alan s 

Sure. Did you factor in weight, wind resistance, terrain/environmental factors, temperature, etc? Seems vastly oversimplified.

Robert C

Of course it is simplified, as is any general heuristic. To arrive at an accurate number, for any given bike and rider, there would need to be a datalogging wattmeter positioned on the bicycle. Such wattmeters do exist and the results are regularly shared in conversations such as this one.

All that being said, while more complicated tools, like this range calculator, do take more factors into consideration, 20Wh is a good rough estimate for an e-bike of normal bicycle configuration operated at normal bicycle speeds. If you were to replace the 20 with some other realistic number, you would still reach the same conclusion of:

alan s 

What is normal? 300 pounds rider and bike combined? Seems typical for around here. 28 mph? Many around here ride at that speed.

RubeRad

OK, well the bike I linked doesn't state the KWh of the battery, it just says "Impulse Evo Li-Ion 36V". And for Engine, "Impulse Evo RS, 36V / 250W, with shift sensor Technology". And hovering over the "205km" icon it says "This Kalkhoff pedelec can cover a distance of up to 205km when using lowassist levels in ideal conditions with a fully-charged battery".

I assume the statement is true. (When have the Germans ever lied about energy consumption?)

ItsJustMe

Given that on at least the kit I've been looking at, "assistance" is highly variable, I doubt that one formula could convert watt hours into an assist distance.

RubeRad

I assume their max 205km claim is assuming level ground, no wind, minimal assist setting, and a certain, constant number of watts from the cyclist. Note, they're not claiming a 'typical' distance, they're giving an upper bound, a theoretical maximum, given "ideal conditions". Easier to estimate than "typical", because everybody's typical is different.

350htrr

When you go deeper into their site you find out it's a 36v 17Ah battery, that works out to 612 watts.

It's an average, agreed to number, you can also use 25 if you want some reserve power, and over time achieved by many users, seems to stand up and work out... It's like the MPG "measurement", some people get better than others some people get less, but it's a base to start from...

350htrr

Yes, most manufacturer's Numbers are a bit optimistic in the real world... Although my BionX manual say's 106KM on level1 assist per charge and I can pretty well always achieve it.

InTheRain

I have a 350 watt bionx motor. I find that riding my carbon fiber bike is easier than riding my bionx powered ebike on level1 assist. It's just due to the weight. Level2 assist is about equal to riding the carbon fiber road bike. I notice a big difference at level3 and level4 assist. However, the mileage range goes down significantly with each level of assist. I've never completely depleted that battery, however, switching between level 3 and level 4 on longer rides, I find that my battery is at about 10-15 percent at 30ish miles. Of course, I'm not a 160 lbs rider... 230 lbs here.

So, riding level 1-2, I might get 50 miles... but it would be more of a workout than riding my carbon fiber road bike for that same distance.

350htrr

Yes, I believe an assist is just that... A "Little bit of help going up hills or going into the wind". Once you start to use it as a way to keep your speed up or not pedal as hard up the hills or into the wind, it WILL take more power, thus reducing your range, which I believe more people riding E-Bikes do, than not do. Basic fact seems to be, that 20 to 25 watts per mile is what most people use when riding an E-Assist bike, thus about 30% of the total ride is done by the motor and the rest is done by the person pedaling... (on average)... Now, there are some people who only get 50KM per charge on the same system that I use and I get 100Km, what does that mean...? Easy, they are pedaling 50% less then I am...