Hey, good idea, James,
There is an alternative. I can do this comparison analytically. I just put the parameters for each kind of car into the program.
Here are parameters you could consider--
Gasoline engine efficiency.......30% (to the shaft, good for a Prius)
EV efficiency, plug to shaft.....70%
My reasoning on this: charger, 95%; battery, 85%, controller, 95%, motor, 90%........... 0.95 x 0.85 x 0.95 x 0.90 = 0.69, close enough.
Feel free to correct me, either upward or downward.
I usually use 85% for transfer from the motor shaft to the wheels, and would use that for both cars unless you want to adjust it for the EV.
The cars may be about equal weight, or the EV with batteries could be slightly heavier, you can suggest values.
All other design parameters should be the same, like rolling resistance coefficient and drag coefficient. I don't correct for stop-and-go driving effects, making the results more appropriate for comparison of an EV against a hybrid with comparable regen capability.
Okay, if the numbers to be input are agreeable, then I can do a comparison calculation and report back. I will supply the program for others to try if you want.
Ernie Rogers
Quote:
Originally Posted by jamesqf
I think there is a fairly reasonable way to compare: start from the other end and do it experimentally. Find someone (or better, several someones) who've done EV conversion on say a Geo Metro. Find the same model that's unconverted, have them both drive a measured course keeping same speed &c, and for best results swap drivers in the middle.
Divide gallons used by KWh used, and there's your conversion factor. You can use that to work backwards through the supply chain to get total efficiency.
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