Can You Overcharge An Electric Bike Battery. Nimh ebike battery

Can You Overcharge An Electric Bike Battery?

E-bikes are becoming increasingly popular, as they provide a great way to get around without relying on fossil fuels. E-bikes popularity also grew to unprecedented levels during the COVID-19 pandemic.

With new technology comes new systems. Charging an electric bike battery is a key part of keeping your e-bike in good working order, so it’s important to know how to do it correctly.

What Is an Electric Bike Battery?

An electric bike battery is a rechargeable battery used to power an electric bicycle. It helps provide the pedal power needed to make the bike move. Electric bike batteries come in various sizes, shapes, and voltages, so you’ll need to choose the right one for your e-bike.

Types of Electric Bike Batteries

Electric bike batteries come in several types. Lead-acid, nickel-cadmium, nickel-metal hydride, and lithium-ion are the options at your disposal. Each type of battery has its advantages and disadvantages, so it’s pivotal to choose the right one for your needs.

Lead-Acid Electric Bike Batteries

Lead-acid electric bike batteries are among the most common batteries used in e-bikes. They are typically cheaper than lithium-ion batteries but also have some disadvantages. These include:

  • They are heavier than lithium-ion batteries.
  • They have a shorter lifespan than lithium-ion batteries.

Lithium-Ion Electric Bike Batteries

Lithium-ion electric bike batteries are a popular type of battery on the market. They have several advantages over lead-acid batteries, including:

  • They are lighter than lead-acid batteries.
  • They have a longer lifespan than lead-acid batteries.
  • They provide more power than lead-acid batteries.

Nickel-Cadmium Electric Bike Batteries

Nickel-cadmium electric bike batteries are another type of battery that is available. Some of the outstanding features of nickel-cadmium batteries include:

However, there are some disadvantages to using nickel-cadmium batteries, such as:

Nickel-Metal Hydride Electric Bike Batteries

Nickel-metal hydride electric bike batteries bear similarities to nickel-cadmium batteries but do not contain cadmium. As a result, they are less toxic, but because they contain nickel, they still need careful disposal.

Is It Possible to Overcharge an E-Bike Battery?

Now that we know a bit more about electric bike batteries, let’s answer the question: can you overcharge an electric bike battery?

The short answer is yes, it is possible to overcharge an electric bike battery. However, it is not often something that will happen if you accidentally leave your battery plugged in for too long.

Instead, overcharging most often occurs when there is a problem with the battery charger.

How Do You Overcharge an E-bike Battery?

Rechargeable batteries are designed to cycle off and on as they charge and discharge, which helps to protect the battery from overcharging.

When a battery overcharges, it receives too much voltage for too long, which can damage the battery.

There are several ways an electric bike battery can overcharge. These include:

  • Using a charger not designed for the battery
  • Using a charger with the wrong voltage
  • Leaving the battery plugged in for too long (less common due to the battery’s built-in protective measures)
  • Charging the battery in extreme temperatures

Can Overcharging Damage an E-bike Battery?

Regular overcharging of batteries can cause several problems.

Reduced Battery Capacity

Overcharging can reduce the capacity of your battery, meaning it will no longer be able to hold as much charge.

Why does this happen? When a battery overcharges, chemical reactions may occur inside it, breaking down some of the materials and reducing its capacity.

Increased Battery Temperature

Overcharging can also cause the battery to heat up. When a battery is overcharged, it produces more heat than it can dissipate, which causes the temperature to rise rapidly.

Although rare, fires have resulted from overheated e-bike batteries. As you can imagine, the damage can spread to more than just your battery. It may also damage the bike itself.


Sulfation is a process that occurs when lead-acid batteries overcharge, resulting in a build-up of lead sulfate on the plates inside the battery. In turn, the battery capacity reduces.

Decreased Battery Life

How is battery lifespan defined? Battery lifespan is the number of charge/discharge cycles a battery has. Overcharging a battery can shorten its lifespan by reducing the number of cycles it can go through.

A complete charge cycle occurs when a battery is charged from empty to full and discharges back to empty. When a battery overcharges, it goes through partial charge cycles, which can shorten its lifespan.

