--- me2 <

[email protected]> wrote:

>

> I'm trying to come up with a way to gage how many

> watt hours per mile an EV

> candidate will need.

>

> Has anyone done a coast down test to determine how

> much power or how many

> watt hours per mile a candidate will need ?

>

> Energy = 1/2 mass * velocity ^2.

>

> Take the car up to 70 MPH on a flat straight road.

> Put it in neutral. Time

> how long it will take to coast down from 70 to 60

> MPH. Calculate the

> energy at 70 MPH. Calculate the energy at 60 MPH.

> Take the difference.

> Divide by the time, should give you the power

> required to roll the car at

> the mean (or the geometric mean) speed. Yes/No ?

>

> Then to figure out the motor power, add in a factor

> for the differential and

> gearbox and the motor efficiency itself. Would

> this work ?

>

> I'm finding it hard to gage how much power a

> candidate will need at 65 MPH.

> I was using fuel consumption numbers, but they vary

> for the same vehicle

> depending which engine it has and what gearing it

> uses, so I don't think

> they would be that reliable.

>

> Comments ?

> --

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>

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> Sent from the Electric Vehicle Discussion List

> mailing list archive at Nabble.com.

>

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