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The Short Answer
Electric bikes do not generally charge when pedaling. Regenerative braking can generate some energy, but it is not commonly used. E-bikes are charged by connecting the battery to a power source. Charging while riding creates resistance and is not practical for most riders.
Electric bikes are versatile machines offering pedal assistance to support your abilities and leg power. They usually recharge the same way as other small portable electrical devices. The battery pops off the frame and into the wall socket via a cable. In a matter of a few hours, you’re topped up.
Electrically-supported transport through traditionally motorised vehicles offers forms of energy regeneration when in use. Car manufacturers are falling over themselves to advertise this feature as ‘free recharge’. Can the makers of e-bikes promise the same?
Do Electric Bikes Charge While Pedalling?
Most electric bikes do not charge when pedalling. The reasons for this come from the physics lab, the accountancy textbooks and the heritage and dynamics of why so many of us love cycling. Recharging in use is inefficient, expensive and counter-productive to many. But it can be done.
Let’s start with the essentials. Any charge that might be normally obtained when you are riding comes from regeneration of that energy created as you travel. We probably want all our effort to go into forward momentum, not saving it for later use.
It’s also shown that regeneration through pedalling costs a lot of lost energy in the transfer process. In the main therefore, any recharge comes from braking. Friction and heat generated when you slow yourself down can be converted into energy and stored for later use.
But you need a more complex type of motor to do this. And the science part means that the motor has to always be operating. And if it’s always operating, it creates resistance to your pedalling.
The two main types of electric motors installed on your bike – mid-drive and geared-hub – disengage when not in use. You therefore can coast or use your own energy to propel the bike forwards without any resistance. If you’re thinking of buying a complete e-bike, it will usually be built with a mid-drive or geared-hub motor.
There are some designs which promote charging whilst backpedalling, drawing on the KERS system used in Formula One cars.
Do E-Bikes Charge Themselves?
E-bikes do not charge themselves, in practice. The mid-drive or hub-gear set-up is the mass manufacturer’s chosen method. It’s cost-effective, keeps the weight gain down to a minimum and offers pedalling assistance as opposed to full motorised control. The tech for self-charging is in its infancy.
Most commentators see regenerative braking in cycling as a false economy. The regenerative power created might only get you a maximum of 10% additional energy and the weight and complexity of the motor required to do this is seen as unnecessary.
In the leisure market, it’s pleasing to see that e-bike use is no longer seen as cheating as society pushes us to make a different choice in how we cover that first or last three kilometres or so to and from our homes.
Most leisure users enjoy the boost that assisted pedalling offers them for when they face a headwind, or a difficult climb. But many still opt for traditional pedalling for the majority of their ride. Whilst charging during riding is possible, it would for many of these casual riders be off-putting, as charging while riding creates resistance and slows you down.
That said, it’s clear that there is a market for the commercial use of cycles as a form of transportation. This will open up new possibilities for electrically-assisted functional bicycles. Cargo bikes are increasing in popularity and some users may want 100% electric charge with no personal input and a longer range with less-frequent stops for charges.
How Do Electric Bikes Charge?
Electric bike battery charging is as simple and straightforward as it is for your communication devices or bike computers. Check your user manual first. You plug the battery charger to a power source and connect it to the battery. Then turn it on. Most are good for up to 1,000 charge cycles.
Most batteries can now be removed from the bicycle, unless they are built into the frame. It’s better to run a recharge cycle indoors to preserve the battery life. You’ll find most battery packs now pop off their housing to do this.
It’s a good idea not to overcharge your battery and many people will set a timer on their phones for the right number of hours needed. Some opt to buy a spare so that they can always have a juiced-up one available. Most batteries should stay between 30%-80% charged as a rule.
How Do Electric Bikes Work?
E-bikes, as they are more commonly known, are a variant of the bicycle which can be powered via an electric motor. The motor is powered by a rechargeable battery. Electric bikes can be ridden as an everyday machine using 100% of your own energy with the choice of motor-assisted pedalling.
The motor is usually found just underneath the cranks in the middle of the bike or positioned inside the hub at the centre of the wheel.
The mid-drive motor receives a current which assists the manual turning of the pedals to power the bike. It’s a smooth process which when switched on normally activates just after you start pedalling. It can detect the effort you are putting into turning the pedals once it has established the power level you have set the motor to provide the assistance.
The hub-motor is set directly onto a wheel of the bike, usually at the rear. It is further divided into the direct-drive or the gear hub motor. The current from the battery causes a rotor inside the hub to spin and drive the whole wheel forwards. Without needing to detect anything, the power is available immediately. Some hub-driven bikes have optional throttles.
If you are considering a first e-bike purchase, it’s important you understand local certification and the laws around ownership. There are a number of limits including the maximum power of the motor, how that power is distributed and speeds that can be reached before the motor must be cut. Check your own laws first before you buy.
