Charging the e-bike battery - here's how!

Charging the e-bike battery properly – it can't be that difficult, right? Yet, people keep asking for instructions. And that's understandable, because after all, an e-bike is an expensive purchase and the battery is one of the most costly components. Naturally, you don't want to make mistakes that could end up costing valuable capacity or ruining the battery. That's why you'll find out everything you need to know about the e-bike battery and its charging here.

Our most important tip right at the start:

Before you ride your e-bike for the first time or charge the battery, you should read the user manual! There you will find specific information about your drive system, and that's important. They help to maintain the battery so that it lasts as long as possible.

How is the e-bike battery charged?

The actual instructions for charging the e-bikes are really brief:

With most e-bikes, you can remove the battery to charge it. However, there is often also the option to charge the mounted battery. If the battery is permanently integrated into the pedelec, you must position it so that you can reach a power outlet.

Remove the battery or park your e-bike so that the cable reaches the nearest power outlet.
If your bike is dirty – which often happens with eMTBs – you should check and clean the contacts beforehand to avoid leaving scratches.
The contacts should also be dry before you plug in the cable.
Charging an e-bike battery is not difficult. Plug the charger into the power outlet and then connect the plug to the e-bike or the battery. Now it’s time to … wait …

One thing you should not do:

Do not leave the plugged-in battery alone for too long! During the charging process, you should regularly check the charge level. Once the battery is full, it should be disconnected from the power outlet as soon as possible.

You don't have to sit next to it and constantly keep an eye on the battery. But it is not recommended to leave the battery unattended overnight, let alone over the weekend, during a trip, or even plugged in all winter.

Once the battery is fully charged, unplug it (and reinstall it if necessary). Important: You should also unplug the charger.
Once the charging port is properly sealed or the battery compartment is closed, you can start your next e-bike adventure
After charging, the e-bike fun can start all over again! Image © Santa Cruz

Can you charge the battery in the apartment?

Where can you plug in your e-bike battery? Not everyone is lucky enough to have a bike parking space in their own garage that also has access to an outlet. Whether you can charge the battery in the apartment mainly depends on whether you can remove it from the e-bike or not.

This consideration therefore plays an important role when buying an e-bike! Especially with the newer models, there are some e-bikes that have a fixed battery. Here, the battery is firmly fitted into the frame, and there is no flap through which it could be removed. If you don't have bike-friendly access to an outlet, you should definitely buy a pedelec where the battery can be removed, otherwise charging will become really complicated!

→ Important! When buying an e-bike, you need to consider in advance where and how you can charge it. In case of doubt, you are more flexible with an e-bike with a removable battery because you can charge it in the apartment, at the office, or in a hotel.

Integrated e-bike battery on green e-bike

With this e-bike, the battery is fixed, so you have to park the whole bike near an outlet! Image © Orbea

If you charge your e-bike outside…

You see more and more e-bikes hanging on power through an open window. There's nothing wrong with that. Just don't forget one thing! Lock the bike with a suitable lock and make sure no one uses the open window to break in!

Where exactly should you charge the battery?

When charging, the battery likes a pleasant room temperature of about 20 degrees. It should not be charged in cold or overheated rooms, or lie near heat sources while charging. Directly on the heater, for example, is not a good place to store it.

And even though the batteries are protected from overheating by a BMS, nothing easily flammable should be near the battery or the charger. Sometimes it is even recommended to charge e-bike batteries only in a room with a smoke detector or under constant supervision. Other experts consider this completely exaggerated. At the very least, you should ensure good ventilation and choose a surface that does not easily catch fire. Not only can the battery warm up when charging (it shouldn't get hot!), the power supply in the cable can also get warm and should be on a safe surface.

When should you NOT charge the battery?

If the battery heats up quickly, you should stop the charging process. Charging is also not recommended on particularly hot days, so you might want to wait until it gets cooler in the evening. When charging the battery on the e-bike, it should be kept dry!

Important! If your battery has fallen or received a heavy blow, you should have it checked first and then recharge it. Even after a severe fall or accident, it is better to be safe and have the e-bike and battery thoroughly checked!

How often can you charge an e-bike battery?

Depending on the manufacturer, a battery lasts about 1000 complete charge cycles before the capacity gradually decreases noticeably.

Even after that, you can of course continue to charge your bike! The battery will then show a full bar after charging, but you will notice that the range of the e-bike decreases. The battery is not broken, it ages, which is unavoidable even with the most modern lithium-ion batteries.