Caring for an Electric Bike Battery

It is imperative that you take care of your electric bike battery if you want it to last. There are a few simple things you can do to extend the life of your battery and keep it in good condition.


How you store your battery has an impact on its lifespan. You should always keep your battery in a cool, dry place.

Avoid storing it in direct sunlight or near any heat source. Heat can cause chemical reactions inside of your battery and damage it.

You should also avoid storing your battery in a completely discharged state. Make a habit of it, and the battery capacity will reduce.

If you need to store your battery for a long time, it is best to keep it at around 50% charge.

It is good to recharge the battery every few months to keep it in good condition.


It is essential to use the correct charger for your battery. Using a charger not designed for your battery can damage it. Make sure you always use the charger that came with your bike or one specifically designed for your battery.

It is also important to avoid overcharging your battery. As we have seen, this can damage the battery and reduce its lifespan.

Always follow the instructions that came with your charger and stop charging when the indicator light turns green.

When charging the battery, ensure it is done in a cool, dry place away from flammable materials. You should also avoid charging the battery in extreme temperatures as this can result in permanent damages.

How To Make E-Bike Battery Last Longer

There are several ways you can extend the life of your e-bike battery and keep it in good condition.

The Right Mode in the Right Moment

It is important to use the right mode when riding your bike. For example, if you only ride for a short distance, it is best to use the low or eco mode. These modes exist to help preserve the battery and make it last longer.

Riding in the Right Conditions

You should also try to avoid riding in extreme conditions, such as in very cold or hot weather. Extreemes can put a strain on the battery and reduce its lifespan.

Storing the Battery Properly

We’ve already talked about how important it is to store your battery properly. Remember: cool, dry, and halfway charged.

Regular Maintenance

It is also good to regularly maintain your electric bike and its battery. Clean the bike and check the tires. You should also check the battery regularly to ensure it is in good condition.

Do Not Overload Your Bike

You should also avoid overloading your bike. Too much weight will strain the battery and reduce its lifespan. If you need to carry a lot of weight, it is best to use a trailer or cargo rack.

Checking Battery Health

It is important to check the health of your battery regularly. Do so by checking the voltage with a multimeter. If the voltage is below 36V, it is time to replace the battery.

Frequently Asked Questions

Still have questions? We can help!

An electric bike battery’s lifespan depends on several factors, including how it is used and stored. With proper care, an electric bike battery can last several years. Store it in a cool, dry place, avoid extreme temperatures, and regularly clean the bike.

When in use, it is best to charge your electric bike battery every few months. If you are not using your bike regularly, it is still a good idea to charge the battery every few months to keep it in good condition. It is of utmost importance that the charge cycles are completed properly to avoid damaging the battery.

You’ll need to check the voltage with a multimeter. If the voltage is below 36V, it is time to replace the battery. Another way to tell if your battery is dead is if it will no longer hold a charge. If your battery can’t maintain its charge, you won’t be getting very far!

Your battery has a built-in charging system that will shut off when the battery is fully charged. Therefore, leaving your electric bike battery charging overnight is relatively safe, but if you can


Overcharging an electric bike battery is not recommended as it can shorten the battery’s lifespan. It is important to understand the proper way to charge your battery and how to care for it properly.

By following these tips, you can extend the life of your electric bike battery and keep it in good condition.

Jason Hawkley is a biking enthusiast, which is a nice way of saying he’s a total nerd when it comes to bikes. One day while mountain biking through the woods in New Hampshire, the idea came him to create Our Streets as a way to share his biking passion with you.

Everything you need to know about e-bike batteries [from a battery engineer]

Would you be the person taking the stairs or the escalator?

I’ll be honest. barring the one-off day that I’m feeling particularly sprightly, I would just hop on the escalator with those 30 people on the right. And I’m willing to guess that most of you would too.

What we can gauge from this picture is that most people would rather do as little work as possible to get from point A to point B. This is especially true when it comes to commuting on a bike. The picture above is analogous to the difference between a regular bike and an e-bike.

