Hi folks, Today I took delivery of a bafang bbs02 and a 48v battery. I thought I would try it out before fitting to my bike. I charged the battery and plugged it in to the motor connected the c965 display and the throttle. I turned the battery on and then the display. pressed the throttle and it started to turn then I went up a few pedal assist levels and tried again the motor turns but the display shows the battery and motor symbols flashing blank. It's also displaying an error code H21. Can anyone suggest a fix before I start fitting the kit to my bike. Thanks in advance. Phil