The Great Electric Motorcycle Range Con
How how far can an electric motorcycle actually go? That depends on how the bike is tested and how much work you're asking the battery to do.
We all know the game. Big range number on the brochure, smaller number once you hand over your hard-earned cash and start riding the thing.
The reason it keeps happening comes down to how electric two-wheelers are tested, and the maths gets pretty crazy once you leave the gentle, controlled world of the test cycle. Let’s break it down and try to make sense of why we’re all left disappointed once we get on the bike.
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The Electric Motorcycle Range Game
In India, electric two-wheelers are tested using the Indian Driving Cycle, or IDC. The test measures energy consumption in Wh/km, with the 2-wheeler test cycle averaging roughly 22 km/h (13.6 mph).
Europe does it differently. If your bike is type-approved in the EU, it'll be tested using the World-harmonised Motorcycle Test Cycle, or WMTC. It's a different test cycle, with its own mix of speeds, acceleration, deceleration and riding conditions.
The US has its own system too. Electric motorcycles go through the EPA certification process, although the range testing is different to the city-and-highway system used for electric cars.
So, three major markets, three different ways of working out how much juice an electric motorcycle uses. Now let's see what those numbers actually mean when you stop testing and start riding.
The Range Reality Check: When Air Fights Back
For simplicity, we'll take the IDC's 22 km/h (13.6 mph) as a starting point. A bike with a 3 kWh battery can potentially claim around 150 km (93 miles) of range under the IDC. It's achievable within those test conditions.
The thing is, at 22 km/h air resistance is relatively low, so less of the battery's energy is being spent fighting the air.
Now wind the speed up to 50 km/h (31 mph). That's hardly hooligan territory. It's a normal road speed in most European cities and right in the mix for US urban arterials. At that point, things change quickly. Aerodynamic drag rises with the square of speed. Put simply, twice the speed means roughly four times the drag. So the faster you go, the harder the air starts kicking back.
Take a 170 kg (375 lb) bike-and-rider combination and run the numbers at 50 km/h (31 mph). Our back-of-the-envelope calculation gives roughly 25 N of rolling resistance and around 70 N of aerodynamic drag. That's about 95 N pushing against the bike as you ride.
At the wheel, that works out at roughly 26 Wh per kilometre. Once you allow for drivetrain losses and the bike's other electrical systems, you could be looking at around 40 Wh/km.
Now run that same maths with a 3 kWh battery and you're in the region of 75 km (46 miles) of range at that sort of speed. That's a long way from 150 km. In fact, we've just cut the IDC range figure in half. And we haven't even mentioned hills yet.
But before anyone starts shouting that we've discovered the one true range equation, sorry, we haven't. It's just an example. Put a lighter rider on the bike, fit better tyres, ride slower, add regenerative braking or ride a bike with decent aerodynamics and the number changes. Add weight, hills, cold weather, headwind or a heavier right hand and it'll go the other way.
The battery hasn't suddenly got worse. You're just asking it to do more work.
Can Regenerative Braking Save the Day?
Regenerative braking puts some juice back in the battery. But unfortunately, it's not a magic range button.
At 50 km/h, our 170 kg bike-and-rider combination has about 4.55 Wh of kinetic energy stored in its forward motion. A recent electric motorcycle study measured maximum overall regenerative recovery of 22.5%, which would give us roughly 1 Wh back into the battery from a full 50 km/h stop.
1 Wh... Against our estimated 40 Wh/km consumption, that's about 2.6%. And that's with us stopping from 50 km/h to zero every kilometre. In the real world, you won't be doing that.
So yes, regen helps, especially when you're hammering through stop-start traffic, but it isn't going to turn a 75 km bike into a 150 km bike. And here's the bit people often miss: you can't regenerate energy you've already lost fighting the air. Regen only gets a shot at energy still in the bike when you slow down or descend.
The BCB Take
We're not bothered by a manufacturer publishing a certified range figure. If that's the test the bike has to pass, crack on.
What bothers us is when that number gets slapped on a brochure like it's gospel, like that's the distance you're going to ride before the battery light comes on. It isn't.
If you're buying an electric motorcycle, Wh/km (mile) is arguably more useful than a giant range number. And we're seeing it more regularly from some manufacturers. Give us the consumption figures at 50 km/h (31 mph), 70 km/h (43 mph), 120 km/h (74.5 mph) and we have a much better starting point for judging what the bike might do in the real world. We'd still have to factor in rider weight, weather, throttle use and road inclines, but we'd be getting there at least.
Until manufacturers find a better way to give us that data, or make the tests more representative of how riders actually use their bikes, we're stuck doing the maths ourselves.
And that's fine. We're bikers. We can handle a calculator.
Ride safe, folks.
Want to see the range numbers for yourself? We’ve pulled together the most detailed range data we can get from the OEMs in BCB Bike Compare.
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