Even if we address all the concerns when it comes to biking in a city (like safe biking infrastructure), we can’t expect to change fundamental human behavior. when given the option between less work or more work to achieve the same outcome, people will more likely choose to do less work.

Since getting my e-bike, I can comfortably bike from my home in Somerville to the Seaport district in Boston. a roughly 5-mile trip. in just about 20-minutes. All of a sudden, biking 5-miles is a piece of cake. I also don’t have to spend time sitting in traffic, waiting for public transit, or worry about showing up to a meeting looking like I swam across the Charles river to get there.

The beauty of an e-bike is that it makes cycling an inclusive mode of transportation because it doesn’t discriminate by age or physical ability.

When it comes to purchasing an e-bike though, there are a plethora of options for both the bike and battery. So how do you decide which one is best for your needs? As a battery engineer who has built hundreds of batteries and logged way too many hours soldering battery packs, here are my thoughts on the most commonly asked questions when it comes to e-bike batteries.

If you’re new to battery terminology, you might want to start here: Battery terms that every e-bike owner should know.

In this post, we’ll cover the following questions:

What is the best e-bike battery?

This is one of the hardest questions to answer. There are so many variables that go into what makes a good battery and what’s best for you, may not be the best for me. Even then, a good battery can perform poorly if it’s not cared for properly.

Battery packs are made up of individual battery “cells”. Cells are classified into cylindrical cells (like your AA and AAA) and prismatic cells (like the one in your phone). Each class of battery is manufactured in a variety of form-factors (in the battery world we use this term to mean size). The most commonly used form-factor of cells in an e-bike battery pack is the 18650.

A battery pack is only as good as it’s weakest cell.

When it comes to batteries, in my experience, there is a strong correlation between price and quality. I don’t follow this rule when it comes to most things like for example, box wine (I’m just saying, there are plenty of really good box wine options these days!). When it comes to batteries though, you really don’t want to be compromising on quality because you’ll eventually end up having to pay the price.

Here are some things to keep in mind when purchasing an e-bike:

Cell Manufacturers: Panasonic, LG, and Samsung have a good reputation in the battery industry for their high quality cells, so paying a premium for these cells is certainly worth it. If the e-bike you’re trying to buy doesn’t have or provide cell manufacturer information, they’re likely not going to be a reliable source anyway.

Cell Chemistry: Lithium-ion (li-ion) batteries are the best option for e-bikes. Although lead-acid batteries are significantly cheaper, they’re three times as heavy as their li-ion equivalents.

Li-ion has several variants of cell chemistry. The most popular ones for e-bikes are Nickel Manganese Cobalt (NMC), Lithium Cobalt Oxide (LCO), and Lithium Iron Phosphate (LFP). The metrics to look for when selecting a cell chemistry are:

  • Specific Energy: has an impact on the range of your battery.
  • Specific Power: how the battery handles high load scenarios like going up
  • a hill.
  • Safety: does the chemistry have a history of high in-field failures.

There are trade-offs when choosing one chemistry over another, but as we’ve shown in the image below, NMC and LFP are both great options that both offer the best value in terms of performance, price, and safety.

Picking the right battery chemistry has to do with figuring out what matters most to you. Do you want a battery that has a longer range (higher specific energy) but doesn’t have as much power? Or do you want a battery that has a more power (higher specific power) but may not last as long?

In my opinion, the best e-bike batteries are likely going to be made from cells manufactured by Panasonic, LG, or Samsung with either LFP or NMC cell chemistry.

What is the range of an e-bike battery?

The range of a battery pack depends on the amount of energy packed inside of it and is measured in Watt-Hours (Wh). Watt?

Watt-hours are calculated by multiplying the battery capacity, in Amp-hours, by the battery Voltage, in Volts.

Let’s assume that, on average, 1-mile requires about 25Wh of energy. So a 14Ah, 36V battery should get you about 25-miles per charge.

Keep in mind that the weight of the rider, outside temperature conditions, and the amount of pedaling will make a significant difference in range.

