Startability and Gradeability of Electric Vehicles

• If the desired rate of change of potential energy exceeds the maximum power output, it will slow and may stall on the slope.
• If the slope exceeds the coefficient of friction between the wheel and the surface, it will slide on the slope.
• Axles that are not driven subtract from the vehicle's ability to climb any given slope.

Google "Swiss mountain railways" for more information about electric vehicles on slopes.

You can estimate power output by multiplying motor current and motor voltage.

You need to get a speed vs torque plot for the motor (for dc motors, the maximum torque is usually at stall). Using the gear ratio from the motor to the driving axle, you can get a plot of speed vs torque curve for the driving axle, and using the radius of the driving wheel you can convert this plot to speed vs driving force. (This could be determined experimentally using a dynamometer.)

The amount of force needed to start climbing a hill is the weight of the vehicle times the sine of the slope angle. If the zero speed force exceeds this, the vehicle can start on a hill and accelerate. (You could determine the zero speed force using a force gauge secured to the vehicle and a stationary support.)

Travelling at speed, the driving force needs to overcome the restraining force of gravity (wt x sine slope angle) and wind drag (which is proportional to the frontal area and the square of the speed and may or may not be negligible). The speed at which the driving force equals this restraining force is the maximum speed.

So if you make a plot of speed versus driving force and overlay a plot of speed versus drag force for various slope angles, the speed where the curves cross (same force) is the maximum climbing speed.

Contact the SAE. They will help students who need tutoring.

Have brothered to do any searching for the data.

Do you have any thoughts on the subject or just a void?

Where have you looked so far?

Have you asked your instructor?

I'm not a student.

Search for"jumpjack"and "electric" and "Cd calculation" and "60 mph"before wasting time replying.

Then use your saved time to have a look to jumpjack.wordpress.com

I was just looking for confirmation by specialist of transport about my research and calculation.

I also need some literature data.

What have you got against being a student. You do not have to be enrolled in a formal school with a curriculum to be a student. Let the world and life itself be your classroom. I hope that I learn something new on my last day on Earth. I will always be a student.

As for your original question, I'm certain one cannot easily calculate the top speed any vehicle can climb a grade or accelerate from a start. If one could easily calculate this I doubt there would be real hill climbing races or drag races.

You gave no explanation, showed no calculations, said notbing about research gave no hints that you were a whatever you are instead of a lazy student.

I'll pass on the website.

Good luck.

There are other issues at work also. An electric golf cart may be fine for running around for many hours on flat ground. But that same golf cart will loose way too much battery life if we need to climb the ramps of the parking garage. For that reason, we had to dismiss an electric golf cart for use in the parking garage.

In your case, gradeability is not a constant. What it can do after a full charge, and what it can do after two hours of work may be different. Your battery pack will have to store sufficient energy for the full work shift. I hope this helps.