The range of an ebike is the number of miles it can travel before the battery runs out of juice and stops powering the motor. As you may guess, the main factor to influence ebike range is the battery itself. We have talked about other aspects concercing ebike batteries in an other article. Here we will be mainly conerned about trying to explain the many factors to take into consideration if you want to know how far you can go on an ebike.
The battery: watt-hours
The capacity of an ebike battery is mostly measured in watt-hours (Wh). Most producers of ebikes and ebike batteries clearly state the Wh value of the battery. If they don’t, you can easily calculate this value by multiplying the voltage (V) by the amp-hours (Ah) of the battery. For instance, a 24V, 8Ah battery has 192Wh; a 36V, 8Ah battery has 288Wh; a 36V, 10Ah battery has 360Wh, and so on.
The more Wh your battery has, the farther you can travel on an ebike (all else being equal); however, a battery with a bigger capacity will also cost more, and weigh more.
As a rule of thumb, you can divide the Wh value of your battery by 12 to find the number of kilometres you will be able to travel on a typical city route, with frequent stops and starts, and some easy ascents. For instance, a 360Wh battery will let you travel about 30km; however, this is just a rough reference, as you will understand by reading the following paragraph.
Other very important factors to influence ebike range
There are a lot of things to consider when trying to estimate the range of an ebike. There’s a huge difference in terms of range when all the following factors work in your favour or against you.
- Level of assistance. Most ebikes have 3 to 5 levels of assistance. It is obvious that when you use a very low level of assistance (that is, when the motor adds just a little bit of power to that delivered by your muscles), the range will be much better than when you go “full throttle”
- Going uphill or downhill: the steeper the ascent, the lower the range. If you plan to use your ebike on a route with many uphill sections, make sure to test it thoroughly (for example by renting it for a few days) before buying it. Your own pedalling effort can become decisive in such situations, especially if the ascent is long and steep. You will not make such a strenuous effort, but you will have to “help” the motor.
- The weight of the cyclist + any other item attached to the bicycle. Especially when going uphill there is a huge difference between a 60kg cyclist carrying nothing but herself, and a 95kg cyclist with a pannier full of a week’s worth of shopping.
- The conditions of the mechanical part of the bike. If the chain and gears are not well oiled they will cause a higher friction and reduce the range. Similary if the tyres have not enough pressure, or – worse – if the brakes rub against the rim (or the disc in case you have disc brakes).
- Wind: as any cyclist knows, going against the wind can be a big challenge, and reduce the range of your ebike.
- The surface you are riding on: a well-paved road ensures a greater ebike range, compared with riding on a dirt road.
- Battery age: with time, a lithium-ion battery will start to degrade, and you will be able to extract less “juice” from it than at the beginning of its life. If you choose a high quality battery, you may start to notice a small decrease in range after a couple of years, gradually worsening until you have to replace the battery after 3 – 3,5 years. If you decide to “save” by buying a cheaper battery of worse quality, it may start to degrade after just a few months. This is also the reason why you have to consider carefully the warranty on the battery that the producer or the seller offers.
To help you understand the importance of the many different factors concerning ebike range that we have just mentioned, consider the image above, which shows the range of a typical Bosch ebike. Eco, Tour, Sport and Turbo are the four levels of assistance. For each level, the dark bar shows the range in optimal conditions, while the light grey bar shows the range in the worst conditions. You can easily see the difference between riding on the Eco mode with optimal conditions (190km of estimated range), and riding on the Turbo mode with the worst conditions (40km of estimated range).
More advice concerning ebike range
There are some factors that you can influence, and others that you cannot. You cannot change the steepness of the route you are taking. You can however ensure that your ebike is in excellent order (mainly transmission, tubes and brakes), and you can choose to use a little less power on a flat section to save energy for when you go uphill.
When choosing an ebike try to test it as much as you can, to make sure that it is possible to travel your desired route. Do not save on the battery, and when in doubt between two models, always go for the one that has a battery with a higher Wh value. Moreover, pay attention to the system for recharging the battery, which has to be as simple and flexible as possible: you don’t want a bike whose battery can be recharged only when attached to the bike itself, and you don’t want a battery which puts you into trouble when you want to remove it from the ebike. For instance, at the end of your morning commute you might want to remove the battery from the ebike and take it upstairs in your office to recharge.
If you use your ebike in an intelligent way, resisting the temptation to rely only on the motor, you will make a healthy light exercise, and you will find that your ebike range can be much better than what you thought.