When people think of regenerative braking, they probably associate it with a feature on electric cars. Regenerative braking on electric cars is promoted as a feature that will boost your range because the battery starts to charge, rather than drain, every time you take your foot off the accelerator, or depress the brake pedal. In some EV’s, this is a feature called ‘one pedal driving’, whereby, the vehicle slows down enough by taking your foot from the accelerator, that you will rarely need to apply the brake pedal to slow the car down quicker.
On a smaller scale, regenerative braking on ebikes, or electric bicycles, works in a similar way. When you apply the brakes on your ebike, the motor stops assisting you forward, and instead turns into an electricity generator, and starts to create power that will flow back into the battery to top up the remaining charge level. This can help extend the range available by replenishing the battery to provide more motor assistance when required.
What Is the Purpose of Regenerative Braking?
There are a few reasons why regenerative braking is a great idea and an innovation that is a positive asset to have on your ebike.
Firstly, it extends the range of the battery. The ebike range of most modern electric bikes is not so great, so even having a little boost to the battery as you go, can extend your range enough to make it worthwhile. Some manufacturers may claim up to 10% of battery capacity can be recovered with regenerative braking on a journey, though typically this will probably be a lot less. There are so many variables to take into consideration to come up with a figure that would be remotely accurate, but needless to say, whether it is 10% or just 3%, you are still extending your range and ensuring you have powered assistance from the battery for longer.
Secondly, it is free electricity; you are not paying a dime for every extra bit of power that tops up the battery. You are gaining a boost of battery power every time you slow down. If you are forever climbing and descending hills where you ride, then this could make a substantial contribution to your powered range, and also save you money, which accumulated over time, could be a pretty decent cost saving.
Thirdly, if you are using the motor to slow down your ebike, as it will do while in regenerative braking mode, you are not using your ebike brakes as much as you would normally have to, and when you do, you are not applying the brakes as forcefully. This means more savings for yourself as consumable brake parts will need replaced less frequently, and with less wear and tear on the whole braking system, you should expect that other parts of the system will fail less often, or not at all.
See Also: Can I Solar Charge an Electric Bike?
How Does Regenerative Braking Work on Ebikes?
Most traditional ebike brakes work when you pull on the brake lever, then it forces brake pads to clamp down on either side of a brake disc attached to the centre of the wheel. This creates friction between the pad and the disc, which also creates heat, and wear on the brake pads. Regenerative braking systems work either with the braking system, or independently, usually with a switch the rider can manipulate, to convert the ebike motor from a mode of driving the ebike forward, to a generator state, whereby the motion of the wheel turns the motor to generate electricity, rather than the motor turns the wheel to drive it forward. This generated electricity is then fed back into the battery for reuse when the motor reverts again from generator mode to powered assistance mode.
Do Ebikes Charge While Going Downhill?
By utilising the switch on the handlebar to turn on the regenerative braking system, you will turn the motion of your ebike motor into generator mode, and the forward motion of the ebike will begin to create electricity and charge the battery. If you are on a flat stretch of road, or on an uphill slope, then your ebike will shortly come to a stop, as the motor is no longer assisting you forward and peddling in this mode will be physically draining. This mode though, is excellent for going downhill. And the longer the downhill stretch the better. Instead of braking to steady your speed as you descend, the regen braking will do so, and the longer it does this, the more electricity is generated and returned to the battery.
Is Regenerative Braking Worth It on Ebikes?
Some may look on ebike regenerative braking as a sales gimmick, or something that at the end of the day has made very little difference to be meaningful in any significant way. Or, perhaps, the fact that ebikes fitted with regenerative braking systems tend to be more expensive means that any savings made may be a drop in the ocean to the extra cash paid out.
The fact is, though, that it is a system that is proven to work, and can save you money over time. If you combine the savings on the free electricity you created, plus take into account the savings in, for example, brake pads you will replace less over time, then over a period of a few years this can amount to something meaningful that is definitely budget friendly.
Ebike technology is improving all the time, the only constant is that nothing will stay the same. As motors improve, and battery technology advances, I am sure that systems like regenerative braking will improve also; efficiency will increase, and that 10% manufacturer claim of battery power that can be recovered through regen braking may turn out to be a vast under-estimate. As time goes on and regenerative braking develops, it should begin to be seen as an essential feature, rather than a desirable option. We will have to wait and see.