I would if it was me...find a friend with a big battery and try it. I suspect you are exceeding the continuous flow rate. If your controller will allow 25A but your continuous flow rating on your battery is 20A you will bonk (tap out) when your BMS says enough. The battery will re balance in short order but will continue to tap out again and again , sooner and sooner, as it reads battery temp. Your individual cells might also have pcb limiters that prevent over discharge. All individual cells have a max discharge rate ranging from 8A-35A. Exceeding this will cause a shutdown of a string. A 13AH batt will have 5 strings a 20AH will have 7 assuming you have a 48-52v system. You may not have every string shut down at the same time and hit a half power feeling. This happened to me frequently when I had a smaller battery and I wanted to put the hammer down. If you know somebody who can wire the right leads on so you can try a bigger battery ...your in business , provided you don't exceed the max the controller can handle. My son the scientist and computer engineer played with his controller and allowed a higher flow rate than his controller could handle and burned up a controller. $50 and a week later the bike was running like a clock with a new controller.
