Electric Bike Battery Guide

Last Updated on May 17, 2023 by Matt

chart representing the relationship between voltage and capacity in an electric bike battery test

An electric bike battery is among the vehicle’s core elements and is responsible for powering the motor to propel the bike forward. Its capacity, voltage, and overall condition decide how fast and how far your electric bike can take you.

If you don’t know much about what to look for in an electric bike, I recommend you start with its battery. Knowing everything about the battery can give you a good idea of the bike’s overall performance, which will help you decide what ebike is better for your regular commute.

Electric bike batteries – what you need to know

Electric bikes are fitted with lithium-ion batteries either enclosed inside the bike or externally fastened to the frame. On average, an ebike battery can last between 2-3 years, but its life can be extended up to 5 years if you take good care of it. They come in different size options, with voltages ranging between 24 volts and 52 volts. Typical electric bike batteries can be completely charged within 2-8 hours, depending on how high their capacities are. Most capacities range between 250 to 1000 watt-hours (Wh).

What kind of battery does an electric bike use?

electric bike battery

Electric bikes typically have lithium-ion batteries because they store more energy than other battery types. They’re lightweight, which makes it easy to maneuver and handle the bike. They are ideal for electric bikes because they charge quickly, which is extremely convenient if you use the bike for regular daily commuting. 

You can easily propel the bike forward and ride it for long distances without getting tired.

Lithium-ion batteries are also popular because of their longer lifespans. You can get hundreds of charge cycles from them before they start to degrade and make the electric bike less efficient. 

You can also extend their life with the right charging habits.

Which battery is best for an electric bike?

The best battery for your electric bike depends on your preferences and needs as a rider. A high-capacity battery will give you a better range, but will also be more expensive and make the bike heavier to carry. On the other hand, a low-capacity battery will be lighter and cheaper, but at the expense of a lower range.

If you plan on using your electric bike for hilly commutes, chances are you’ll be using its pedal assist and throttle features quite a lot. These features drain the battery quicker, so a low-capacity battery wouldn’t be the right option. The larger the battery, the easier it will be to ride on steep hills.

If your regular commute consists mostly of flat ground and shorter distances, a low-capacity battery will do the trick.

Note that if you ever decide to change the battery of your electric bike, you can’t pick one at random. The battery must be compatible with your bike’s existing motor and controller, notably its voltage.

Electric bike battery specifications (voltage, charge, and capacity)

The specifications of an electric bike battery, like voltage, charge, and velocity, can tell you a great deal about the electric bike’s overall performance. 

Electric bike battery voltage

yellow voltmeter showing Voltage with cables

Voltage is responsible for pushing an electric current through a circuit. This basically means that a higher voltage will provide more power to the bike and increase its accelerating capability. 

In an electric bike, a higher voltage will result in higher maximum speed, but the battery will be heavier, more expensive, and will drain quicker.

Voltage is denoted by V on specification sheets and is measured in Volts.

Typically, most electric bikes have voltages of 24, 36, 48, or 52 Volts. A high-voltage battery means more efficiency and power, so it’s used in more high-performance electric bikes.

Electric bike battery charge

Charge is a value that represents how much electrical energy an electric bike battery can provide at a given time.

An ebike’s battery charge is measured in watt-hours (Wh).

More charge means more range and a heavier, more expensive battery. 

Electric bike battery capacity

An electric bike’s battery capacity is the overall energy the battery can deliver before your electric bike needs recharging. It’s interrelated with the charge of the battery. 

The battery capacity of an electric bike is measured in ampere-hours (Ah).

Most ebike batteries have a capacity ranging anywhere from 8Ah to 20Ah, but some higher-end models can even have values beyond 30Ah. In my experience, a battery capacity between 10 Ah – 15Ah works well for regular city commutes.

A 10Ah battery can last a good 25-40 miles / 40-64 kilometers before needing a recharge. For longer commutes, a 15 Ah battery gives a range of 60-70 miles / 96-112 kilometers. 

If you use your own effort to pedal, you can conserve some of the battery and increase its range.

Are electric bike batteries safe?

closeup of a high-quality electric bike battery

Electric bike lithium-ion batteries are generally safe to use and have a reliable design. 

They’re pretty much the same ones that are used in smartphones and laptops. To ensure the safety of your battery, always use a charger from the same manufacturer. Its design will be compatible with the bike’s other specifications.

It’s normal for lithium-ion batteries to generate heat as they are used, but they should never overheat. 

Additionally, you should keep a few other associated risks in mind. 

Avoid overcharging the battery because it can overheat and cause a fire. Even if the overheating doesn’t escalate into a fire, it can still speed up the battery’s degradation.

If the battery gets wet, it could short-circuit. 

In case it gets physically damaged, be aware of any flammable chemical leaks. 

To prevent any of these hazards, I recommend following the manufacturer’s guidelines regarding the safety of your electric bike’s battery. 

Avoid storing your battery in extreme temperatures, and regularly check for any damage. 

If your ebike has an external battery, waterproof it by using a water-resistant bag or enclose it in a durable casing.

