What if I used a gear ratio that let it move the kart very slowly almost at human walking speed and it was a very light kart?
Gearing would either give you more torque or more speed. By running the motor at a high-speed and using gearing to drop the speed very low would create a high-torque situation. The high spinning motor would pull more power out of the batteries / solar.
I have a 12-volt powered
cooler made by
Koolatron. It has a fan on it with cooling fins to keep food cold for a long time when camping. It works very well as long as there is sufficient power to keep it going. My 13-watt solar-panel does not have sufficient power to run it directly. Running my solar-panel to a battery-pack (300cca) barely has enough power to run the cooler, and, the cooler will kill-off the battery about an hour.
My 80-watt panel puts out enough power at high-noon to run the cooler directly, barely enough power to run the cooler at sunrise / sunset. Just remember, the motor on the fan of the cooler barely pulls 4.5amp of power. The motor that would be required to move a scooter would probably pull in excess of 20amp. To have barely enough solar-power to run that kind of amperage would require 3 80-watt solar panels (each panel producing approx. 7.5amp) covering an area of approx. 24 square feet.
To make the most of possible electricity, use a single solar-panel to charge up deep-cycle batteries (12 batteries at 1-volt each or 2 batteries at 6-volt each or a single 12-volt "caterpillar" battery) and run the scooter for hours at a time on battery power.
In a few years, solar-systems might be at a point where a small 4x10" panel would be able to provide 40amp of power at high-noon - but - till that technology is widely available we must rely on stored power instead of direct power.