Electric Bicycle Battery Range Explained
October 8, 2021
One of the facts prominently stated by the manufacturer about almost every ebike is the range that the ebike is capable of, that is to say: the distance that particular ebike can travel on a single charge.
If you’ve ever delved into the specifications of multiple ebikes, be it looking to purchase one or just through pure curiosity, you will have found that electric bike range can vary greatly amongst ebikes that have very similar technical specifications. This might have left you quite puzzled and thinking to yourself: am I missing something important?
You should rest assured that you are not the only one thinking this. The first truth is that there is no industry standard for calculating electric bicycle range, and one must delve into the fine print provided by each manufacturer to uncover how they get to the e-bike range number they state on the poster. Some run multiple tests and use an average, some run the math and find the average that way, and others put down the highest number they can pull from either of these processes; after all, part of this is marketing.
If you’ve taken the leap and bought yourself an ebike -congratulations!- you might have found that you’re not getting the manufacturer's stated range out of it for yourself. Or you might find that you’re surpassing it. You will undoubtedly have realized over multiple adventures on your ebike that the range will fluctuate. You and your partner or a friend may have the same ebike and ride together at the same pace but one of you runs out of juice faster than the other. So what gives?
The truth is that multiple factors affect an ebikes range, some of them are mechanical, some of them are electrical, and many of them are external factors. Here we’ll delve into each of these as we get to grips with the ebike range.
The external factors affecting an ebike’s range are plentiful and some of them can be altered to improve how far an electric bike can travel on a single charge; more on that later. These external factors are:
The heavier an object is the more force it takes to move it. Thus, the heavier the load on the ebike the more the motor has to exert itself, the more the motor exerts itself the more power it uses. This all results in a shorter distance traveled. This isn’t only down to the rider’s weight but includes the cargo they may be carrying too.
Going uphill requires using more energy as the motor is working against both friction and gravity in this situation, rather than just friction when traveling on flat ground. This is compounded by the weight factor above i.e. more weight going uphill requires even more power. Terrain doesn’t just mean hills, and traveling over dirt and gravel, i.e. less grippy surfaces requires more power than traveling on smooth pavements.
Wind and Weather
A tailwind can help to buoy you along, assisting you and increasing your range, whilst a headwind does the opposite, forcing you and your ebike to work harder; thus reducing your range. Wet surfaces, from paved roads to dirt, are also less grippy, meaning that the ebike has to put out more power to push the rider along.
On an ebike takes a much larger amount of energy to attain a speed compared to what it takes to sustain it. Once you’ve stopped and lost your momentum the motor is going to have to exert energy to accelerate off the line and get you back up to the speed you want to travel at.
How hard you pedal directly correlates to how much energy the ebike uses. The more energy you put into the system the less the ebike has to put in. This increases your range. Conversely, the laxer you are with your energy input the more the ebike compensates, increasing its energy input and reducing your range.
Electric Factors - Ebike Range Calculator
The first and most obvious range factor on an ebike is its battery capacity, i.e. how much power it can hold, and we can use this to calculate an ebike’s range. Unless you're riding one of the first ebikes introduced in the modern era, which is highly unlikely, your battery is a lithium-ion battery; the same type of battery that is in your phone or laptop.
After about 1000 charge cycles, around the 2-year mark for a daily ebike user and up to the 5-year mark for infrequent users or “weekend warriors”, you’ll notice that the battery won’t fully charge. This is a natural part of the lifecycle of all lithium-ion batteries. The battery’s capacity won’t drop by a large amount but a reduced capacity means a reduction in available power and, thus, a shorter range. When this happens it’s about time to consider purchasing a replacement battery.
But if we’re talking about a new-ish battery we can calculate roughly how many miles one can get on a single charge. It has been estimated, and tested, that the average ebike battery, with all other factors being neutral or average, can travel about 1 mile per 20-watt hours.
Huh? Yes, we know. A little bit of high school physics needs to be retrieved from the memory vaults here. But it’s easy physics and all you need to do is plug easily discoverable numbers into the equation below.
Voltage (V) x Amp Hours (Ah) = Watt Hours (Wh)
The first two figures are provided by every ebike manufacturer out there. We’ll take our Aventon Level Commuter and use it as an example. If we look at the Technical Specifications and look under Battery we can find that the Level Commuter ebike has a 48V, 14Ah battery. So:
48V x 14Ah = 672Wh
Our general ebike average, with all other factors being neutral or average, gives us 1 mile per 20Wh. So:
672Wh ÷ 20 = 33.6 miles
So, with everything being average, we can expect to get 33.6 miles out of a single charge on our Aventon Level Commuter. If you then take this and factor in the above “External Factors” you might be able to get an even closer approximation of your range. Now you’re an e-bike range calculator!
How much you choose to use the electric element of your ebike to assist or power you in your ride has a direct effect on your range. Zip-around using the throttle and you’ll gobble up power very quickly. But, if you use your pedal assist you’ll get a greater range. If you learn to optimize your use of pedal-assist with your gearing you can extend your range even further; we’ll talk about this in the next section and in our ebike range increasing tips at the end.
One of our recent articles covered ebike gears, and how to use them to your advantage. In that piece, we talked about balancing the human and electrical inputs of an ebike with the gearing and the terrain. If you’re in too high a gear for your situation you and/or your motor are going to have to put in extra effort, burning more watt-hours and more calories. Getting the gearing balanced with your pedal assist level helps you, your motor, and your range!
Tire Choice and Pressure
Slimmer, smoother tires, like commuter tires, are much better at transferring energy into movement than their knobbly off-road cousins; especially if those knobbly tires are fat tires. Tire pressure also plays an important role and under-pumped tires can harm your ebike range score too.
Tips To Increase Your Ebike Range
Now we know the many factors that affect our ebike’s range, let’s use it to craft 6 top tips for increasing your ebike’s range.
Lose The Extra Weight -If it doesn’t need to come it’ll just slow you down.
Fully Pumped Tires -Fully pressurized tires provide the best transfer of power from the wheels to the ground.
Correct Tires -Get tires that suit your purpose i.e. if you ride exclusively on pavements consider purchasing commuter tires instead of the mountain bike style tires you might have.
Correct Pedal Assist Level -Match your desired top speed with a pedal assist level that suits it. Doing so will reduce the burden on the motor because it won’t be trying to push you harder and faster.
Ride Slower -Through our own “Real World Range Testing” we’ve proven that the tortoise always wins the race, that is: the slower your ride the further you’ll go.
A Clean and Oiled Drive Train -The drive train runs an ebike. Keeping in good working order is key to operating at the greatest efficiency.
If you have an ebike you can be your own personal electric bike range calculator. Simply run your battery down to empty when you’re out on an adventure and use the distance covered to work out your own personal range. Do this a few times to get your personal average and then you can see how optimizing for range using the above points can change it.
So if you want to make an electric bike range comparison it can be quite hard if you’re choosing to just review the materials the manufacturer provides. Now, however, you know how to calculate an ebike’s average range yourself you should be able to find an ebike with the range you want
At Aventon, we conduct our own real world testing with each of our ebikes, using a passenger of average weight, 180lb, on averagely flat terrain. We run this on every one of our ebikes, for each level of pedal assist and the throttle function, and publish it on the pages for that ebike. That way people can make an informed decision on exactly which Aventon ebike will suit their needs!