The gravity of a 300 kg car is 3000 N and the coefficient of friction is 0.5 (the real situation is even higher, 0.9, it may depend on which direction you are going )
The tensile force of 1500 N is driven by the motor and the torque is transferred via the gearbox. To enlarge, you need to calculate the transmission ratio of your gear. Assuming it is 1:100, then your motor will produce 15N of torque. You know the output torque (output.torque) of the motor. Depending on this, choose the motor marked on the nameplate. Power outputs based on voltage and current. Assuming it is 48V 20A, the effective output power of your solar panel is 48 × 20 = 960W. This is simply driving at a constant speed on flat terrain, so it is estimated that you need at least 1200W of effective power output. The combination of a battery et of a solar panel is more economical.
Solar panel<. /p>
Motor
Wire
Four-wheel drive vehicle as the main body
Buy a solar panel and add it to a vehicle ready to toy car employment. It is recommended to use a four-wheel drive vehicle as the main body and connect the panel wires to the two poles of the original battery box. Note that the power of the battery panel must meet the needs of the engine.