At about 17mph I notice my Bionx conversion kit starts to throttle off with the assist. You can stay on top of the battery at this point that is, the battery isn't draining so much. The 20mph limit is more to define a bike as a motor vehicle requiring a license to operate. Bionx won't assist at speeds above 20mph, you are effectively in that neutral bike mode and pedaling on your own if you want to argue with the cops. Bionx is only looking out for their own legal arse, the governor can be thwarted if you search through all the discussions. But don't. Its a wonderful system as it is.