# Formula for power need for an EV



## kerosene (Mar 21, 2010)

here is attached screen grab

you can input speed, weight, road grade (incline), cross section area, drag coefficient and rolling resistance coefficient. 

inputs are in metrics (m/s, kg etc. but lbs, mph etc. are shown)

The drag coefficient is going to be a guess - but by comparing to other shapes one can get a rough idea. 

The given watts/hp are net - so any efficiency losses would have to be counted for - and obviously this works just as a rough guideline. 

Lemme know if you fins errors or have suggestions or other comments.

I think these are my 1st posts too so,

Hello everyone!


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## Franky.EV (Feb 27, 2010)

Also check this :

http://www.diyelectriccar.com/forums/showthread.php/yes-another-ev-calculator-45278.html

It takes care of lot of parameters, including gear ratios, motor torque curve, etc.


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