A complete charge cycle is by the way a full charge, so from “almost empty” to full. If you recharge at 50% each time, that would only be a half charge cycle, and it will work more often before the aging process becomes noticeable.

How much remaining range should be left in the e-bike battery? Image © Liv

Does the battery have to be completely empty before you can charge it?

With early battery models, it was repeatedly emphasized that the battery should not be charged "in the middle". Empty it, charge it… empty it, charge it. It was a bit impractical because if you knew exactly that the battery wouldn’t last the next day, you could only top it up quickly with a guilty conscience or first empty it in a night shift. If batteries were only partially charged, the "memory effect" could reduce the charging capacity (more on that below).

Fortunately, this rule no longer applies to modern lithium-ion batteries. It is no longer necessary to wait until a device, your e-bike for example, runs out of juice and shuts down. You can charge at any time and at any remaining charge level, so you can always start with full capacity.

Can the battery be completely discharged before the next charging process?

You can start charging the battery at any point, but there is one thing you should not do: An e-bike battery should not be completely drained. Then the battery can be deeply discharged despite BMS. More on that below.

Do you always have to fully charge the e-bike battery?

If your e-bike has a modern lithium-ion battery, you can also partially charge , that doesn't harm the battery. With nickel-cadmium batteries, which used to be the standard, the memory effect was a threat. You can find more information about this further down in the FAQs.

BMS – the Battery Management System helps you charge the e-bike battery!

To protect the battery from improper handling, all good e-bike drives have a Battery Management System. This smart programming controls and monitors the battery and prevents overcharging or deep discharging of the cells. The temperature is also monitored, so overheating is detected in time. It also helps to dose the required amount of energy or ensures that the charge level is correctly displayed on the screen.

How long does it take to charge your e-bike battery?

Your phone takes a few hours to charge; does the large e-bike battery take longer? If you use your bike frequently, it's good to know how much charging time you need to plan. So – how long does it take to charge the e-bike battery? Unfortunately, as is often the case with e-bikes, there are no clear numbers.

The charging time depends on two conditions: 1. the battery capacity and 2. the charger.

The battery capacity determines the charging time

The more capacity your battery has, the longer it takes to fully charge. Most e-bike system manufacturers provide information about charging times on their online pages or in the manual.

Here are some examples for comparison:

A "small" battery from Bosch with 300 Wh is about half charged with the standard charger in about 2 hours, for a full charge you should allow 5 hours. With the fast charger, the charging time is halved.
The Bosch PowerTube with 750 Wh is about 50% charged in 5 hours, fully charged after 11 hours. With the fast charger, it goes faster, then 2.3 hours is enough for 50% and 6 hours for 100%.
A Shimano Steps integrated battery with 630 Wh takes 2.6 hours for 50%, and in 6 hours it is completely full.
The Yamaha down tube battery with 500 Wh is fully ready for use again after 4 hours.

There are various ways to charge the e-bike battery. For example, with the charging cable directly on the battery. Image © Trek

With the speed charger, charging is faster!

For most e-bikes, the appropriate charger is included. Large manufacturers offer different chargers for their e-bike drive systems. With Bosch the selection is particularly large. There is a “normal” power supply, a “Fast-Charger,” and a “Compact-Charger.” The latter is particularly small and light, making it perfect for on the go. However, it is somewhat slower. At Shimano, there are chargers suitable for the drive series and the region where the e-bike is sold. At Yamaha, there is one charger for all e-bike batteries.

Usually, a “normal” charger is included with the new e-bike. If you want a faster one, you can buy it separately if available. There are fast charging stations and Speed Chargers (or Fast Chargers) available separately, which significantly reduce charging time.

However, you should always use a charger that matches your drive or is approved by the drive's manufacturer. There are third-party chargers, but their use is explicitly not recommended. They can damage the battery or generate dangerously high heat during charging.

Can you charge your e-bike on the go?

If you ride to work every day with the City E-Bike , the remaining range is usually not a problem. Even a small after-work ride can be well planned. When the battery is empty, you plug in the charger and you're done. But when traveling, on bike paths, or on longer tours, the question arises: How do you get new power for your Trekking E-Bike or E-Gravel Bike? There are different possibilities.

There are bike-friendly hotels or guesthouses that cater to the needs of e-bikers. They have charging stations, or at least a bicycle parking space where you can also charge your bike (possibly for a fee). Bike-friendly restaurants or beer gardens also occasionally offer the possibility to charge during a break.

