I see a lot of talk about RX batteries and how many flights you can get with them. If you have to buy a new battery why not get something like a sanyo 2500. For about 20 bucks. I normally use 6v and I am running sanyo 2700. Not that I want to fly all day, but at least I can fly 3-4-5 times then recharge. maybe my thinking is all wrong. I guess if you are going to run the battery close to marginal doesn't make any difference if it iis 600 or 2600. Just my 2c.