I built this for my girlfriend, now my wife back in 2013. It is a three wheeler with a 600 W hub motor. What's happening now is that even with a full charge on the 36 V battery pack. The three light gage on the throttle will read full charge but when she applies power she says she hears a crackling noise in the controller area and the three light gage reads low battery. I am thinking controller, she has beat the throttle up pretty bad but it seems to be working. What do you think is the problem?