Some battery designs have an in-built battery management system that prevents the battery from overheating, short-circuiting, and overcharging. 

How do you charge an electric bike battery?

Charging an electric bike is as easy as charging any other electronic device. 

If your bike has an internal battery, there will be a port for you to connect the charging cable. Connect the adapter end of the cable to a power outlet and turn it on to start charging.

You can charge external ebike batteries with the same method or remove them to charge them separately. 

If you have multiple batteries for your electric bike, you can use one while the other charges. 

External batteries are usually locked onto a bike and come with a key. Use that key to unlock the battery off of the bike and connect it to the charger. Once it’s completely charged, you can lock it back onto the bike.

How often should I charge my bike battery?

This depends on how much you use your electric bike. I recommend charging your electric bike every time you get back from riding it, so you always have a full charge for your next ride. 

Your charging habits can play a big role in extending or shortening the life of your bike. The trick to increasing its lifespan is not letting the battery discharge completely. Try to charge the battery when its capacity is between 20% to 80%. 

If you plan on storing the battery, ensure it’s at least 50% charged, and the storage area is cool and dry.

How long does a bike battery charge last?

How long the battery’s charge will last depends on several factors. These include:

  • the battery’s capacity
  • the level of pedal assist you use while riding
  • how much you ride your electric bike on full throttle mode
  • terrain condition
  • weight of the rider and additional load

On average, most batteries last a good 20 to 100 miles before needing a recharge, but higher-capacity batteries can give you an even higher range.

Pedaling yourself can help conserve battery. Using a higher pedal assist level will drain the battery quickly. Riding the bike on full throttle, without any pedaling, will drain it even quicker.

I recommend you use the pedal assist and throttle features wisely and conserve the available battery capacity.

How long does an electric bike battery last?

Depending on the quality and brand of the electric bike battery, a battery can last between 2-5 years. On average, you can get between 300 to 1000 charge cycles. Higher-end electric bike batteries may last longer, often between 7 to 8 years.

That being said, there is no definite way to determine how long your battery will last. The manufacturer’s provided lifespan is usually a good estimate, but the actual lifespan can vary significantly depending on how you take care of the battery.

How do I maintain my electric bike battery?

I’ve found the following tips extremely effective at maintaining my electric bike batteries for an extended lifespan.

Never let the battery discharge completely

Lithium-ion batteries aren’t designed to discharge completely. Their degradation speed can increase if they go below a safe voltage level. 

Going into a deep discharge will cause irreversible damage to the battery, and it won’t be able to hold as much charge as it did before.

So, it’s recommended to always keep the battery level above 20%.

Avoid exposure to extreme temperatures

Exposing your battery to high temperatures can decrease its lifespan significantly, and overheating can also cause a fire. Cold temperatures can also reduce the battery’s performance, so it’s recommended to keep your ebike batteries in a dry and cool place.

Don’t overcharge 

If you overcharge your electric bike battery, it will continuously discharge the charge to a slightly lower battery level than full to continue charging. These poor charge cycles will reduce the lifespan of the battery significantly. 

Choose an ebike with a battery that has an in-built battery management system (BMS) to prevent overheating, overcharging, and over-discharging.

If yours doesn’t have one, you can always set an alarm on your phone for around when the charge is expected to complete.

Charge the battery regularly

charging an electric bike battery with a charger

Lithium-ion batteries can tend to degrade if they aren’t used for extended periods. They decrease in capacity and can even discharge completely. 

So you should regularly charge your electric bike battery even if you don’t use it. This will keep the cells active and maintain their performance.

Only use the manufacturer’s provided charger

An electric bike’s specifications can vary according to the brand and model.  So, always use the manufacturer’s provided charger for your electric bike.

Using an incompatible charger will not only mess up the charge cycles of your ebike battery, but its battery management system won’t work either.

If your original charger gets damaged, get a new one from the same manufacturer.

Regularly inspect for any damage

Regularly check your battery for any physical damage or corrosion.

Catching the damage on your ebike battery early saves it from turning into a major problem. It also saves you expensive repair or replacement costs. 

Observe how long it takes the battery to charge fully and how soon it discharges when you use it. If you think the battery performance has significantly degraded, have a technician check it out to detect the problem.

Reduce the load on your bike

The combined weight of your bike, your own, and any backpack you carry can strain the battery because it’ll need to provide more energy for the motor to propel the bike forward.

So, get rid of any unneeded bike accessories and only carry what you absolutely need.

How do you check an electric bike battery?

For a simple check of your electric bike battery, first make sure the bike is powered off. 

Then remove the battery from its compartment and inspect it for any signs of physical damage like cracks. Check that the connections and terminals of the bike are clean and free from any dust or corrosion.

If there is any crack in the battery, clean the area to remove any dirt and fill it with any adhesive designed to repair plastic. 

Clean all the terminals and connections and fit the battery back into its compartment on the bike.

How to test an electric bike battery with a voltmeter or a multimeter?

