# EV Calculations

5179 Views 8 Replies 4 Participants Last post by  mattW
Here are a couple of simple calculations that a person can use to estimate range.

range[km]=250 x capacity[kWh] / (mass[kg]^0.6)
-or-
range[miles]=250 x capacity[kWh] / (mass[lbs]^0.6)

Obviously these calculations do not take wind resistance, drive train efficiency, rolling resistance, etc, but comparing these results to results from sites like EvConvert.com may give a good idea of what range to expect from various EV configurations.

Here is another good site for graphs and formulas of this type.
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#### xrotaryguy

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Thot = Tcold + (K x ((Rhot - Rcold) / Rcold))

where K = 256.4 for copper
Thot = hot temperature in deg.C
Tcold = cold temperature in deg.C
Rhot = resistance at hot temperature in ohms
Rcold = resistance at cold temperature in ohms

#### xrotaryguy

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Hp=(torque*RPM)/5252

#### xrotaryguy

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Having a tachometer would be nice too. No sense in spending thousands of \$\$ on an EV conversion and not wiring up a tach.

#### xrotaryguy

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