How to charge
an
electric bike battery

Electric bike batteries

The lithium-ion electric bike battery is, really, the most important component of an e-bike (along with the motor, of course!). It provides energy to power the bike, and ultimately, it's the thing that makes it an electric bike!

Proper electric bike battery charging is really important to make sure your equipment lasts as long as possible. Using the charger properly and keeping a healthy amount of charge in the cells themselves can help prevent lots of common e-bike battery problems.

How do you charge the battery on an electric bike?

Because every battery is different, you should always read the manufacturer’s charging instructions very carefully before you get started for the first time. If you've just bought a new e-bike, you'll need to charge the battery fully before you use it. Even if there's a little bit of charge in it when you unbox it, don't be tempted to take your new bike out for a spin; it's always best to give it a full charge to set it up properly.

Make sure to only use the charger that comes with your bike to prevent any damage to the battery or the bike itself. Using a non-compatible charger can also potentially be dangerous, so in the event of losing or damaging the charger, make sure to contact the manufacturer directly for a replacement.

Take care not to overload any plug sockets when you're charging up your e-bike, and never leave a battery plugged in unattended or overnight.

When should you charge your e-bike battery?

The first rule is that e-bike batteries shouldn't ever be pushed to their limits. The amount you charge the battery is the most important factor when it comes to prolonging its life. An e-bike battery should only be charged when its capacity is between 40 and 70%.

If possible, try to make sure that the battery never discharges completely down to 0%; this is called deep discharge. After a long bike ride, it's best to pop your e-bike battery on to charge immediately. And even if you aren’t going to use your e-bike for an extended period, it’s still important to charge the battery from time to time.

Deep discharge is the most common cause of e-bike battery cell degradation and causes lots of the most common e-bike component problems. In the case of a major battery malfunction or failure, usually the only solution is to recondition the e-bike battery or replace it with a new one. In either case, if you notice any problems with your e-bike battery, get in touch with your local e-bike store and have a specialist take a look.

Keep electric bike tyre pressure in mind when you're charging the battery too; low pressure means the battery consumes more energy, so make sure to check regularly.

How often can an e-bike battery be charged?

A lithium-ion battery is generally capable of between 500 and 1,000 charging cycles. That said, the battery will begin to lose its charging capacity slowly after 500 cycles, leaving it with around 60 to 70% of its original capacity. To maintain this capacity for as long as possible, it's really important to follow the proper electric bike charging process and to use only the correct charging cable. Using another charger can cause your battery to degrade even faster, break down completely, or void your e-bike warranty.

Just as avoiding total discharge is important, it's also vital to avoid overcharging. Make sure to recharge the battery immediately after going out on a long bike ride, and remember to give it a charge every now and then, even if you haven't used it for a while. A battery is always discharging gradually, even when it's not being used, so make sure to regularly charge a battery, even if it's in storage.

How often you have to charge your battery depends on the daily battery capacity, which you can read on the handlebar display. By charging when the capacity is between 40 and 70%, you’ll prevent overcharging and deep discharge and, therefore, help maintain maximum battery life for longer. You don't need to wait for the battery to empty before charging it, either.

How long does it take to charge an electric bike battery?

Typically, it will take around 3–4 hours to fully charge an e-bike battery, and usually no more than 8. However, there are a few things to bear in mind: obviously, the charging time will depend on the capacity of the battery and the type of charger provided, so the manufacturer's estimates will likely be pretty accurate.

Since avoiding overcharging is so important, you probably won't need to keep the battery plugged in for long periods of time anyway. The battery doesn't need to be completely charged every time anyway, and partial charging won't have any consequence on the cells' storage capacity.

Batteries generally take longer to charge if they are completely empty or if the temperature is low. It will also probably take longer to charge a battery if it's been inactive and kept in storage for a long time.

What to look out for when charging your electric bike battery

Only charge your battery at room temperature, and keep an eye out for overheating, particularly in hot conditions. Equally, colder temperatures can also be damaging for the battery cells, so never charge a battery at sub-zero temperatures. Ideally, find a place in your home that is dry, dark, and neither too cold nor too hot. If you want to head out on your e-bike on a particularly cold day, put the charged battery back into the bike just before you set off.

When charging at a wall socket, make sure that you clear the area of any flammable materials and keep the socket clear and dry. If there’s a big difference in temperature between outdoors and indoors, give the battery about ten minutes to adjust to room temperature before attaching it to the charger. Otherwise, the battery could expand and even ignite while charging.

After charging, make sure to disconnect the battery from the power supply right away. Never leave your battery plugged in for more than 24 hours. The safest way to disconnect the battery from the power supply is to unplug it from the mains by pulling directly on the plug; the cable is generally more fragile than the plug itself.

Check out our electric bike batteries guide to learn more, or visit our Electric Bike Knowledge Hub for even more information.