I would like to say something about the previous posts regarding the spare battery 1800mAh, 3.7V). I for several years working in the flight model sport with Li-battery Li-Ion / Li-Poly). Therefore, I can confirm by my profession that the batteries need about 15 charge cycles until they reach full capacity. It is also important that if sieüber a long time to be stored have a capacity of 60% them.The batteries should only be charged to 100% when they are placed in the next 24 hours in use. So much for the theory so far I could not continue this battery test but I'll still be another feedback.