It is just a test to see this motor's ability, it drives 2 adults easily. as the skateboard is not stable, it's hard to stand 2 people... For more information, please feel free to contact us: service@l-faster.com
For a 48V battery, I recommend using a 48V controller, but using the 36V motor is overvoltage, yes this will give it more power, but maybe reduce its lifetime, not good for the motor.