Testing your electric bike battery with a volt meter is a simple process that lets you know about the battery’s health. To test your battery, follow these steps:

  1. Before the test, fully charge your electric bike.
  2. When charged, ensure the bike is turned off, and remove the battery from its compartment.
  3. Set your multimeter or voltmeter to measure DC voltage.
  4. Connect the meter’s positive lead with the battery’s positive terminal, and the negative lead with the negative terminal. Then turn the battery on.
  5. Once a reading is displayed on the meter, compare it to the battery voltage specified by the manufacturer. If there is a significant difference, the battery may be damaged. A minor difference means the battery is in a healthy condition.

See this video for more instructions.

When do I need to replace my electric bike battery?

An ebike battery can last between 2-8 years, depending on its quality, how it has been used, charging habits, etc. 

If your ebike battery is close to reaching its estimated lifespan and shows the following signs, it could be time to replace it:

  • Your electric bike not turning on is a dead giveaway that the battery has run its course and needs to be replaced.
  • The battery is taking longer to charge than it usually does.
  • It has a reduced range, even after starting the ride with a full charge.
  • Bulges and swelling in a lithium-ion battery are major indicators that it needs to be replaced.

How much do electric bike batteries cost?

An ebike battery can cost anywhere between $200 to $1000 or more, depending on the battery’s capacity, brand, and quality. Getting a cheaper ebike battery may seem tempting, but they don’t last as long and will cost you more money in the long run when the battery needs to be replaced.

Additionally, cheaper batteries usually don’t perform well and have a shorter range. They also decrease the power provided by the motor.

A battery is one of the most important parts of an electric bike, if not the most important. I recommend investing in one of high quality from a reputable manufacturer with a warranty.

Can you upgrade your electric bike’s battery?

Yes, upgrading your electric bike is a common way to increase your bike’s range and performance. The upgraded battery should be compatible with the other electronic components of your bike and meet their specifications. 

Consult your ebike’s manufacturer for a better idea of what your upgrade options are and if the upgrade will void any standing warranty. 

The upgrade may require changes in some electrical connections, so you should probably consult a professional to help you out.

Can you add an extra battery to your electric bike?

Adding an extra battery to an electric bike is a common customization method for riders looking to increase their vehicle’s range. Consult your electric bike’s manufacturer to decide what battery to add to your bike.

The process of doubling up on your ebike battery involves connecting both your batteries in parallel, and then connecting them to the bike. 

If you aren’t skilled in altering the electrical connections, it’s better to contact a professional than risk major damage.

Is an electric bike battery waterproof?

Most electric bike batteries are water resistant, but the protection level can vary depending on the brand. It’s always a good idea to go ahead and waterproof the electric bike battery yourself as well for an extra layer of water protection. Especially when the bike has aged and the original waterproofing isn’t as effective. 

Use a water-resistant bag specially designed for batteries to protect yours from rain and puddle sprays. You can also enclose the battery in a case and cover it in waterproof tape or spray.

How to store my electric bike to keep its battery safe?

Always store your bike in an indoor, cool, dry place like the shed or garage. 

If you plan to take some time off the electric bike, store its battery in a dry and cool place in your house. Before putting the battery away, ensure the battery is at least near 50%. The battery level may further reduce while stored, so check on it every few weeks and charge it if it goes under 20%. 

Can you use an electric bike without a battery?

Yes, it’s possible to ride an electric bike without a battery, but its electrical features, like pedal assist and throttle, won’t work. The electric bike will basically work like a traditional bike with all its mechanical components. 

The only difference you’ll feel between the electric bike without a battery and a traditional bike will be the weight. Since traditional bikes aren’t fitted with any electrical components, they are much lighter and easy to maneuver.

What does the battery mean for an electric bike?

The battery’s main job is to support and power the motor, which is the real star of an electric bike. However, the motor is essentially nothing without the battery.

The battery’s voltage decides how well the motor will perform, while its capacity decides how long the motor will assist the rider.

If you want the best electric bike experience, you should spend time researching what battery is right for how you want to use your ebike. It will essentially determine the overall riding experience, and investing in a high-quality bike will save you the worry of replacing or repairing it for a good 5-8 years.

The future of batteries for electric bikes

The future looks pretty exciting, with manufacturers readily investing in research to further technologically advance electric bikes. The goal is to overcome all the shortcomings we encounter today. 

Manufacturers are looking to increase the range and lifespan of batteries while finding better ways to integrate them into a bike. 

Ideally, the batteries will be lighter and less noticeable so that they don’t hinder the riding experience in any way.

Another goal is to improve the charging time so that riders can get back on the road without waiting long.

With the right technological advancement, the sustainability of electric bike batteries will increase and reduce the need for replacements.

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Matt standing next to his Xiaomi M365 Pro electric scooter and holding an electric scooter helmet
My name is Matt Trajkovski. I love electric scooters, and electric vehicles in general. I like doing a lot of testing, reviewing, and research on various electric scooter models and brands, looking for great value and performance, both through data and experience. All of the content published on this blog goes through a rigorous review and editorial process, and our product reviews not only include the hands-on experience of our own team members, but the experience of our audience members as well. My goal is to provide you with the best information about electric scooters possible. You can see all of my posts in my articles archive.

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