One thing that the Control-board does is send information to os x on how much juice there is left in the cells. I failed to "calibrate" (load it full,unplug, wait untill it goes to sleep,fully recharge) So mine does think I have more power in the cells then I actually do.
This might be a problem to you though, with the control board thinking that it has less juice then it does.
If you find a way to reset the control-board memory I'd be happy to know!