I am building a custom EV (three wheels; two front wheels, one rear) for driving on road. The rear wheel is the driven wheel. My specs are listed below:
Vehicle curb weight - 500 kgs (two seats)
Battery - 48 V Lead Acid 100 Ah (4 of these) - total weight 125 kgs
Motor - Golden Motor 3 KW Fan cooled
Motor Controller - comes with the motor
Drive - Using a CVT, final drive ratio of 10:1 which goes down to 6:1 based on speed.
I am trying to get the vehicle to have a max speed of at least 80 km/hr. However while testing I maxed out at around 35 km/hr. I have a feeling the motor is grossly under powered. The RPM maxes out at a range of 3000-3200 RPM, providing around 10-12 Nm of torque. I am using lead acid because it is way cheaper for the testing phase at least. I am planning to buy a 5 KW motor to maybe try it out, or should I go ahead and buy a 10 KW motor for the speeds that I want to reach.
I used a very basic equation to derive how much power I require and came up with 7.3 KW minimum. The equation I used was:
Power in Watts = ((Mass in kg) (9.8m/s²) (Velocity in m/s) (Rolling Resistance)) + ((0.6465) (Coefficient of Drag) (Area in m²) (Velocity^3))
Any help regarding this would be helpful.