But it is also possible publicly! The network of publicly accessible charging stations for e-bikes is growing and growing. Online, you can find maps showing the nearest charging station, or you can use a navigation app to search at your location. Beware, there are different charging stations! Some have different plug systems available, others simply have a socket, and then you need your charger.

If you want to know how to get the most range out of your battery, you can find a lot of information in our article on “E-Bike Range”!

How to extend the lifespan of the e-bike battery

Batteries prefer it to be comfortably tempered. Temperatures above 30 degrees and frost they don't like it. In the long run, the weather can affect your battery. But it can also happen quickly: Perhaps you've already noticed that your phone gives up faster during a winter bike tour? Here too, the battery reacts to the cold by refusing to work. When you sit in a cozy heated office the next day, the phone lasts longer again. The same goes for the e-bike – the battery provides less range in frost.
Even in cooler temperatures, you should avoid direct sunlight.
It means peak performance for the battery if it has to constantly run at the limit. Too much weight and constantly at the highest level is a severe strain on the entire drive, causing it to age prematurely. But you can prevent damage here. Make sure your e-bike has a drive that fits your touring plans, weight, and so on. Maybe a larger drive is necessary, but it will last longer!
If you don't use your e-bike for a longer period, it is worth storing the battery carefully. It is best stored frost-free and at a charge level between 30 and 60%. You can find more information about this in our blog post “Storing the e-bike battery – but correctly!”

FAQs about charging the e-bike battery:

What does a battery charge cost?

What your battery charge costs naturally depends on what you pay for your electricity. If your roof produces solar power, an e-bike charge costs you “only” the installation of the system. How expensive a full charge with purchased electricity will be depends on the size of the battery and how much remaining charge is still available. There are different estimates, but you can expect 15 to 25 cents.

If you want to be particularly environmentally friendly, you should of course use eco-electricity!

Does the e-bike battery discharge by itself?

Batteries discharge over time, even if they are not powering a device. This happens very slowly, but eventually, even a parked e-bike will be empty. This effect is called "self-discharge” and it is the reason why a battery, if not used for a long time, should have between 30 and 60% charge. This way, it does not self-discharge until deep discharge causes damage.

What does a new e-bike battery cost?

You've always charged the battery according to instructions, protected it from frost, not overloaded it – and yet it doesn't work anymore? That's quite normal. It just ages. If the charging capacity and thus the range are no longer sufficient for you, you can take the following measures:

Get a range extender
Buy a new battery

Since a new battery and also a range extender are not cheap, you can take your e-bike for a service check beforehand. In the bike workshop, you will find out whether the investment is still worthwhile or not. Especially if you bought an e-bike from a renowned manufacturer, the chances are good that it is not too worn out, good e-bikes usually survive several battery lifetimes without any problems!

You should budget around 500 euros for a range extender.

A replacement battery costs between 500 and 900 euros depending on capacity, series, and manufacturer.

What is deep discharge?

Let's assume you leave your e-bike standing over the winter without first charging the battery level to about 30 to 60%. Due to self-discharge, the e-bike's battery drains unnoticed. Eventually, the battery is empty, but winter is still in full swing, you are not cycling, and you don't notice. Then the battery can become "deep discharged." This causes the voltage to drop below a certain value, which can damage the battery. To prevent this, you should occasionally check the battery level of an e-bike that is not used for a long time and charge it a bit if the remaining charge falls below 30%.

The e-bike battery can no longer charge properly – what's wrong?

There are several possible scenarios here…

The contact points of the battery are dirty. If you have ridden your e-bike through mud or puddles, dirt may have been washed into the connection between the battery and the e-bike. This can disrupt the transmission.
The contacts are wet or rusty.
Battery aging is a normal wear phenomenon. The battery may have lost too much capacity. If the bike is a few years old, this might be the case.
Maybe the e-bike battery is deeply discharged? Then you should contact a workshop or the manufacturer.
An e-bike system can withstand a lot, but it can also be broken. If the battery does not charge, you should not leave the bike plugged in for days. Unplug it and ask the manufacturer or where you bought the bike.
Maybe the charger is simply broken.

If your e-bike cannot be charged, there may be an error code on the display or in the e-bike app. If your bike has neither, the indicator light may blink. Then you should not charge it but have the bike checked in a professional workshop.

What is the memory effect?

Today, lithium-ion batteries have become established, as one of their great advantages is the fact that there is no need to fear a memory effect. Older batteries lost capacity when they were only partially charged. These batteries "remembered" the incomplete charge state as a full charge and thus no longer used the stated capacity.

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