Power requirements for electric vehicle
Power requirements for electric vehicle
(OP)
I want to verify that a vendor is giving me the correct sized electric motor for a vehicle (hp, amp, voltage, etc.) How can I do this?
The car must travel 8kph; carry 1000kg load (exclude driver). Top speed can be reached in 5-10secs. It runs on 4 vulcanised wheels (like golf carts). The entire length of runway is only 1.2km with slope 1:6 at the beginning and levels off then 1:6 incline at the end.
The car must travel 8kph; carry 1000kg load (exclude driver). Top speed can be reached in 5-10secs. It runs on 4 vulcanised wheels (like golf carts). The entire length of runway is only 1.2km with slope 1:6 at the beginning and levels off then 1:6 incline at the end.





RE: Power requirements for electric vehicle
8kmph corresponds to 2.22m/s. If the car weight is 1000kgs then the mass is 1000/9.81 kgs and the force for accelerating the car from 0 to 8kmph in 5 sec. will be 1000*2.22/5 = 444N (1000/9.81kgsx9.81N/kg)
If the car runs at 2.22m/s then power is 444*2.22 = 985.68W(1.34hp)
The low value is because we are neglecting wind resistance and friction.
Ideally, you should conduct a deceleration test by first running the car at some constant speed and then coming to neutral. Note the time 't'in which the car speed reduces from x to y m/s. x-y/t gives you the deceleration and using the above method you can get the hp required.
Regards,
RE: Power requirements for electric vehicle
For a normal Electric Vehicle I found on Web 'typical' hp is much higher than this, ~20hp.
Anyway, now I have Hp, how then do I select the correct DC motor? or how do I know what the supplier has offered is the right equipment? (Voltage, amp, torque, rpm, etc.)
RE: Power requirements for electric vehicle
That is a factor of safety when you have to drive against heavey winds and uphill etc.
Electrical engineering is not my cup of tea(or atleast it won't have the required ingredients). The experts here will help you out.
PS: Why can't you ask the manufacturer for a design qualification?
Regards,
RE: Power requirements for electric vehicle
RE: Power requirements for electric vehicle
Other things to consider:
Wheel bearing drag.
Steerage peak drag. (Tire scuffing.)
Windage.
Motor Efficency.
Gear box losses.
Differential losses.
Motor controller losses.
Maximum slope.