I am new to R/C flying and have just purchased an aerohawk helicopter. The question I have for you guys is : What battery packs can I use for this, it is currently using a 7 cell 8.4V 700Ma battery pack. When I buy another battery pack do I have to use the same kind or can I buy one with a different amount of cells/voltage/Ma rating? If I can buy a different kind could you please suggest some to buy and possibly somewhere to get them online.

Thanks for all your help,
Dean

P.S. I am in the UK.