I tell you guys I have a ultra stick 25e also and at first I was concerned about the cost of batteries. Then I found out about perfect balance from skysharkrc.com I am currently using the 3s1p4000 10c and it is doing great. I have the 25 with a 12 x 6e apc 60amp speed. I also have been looking at the diamante , I first bought the 32 for my stick then found better performance with the 25 on a three cell. Therefore I also believe it would need the four cell with the 32 like they call for. Hope this info will help you out. They have now come out with some 15c batteries that would work in the pulsext. Happy flying