### What is your watthours per mile?

Posted:

**Aug 06 2013 6:00pm**I'm trying to figure out whether my bike is as efficient like I'm expecting, so I'm doing testing. I'm wondering if my squeaking wheel is affecting efficiency and whether that warrants servicing it?

I was doing some testing on my bike recently, it's a Bike-E recumbent like this.

Normal riding position

Voltage: 24v

avg-speed: 13.5 mph

Rear tire: 40psi Knobby

Wh/mi: 15.5

Normal riding position

Voltage: 48v

avg speed: 12.5 mph

Rear tire: 100psi comet primo low rolling resistance tire

Wh/mi: 11.7 wh/mi

Draw legs close to the body, bring in head. (Curl up into a ball) [To minimize frontal area]

Voltage: 48v

avg speed: 12.5 mph

Rear tire: 100psi comet primo low rolling resistance tire

Wh/mi: 10.5 wh/mi

One time, I was trying to maximize my range because I had no idea how far my bike could go and my derailleur was busted so I couldn't pedal, so I went 10 mph and coasted wherever possible and minimized braking (To conserve energy).

Normal riding position

Voltage: 48v

avg speed: 10 mph

Rear tire: 100psi comet primo low rolling resistance tire

Wh/mi: 9.2 wh/mi

A neat way to figure out your watthours per mile, without relying on a CA to do it for you, is by dividing your power output by your speed.

So, this one time I was going 26 mph and my motor was consuming 450 watts, so my wh/mi at 26 mph was (450/26)=17.3 wh/mi. (I had my 40psi knobbies on at the time)

On my older upright bike like this:

It was consuming 770 watts to sustain 25.5 mph, so my wh/mi. was (770/25.5) = 30wh/mi which is a figure I remembered seeing on my CA.

I was doing some testing on my bike recently, it's a Bike-E recumbent like this.

**UNASSISTED:**Normal riding position

Voltage: 24v

avg-speed: 13.5 mph

Rear tire: 40psi Knobby

Wh/mi: 15.5

Normal riding position

Voltage: 48v

avg speed: 12.5 mph

Rear tire: 100psi comet primo low rolling resistance tire

Wh/mi: 11.7 wh/mi

Draw legs close to the body, bring in head. (Curl up into a ball) [To minimize frontal area]

Voltage: 48v

avg speed: 12.5 mph

Rear tire: 100psi comet primo low rolling resistance tire

Wh/mi: 10.5 wh/mi

One time, I was trying to maximize my range because I had no idea how far my bike could go and my derailleur was busted so I couldn't pedal, so I went 10 mph and coasted wherever possible and minimized braking (To conserve energy).

Normal riding position

Voltage: 48v

avg speed: 10 mph

Rear tire: 100psi comet primo low rolling resistance tire

Wh/mi: 9.2 wh/mi

A neat way to figure out your watthours per mile, without relying on a CA to do it for you, is by dividing your power output by your speed.

So, this one time I was going 26 mph and my motor was consuming 450 watts, so my wh/mi at 26 mph was (450/26)=17.3 wh/mi. (I had my 40psi knobbies on at the time)

On my older upright bike like this:

It was consuming 770 watts to sustain 25.5 mph, so my wh/mi. was (770/25.5) = 30wh/mi which is a figure I remembered seeing on my CA.