I was wondering what some of you may consider as being a suitable battery for very high power density applications? I know A123 is an obvious choice, but I was looking at something a little more economical and still decently powerful. Right now I have a pocket bike that i've converted to electric, usual swing arm extensions and what not and using 320 1/2 Saft nicad cells. These work decently well, but they seem to not be as powerful as I thought.
My setup is using a 48 volt 700 amp logisystems controller, and i would like to try and take the full benefit of it but as economically priced as possible as far as the batteries are concerned. I've considered the sub c nimh cells in RC hobby shops and such, but what other options should i look into?