Hi I am new to the E bike world but think I am some what capable of working on things. I have had an A2B given to me because it doesnt work. The battery is testing out good at 35v. I put the battery back in and the bike turned on and worked, I rode about a mile and while having the throttle wide open it lost power. I flicked the key back and forth a couple of times and it came back on, rode for a while longer and the same thing happened again. Key ingintion checked out with a multimeter, so I was thinking its the external controller (mounted below the battery). I can't seam to find the exact replacement part online. If anybody has any other advice on what they think it might be or where I can find a controller it would be greatly appreciated.