Lets try the blindingly obvious first FLAT batteries?
Next.......
How have you connected the 7.2v batteries.... in parallel or series?

I.E.
Positive of both 7.2v batteries connected together and both negative.... then connected to your controller. PARALLEL

Or positive of one 7.2v battery connected to the negative of the other 7.2v battery........the remaining 2 leads ( a positive and a negative ) connected to your controller. SERIES
PARALLEL gives you 7.2v.

Tsk ......Beaten to it...
Seems my post is superflous....:sad:
SERIES is the correct way to get 14.4v.

(Message edited by woody on March 16, 2006)