You don’t want your hard pedaling to go in vain when riding an electric bike. So can you charge your electric bike when pedaling?
There’s a lot more that goes into it than a simple answer, but we’ll start here: yes, electric bikes do charge when pedaling depending on your electric system and the type of electric bike that you have.
This is called regenerative pedaling, and is usually offered on premium electric bikes, though many manufacturers are playing the pricing game and gradually lowering the cost of regenerative pedal bikes as a whole.
Basic electric bikes just have the three main components of an electric assist, but some of them come with dynamos that produce a small electric current that slowly recharges your battery as you pedal.
It isn’t enough to simply answer that question: let’s delve deep in and see how the system works, and the effects of pedaling, braking and your electric assist system.
What is an Electric Assist?
Electric assist is the term used to separate the functions of your electric bicycle. Your electric assist consists of three different features on your bike that you are already aware of.
- Motor: When you kick on the throttle or electric assist, this is what’s going to force your bike to move along.
- Battery: All of your energy storage, generally located in a small 8” x 10” box in the frame underneath your seat.
- Display: The display system allows you to regulate features, such as different levels of electric assist.
These three pieces make up the electric assist. Without them, you’d just be riding a normal bicycle. They interact with the standard parts of your bike, like the drivetrain and brake system. Electric assist isn’t just a black-and-white thing though, it can be used in tandem with pedaling.
Some bikes have different modes, where you can use a small amount of electric assist to help you cover obstacles without going into full throttle. If you just need a little bit of boost to get the job done, select the appropriate mode on your electric bike to kick things up a notch.
Does my Electric Bike Charge in Throttle Mode?
Throttle mode is best summarized as when your feet aren’t needed on the pedals at all, because the motor is doing all of the work and pulling the bike along. Even if your electric bike has different modes to assist you, they are different from throttle.
Your bike isn’t going to charge in throttle mode, because you can’t just recycle the energy output like that. When you pedal, you’re creating your own kinetic energy that can be transferred into the lithium-ion battery.
Standard bike batteries generally can’t intake and output energy at the same time, you would need a more sophisticated system to do that (such as a car battery).
When do Bikes Stop Providing Electric Assist?
Most bicycles are using very lightweight motors, batteries, and charging methods. That’s why it takes so long to charge your battery (more on that later). Since manufacturers try to keep the cost of electric bikes down as much as possible, those lightweight components can’t sustain a charge past a certain MPH.
You can expect your electric assist to stop around or after the 20 MPH mark. This doesn’t mean you’re causing additional stress to the electrical system whatsoever, it’s just at full capacity for the amount of energy that it can return to your lithium-ion battery.
How Does it Work?
There are a lot of generations of different electric bikes, but most of them use a similar method to recharge the battery and conduct electricity during use.
Through the kinetic energy that’s created when you pedal, your drivetrain will build up enough friction and release energy back into your lithium-ion battery. For the most part, lithium-ion batteries are the very best solutions to harvest power that you create through kinetic energy.
So pedaling helps, but the main way that an electric bike begins to build up charge is by braking. In your electric bike braking system, there’s a little sensor that goes off to alert the rest of the electric system. When you activate your brake, your motor can flip into something that’s best described as reverse mode.
During this, the forward motion of your bike transfers friction and heat into the drivetrain, which is utilized by reverse mode. In a traditional bicycle, that heat and friction would just slightly warm the chain and brake pads, and that would be the end of it. Most electric bikes reverse engineer the energy and store it in your lithium-ion battery.
The brake method is actually going to provide you with more of a charge than pedaling alone. During pedaling, kinetic energy doesn’t 100% fully transfer into stored electrical energy in your lithium-ion battery.
Much of it is lost through the process, which is why we don’t use kinetic energy as a widespread global clean energy source. Pedaling alone can require a lot of time to reach a proper charge.
Does Regenerative Braking Damage my Brakes?
Actually, your brakes should last longer with a regenerative system. Standard bicycle brakes aren’t built to withstand intense use; they’re marginally used because you can usually control your speed and momentum fairly easily on a standard bike.
When there’s a motor involved and speed up to 30-35 MPH, that’s when things get tricky, and so manufacturers make their regenerative brakes with a lot more power.
Your brakes are going to wear down as much as you use them. If you’re taking the same quiet path to work every day on your electric bike and you only need to brake when you reach your destination, you’re not putting much stress on the system.
If you’re in crowded, bustling city streets that demand constant vigilance and awareness, then you’re going to use them more often and wear them down faster.
How Much Battery Can You Charge While Pedaling?
It’s all about how much power you put into it, the time spent, and the age of the battery that’s being used. On average, electric bike batteries last for about five years before you should seriously consider replacing them.
The closer your battery is to that five-year mark (provided that it’s been used sufficiently so the battery doesn’t lose its charge), the longer it’s going to take to sustain a proper charge.
You can charge your battery back up to full, but it’s going to take some time. Charging through pedaling is an excellent way to reduce any carbon footprint that you might incur by traditional electric charging, but it’s also a good way to lengthen the duration of your ride.
Depending on your settings, your speed, and how much consistent pedaling you do during your commute/transit, your battery can be fully charged, but there is a catch.
Most electric bike batteries can take about six to eight hours to charge through standard charging methods, but you’d have to maintain a speed of about 15 MPH for eight to twelve hours to receive a full battery from pedaling alone. Pedal charging comes in handy when you pair it with standard electrical charging. Let’s say you have a one-hour commute (thirty minutes each way).
If you’re putting the pedal to the metal to get there, you could receive about 10%-15% of your total battery just during transit. That’s roughly one less full charge per week, and 10%-15% less time spent on the charging cable in between uses.
All Battery Charging Methods Range in Efficiency
You’ll see wide gaps in information, like 3.5-6 hours for a charge, or even as we listed eight to ten hours for pedal-assist charging. That’s because batteries are fickle and don’t charge 100% perfect all the time.
When you plug your phone in to charge, you’ve likely said to yourself once or twice “That charged faster than I thought,” or “Why is this taking longer than usual?” It’s simply not a perfect process and will vary, so don’t jump to conclusions if your new-ish battery isn’t charging as fast as you would like.
There’s charging efficiency, and then there’s the efficiency of the battery itself, which will wane over time. It’s safe to assume that your electric bike uses a lithium-ion battery, which are the most popular type of batteries that you can find in almost any rechargeable appliance or gadget (just look at the phone in your pocket).
Standard electric bike lithium-ion batteries are able to be fully recharged about 500 times before they start losing their efficiency.
After that point, you’ll experience longer charging times and less of a charge after each use. After that rough 500-use mark, your battery will only retain about 70%-80% of what it originally could, effectively bringing down the efficiency of your electric bike.
You can use a battery tester to find out how many volts your battery is retaining. Just charge it for the full amount of time that you normally would, and connect the tester to it to see what you’re dealing with. As a rule of thumb, you should properly dispose of your battery and replace it when it falls below 50% operating efficiency.