I'm in my senior year of mechanical engineering. We have done several experiments with solar PV panels. The efficiency is 10-15% at best. That's a sunny day, no clouds, high noon, and the panel is directly pointed at the sun. That scooter may have (generously .5 m^2) solar panel area. At best your looking at about 15 W or .02 Horse Power. This will not be enough to replenish the battery fast enough. You need several hundred watts for a scooter, and for this thing to really have a 'limitless range' it would have to have 3 m^2 of solar panels. That's a 5.5 x 5.5 foot surface area. Far too large for a scooter. That's with the batteries.