My ninebot scooter (maybe not what you're asking, but it's a Segway product) slows down until it can't carry you anymore. First it just can no longer achieve th

My ninebot scooter (maybe not what you're asking, but it's a Segway product) slows down until it can't carry you anymore. First it just can no longer achieve the maximum velocity, then soon it can no longer reach standard speed, and then you're limping along at 4mph and you can no longer climb any grade without pushing. Finally you're pushing. It's not particularly usable as a scooter without the battery.