I've only got two at the moment, but thinking of having four in total if and when I upgrade to the Version 3 model. I sometimes drive a long way to shoot photo and video and occasionally run out of flying time. So a car charger and two more would be good. The other day my two batteries were drained and I came across a guy putting together a trike buggy thing. He then folded his huge kite to do kite buggying it would have made some great footage for him and me. The sad thing was I only had about ten minutes left flying and he didn't have enough wind.