am down to 5.0 and just started to go to 4.9 volts. It seems these batteries last forever! I will replace them once they read 4.9 volts consistantly. Do yours last forever? My old Tx for my RC truck uses 8, has less range and the batteries are only good for about 30 runs.