A word of caution: the range that e-bike manufacturers provide should be taken with a grain of salt. That number is generated from tests that are run in perfectly tailored lab conditions. Do you charge any of your electronics in an incubation chamber set at 28° C with a lab-grade charger that applies the perfect current while charging? Yeah, I don’t either. And so, We should assume that the manufacture-specified range is delivered only if the battery is charged and discharged under ideal conditions i.e. not real world conditions.

For a more realistic estimate, shave off 15% of the manufacturer specified range and assume this padded number to be your real range.

If you’re looking for a longer range, choose a battery that has higher capacity (Ah). If you’re looking for more power, choose a battery that has higher voltage (V). Learn more why voltage and capacity matter.

What is the lifespan of an e-bike battery?

There are several factors that affect the lifetime of a battery such as:

  • environmental conditions: temperature during charging discharging
  • charging rate: how fast or slow your battery is charged
  • charging voltage: what voltage the battery is charged to
  • depth of discharge (DoD): what voltage the battery is discharged to

The list above isn’t exhaustive but, in general, batteries decay as a function of time in the charged state. Period.

Day 1: You get your new e-bike and charge it up to 100% and go on a bike ride. When you come home, you charge the bike back up to 100% and you’re excited to ride it again soon.

Day 2. 364: Life get’s in the way and you still haven’t been out on your bike since that first ride.

Day 365: One year later, it’s the perfect day for a bike ride and you finally have some time on your hands. You head to your basement, unlock your bike, and excitedly turn it on. 80% charge. What? You clearly remember charging your bike to 100% last year before moving it to the basement!

The truth is, we can’t beat thermodynamics. I’ll say it again: batteries decay as a function of time in the charged state.

Now, because you left your battery at 100% for a whole year in a basement with no temperature control, you inadvertently caused your battery to lose a certain amount of irreversible capacity. Your range will be ~20% lower and you’ll likely have to replace your battery sooner than you expected. The table below shows you how much recoverable capacity exists in a battery after storing it at different temperatures and different charge states for 1-year.

This is why a lot of electronics come with batteries that are only partially charged. to help slow down this decay. That being said, it’s hard to track how long e-bikes and their batteries have been sitting in warehouses before being delivered to your door so you could get a battery that has been decaying for a year or two.

Manufacturers also tend to overrate their batteries and will make claims about certain batteries having a lifetime of at least 1,000 cycles.

The lifetime of a lithium-ion battery is described as the number of cycles until the capacity (Ah) drops below 80% of it’s initial capacity. In general, this is roughly 250-400 cycles (depending on battery chemistry and other factors) which amounts to roughly 1.5 to 2 years if you charge discharge daily and care for your battery properly.

How to charge your e-bike battery to make it last longer

  • The thing that will kill your battery faster than anything else is leaving it charged at elevated temperatures. If it’s 80 degrees outside and you have your e-bike fully charged, move it indoors where it’s cooler and try to drain the battery as soon as possible.
  • Charge your battery at room temperature as often as possible.
  • When sourcing an e-bike battery charger, the slower the charge rate the better. For example, if you have a 2-Amp charger, and your battery is a 14 Ah battery pack, you are charging at 14 Ah / 2-Amps = 7-hours. This is a nice, slow charge which will certainly improve the longevity of your battery pack. Avoid charging at rates that are faster than 2-hours for a full charge.

There’s a lot that goes into choosing the best battery for you e-bike, and there certainly isn’t a one-size-fits-all approach. But if I were buying an e-bike battery today, here’s what I’d do: LFP or NMC, slow charge, avoid storing or charging in hotter temperatures, and leave the battery at around 30% charge if you don’t plan on using it for a while.

Have questions? We’d love to help. You can get in touch using the contact form or find us on @somerville_ev

Also, subscribe below for alerts on our next post to learn more about batteries!

How Long Do Ebike Batteries Last How to Increase Lifespan

E-bike batteries can be very expensive, so much so that they actually make up the vehicles largest cost. E-bike owners have to ensure that their batteries are in top shape and have the longest possible lifespan.

How long will your e-bike battery last? Most batteries that fall in this category can last from 3 to 5 years until start losing some of their efficiency. But with proper care, it’s possible to completely maximize your battery life’s full potential.

