SUGGESTION: Additions to aerodynamic, rolling resistance, fuel economy calculator.

[sheepdog 44]

It would be really helpful if a new column could be added that gives you wh/mi in addition to mpg. For example, you take a look at the 55mph column, it says you consume 7352.5 watts at 55mph. 7352.5 / 55 = 133wh/mi. It's a simple thing to do and saves time mentally calculating.

Please, wh/mi is really useful information!


My second request would require a little more effort. Please add a gradient function to the Aerodynamic and rolling resistance calculator. The calculator is incomplete because it's always telling you your on a level road, and most of the time your not! Knowing the power, and therefore fuel economy (completely ignoring BSFC of course) required to climb a grade is useful when designing an EV. It gives you an indication of how much power you need for your motor, and the wh/mi you'll get to size your battery pack accordingly.

(We have this part) ...........(missing this part)
.I..........................................I..... ....
V..........................................V...... .
P = (krMs) + (kaAsv2d) + (giMs)

where

P = power required (in watts)
kr= rolling resistance coefficient
M = mass of bike + rider
s = speed of the bike on the road
ka= wind resistance coefficient
A = the frontal area of the bike and rider
v = speed of the bike through the air (i.e. bike speed + headwind or – tailwind)
d = air density
g = gravitational constant
i = gradient (an approximation²)

[sheepdog 44]

Another thing to add which is semi useful. You can figure out the exact negative grade that will maintain the constant speed of your vehicle while coasting. This would be the ideal negative grade to look for in a route so you could EOC in Neutral without gaining excessive speed, or slowly loosing speed.

i = ((krMs) + (kaAsv2d)) / (gMs)

Please add two columns for this. One that neglects transmission efficiency for EOC in Neutral. The other that accounts for transmission efficiency. The second would only be indicative without knowing what your engine pumping losses are.

It would be a great feature to have and would save me and hopefully others a lot of time using the calculator in google!