Unless you have a strange balance adapter board, the board should have a 3 pin connection for a 2S. They are all made this way, I have one of each type adapter board sold by Hyperions and they all have a 3 pin socket on the board for connectiong a 2S lipo balance plug. Maybe you have something different?

If this is your lipo -

http://www.rcmart.com/catalog/rc-bat...e-p-30503.html


That appears to be a JST-XH plug on the linked lipo and you'd need this -

http://www.allerc.com/product_info.p...oducts_id=3159