So how exactly do you keep your battery healthy? In our article, you will learn more about your e-bike battery life and the best ways you can prolong its life, from proper maintenance and usage to buying the best charger for your unit.

  • Types of batteries
  • Lead-acid (SLA)
  • Lithium-ion (Li-ion)
  • Lithium Cobalt (LCO)
  • Lithium Manganese (LiMg204)
  • Lithium-ion Polymer (Li-pol)
  • Nickel-cadmium (NiCd)
  • Nickel-metal Hydride (NiMh)
  • Buy Both a Fast and Slow Charger
  • Buy a Slow Charger Only
  • Buy a Fast Charger Only
  • Use the Finger Test
  • Buy a Charger with Advanced Variable Amperage
  • Never charge your battery to its full capacity
  • Don’t Keep Your Battery in Hot Temperatures
  • Avoid Going at Prolonged High Speeds
  • Safely Storing Your Battery for Longer Periods
  • Speed
  • Accelerating and Steep Terrain
  • Maximum Battery Capacity
  • Motor Efficiency
  • Tire Pressure
  • Pedalling
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Types of batteries

You need to learn what kind of battery your unit has first before anything else. Here are the standard battery types used for e-bikes and their specifications.

Lead-acid (SLA)

Lead-acid batteries are the cheapest ones you’ll find in the market. Unfortunately, it comes with a few drawbacks. They are particularly sensitive to bad treatment, they weight considerably more than lithium and nickel batteries, and they have a shorter lifespan compared them as well. This isn’t a good choice if you’re going to use your e-bike regularly.

Lithium-ion (Li-ion)

Lithium-ions are the most commonly seen batteries for the e-bike (over 90% of the whole market.) In general, they generate more power considering their weight and have longer lives. For these very reasons, they are also on the more expensive side as well.

Lithium Cobalt (LCO)

Lithium-ion batteries have a few subcategories, each with their own unique features. Lithium cobalt batteries, for instance, are relatively new in the market, boasting a considerably higher energy density compared to its brothers. Because of this, they can provide optimal power for far less weight.

Lithium Manganese (LiMg204)

Another new battery type of lithium-ion, its manufacturers claim that their product generates more power and has a longer life compared to other lithium types. This battery is also used in hybrid cars such as the Nissan Leaf.

Lithium-ion Polymer (Li-pol)

The lithium-ion polymer battery doesn’t offer anything different from the original lithium-ion in terms of price, weight, or range. However, it offers a few unique key features. Unlike its predecessor, these batteries have no liquid components, so it has no need for heavy and bulky protective cases. It also means that it is also less prone to being damaged through misuse and is generally more stable.

Nickel-cadmium (NiCd)

Nickel batteries are becoming more and more of a rarity because of the negative environmental impact that they pose. They are very difficult to recycle and is considered a toxic pollutant. While they do have more capacity compared to lead-acid batteries, you’re better off choosing a lithium-ion model.

Nickel-metal Hydride (NiMh)

These batteries are a touch more efficient than its predecessor, but they also cost more. They also tend to last longer and are easier to recycle, but lithium-ion batteries are still considered better.

Electric Bike Charging Times: Fast or Slow?

Many e-bike owners make the mistake of only having a fast battery charger, and while these do save you plenty of time, they come with heavy drawbacks.

Apart from their more expensive price tag, fast e-bike chargers also come with it, a potential hazard. Because of the large surge of electricity that passes through it in a short amount of time, these chargers often require a heat sink to keep cool.

You would be hard-pressed to find chargers of this type above 5-amps for this very reason. Charging a battery too fast will shorten its lifespan, and they become potential fire hazards as well.

If you’re a new e-bike owner, we recommend that you use a slow charger that is healthier and safer for your battery.

What Is BMS Charging And Why Is It Important?

Battery Management System or BMS is a form of protection for your battery pack. It limits the speed in which your pack can charge. For instance, if you plug in a battery with 10-Ah in a charger that’s 5-amps, this battery will not charge because of the BMS. Most BMS’s for lithium batteries have a limit of 7 amps, any higher and the battery will not charge.

Another function of the BMS is that it balances the charging of your batteries cells where they get equal amounts of energy. This maximizes your batteries life and makes charging safer. Balance charging is relatively slow, though. Advanced BMS systems need ample time to balance every cell in your battery.

Bigger Batteries Are Generally Better

The larger your battery is, the more is healthy and safe to charge it at much higher amps. For instance, charging a 10 Amp-hr battery with 5 amps is considered fast, but not for charging a 20 amp-hr battery.

If you charge your battery quickly too often, it will severely affect the life expectancy of your battery’s life. We recommend a slow charger that takes up to more than four hours of charging time. Or if you want something just a little bit quicker, you can opt to buy a charger that can switch between slow and fast charges to maintain a healthy temperature.

If your e-bike has a battery pack with high-amp cells and has the capacity for high discharges, they can generally afford faster charging without affecting their life-expectancy considerably. Some drawback of these types of battery pack is that they have a lower energy density and are more expensive compared to other packs with lower-amp cells.

What Kind Of Charger Should I Buy?

Before you consider the right charger for you, (as explained above) we recommend that you buy the biggest battery your bike can accommodate that features high-quality cells. Here are some of the recommended options you can opt to choose depending on your needs and preferences:

Buy Both a Fast and Slow Charger

This way, you can choose a charger to suit your circumstances. If you’re hard-pressed for time, you can use a fast charger to speed up the charging process. Any other time, you can use a slow charger to keep your battery pack healthy. While buying two can be more expensive, they can be a good investment if you have a need for it.

Buy a Slow Charger Only

This is by far the safest bet and usually the cheapest as well. If you can afford the longer charging times, a slow charger can prolong your batteries life.

overcharge, electric, bike, battery, nimh, ebike

Buy a Fast Charger Only

Granted, this will cause your battery pack to lose a few cycles of its life, but it will still give you plenty of use and survive an ample amount of years. By then, you would want to replace your battery pack for a lighter and more efficient model.

If you opt for this option, buying a bigger battery pack will solve all the drawbacks that using a fast charger pose because they can take more energy and withstand the much higher temperatures that come with fast charging.

Use the Finger Test

A good tip of telling if your battery is charging too fast is feeling it with your finger while it’s charging. If it feels fairly warm, this most like means that you’re battery cant handle a fast charger (without sacrificing some of its lifespan.)

Buy a Charger with Advanced Variable Amperage

Instead of buying two separate chargers, you could buy a charger that offers both features in a single unit. These types of charges have a slow and fast setting so you can change the type of charging you want depending on your needs. This also reduces a bit of the wiring clutter when having multiple chargers.

How To Charge Your E-bike Efficiently

As an e-bike owner, you want your vehicle to perform well in a variety of different situations, whether you’re riding in a park during a leisurely afternoon weekend, or riding fast to avoid the heavy traffic for your morning commutes.

In order to keep your e-bike in top shape, every one of its systems needs to work well. One of the biggest key components of your e-bike is its battery. You want your battery pack healthy and in prime condition, and to do so, you can use some of these handy tips that will prolong your battery’s life and keep its efficiency at 100%:

New e-bike batteries have to be charged for half a day

After you buy a new electric bike, you should take the time when charging it for the first time. Charge for up to 12 hours in order to ensure that the currents are flowing through every cell and to condition your battery pack properly.

Charge your e-bike battery regularly

E-bikes using lithium battery packs, or most e-bikes for that matter, generally last much longer if you regularly use them, and by extension, regularly charging them.

Whenever you discharge the battery of your e-bike, you don’t for it to go all the way completely. Instead, try to charge your battery within the range of 30% and 60% of its remaining capacity to maximize its life expectancy.

A few experts recommend a full discharge every once in a while (when you reach from 30 to 40 charges, for instance.) Otherwise, try to follow the 30% and 60% guideline.Make it a habit of riding your e-bike regularly so you can also charge its battery pack every so often.

Avoid charging in extreme temperatures.

Much like their riders, electric bikes prefer moderate temperatures over anything else. If you want to extend your battery pack’s lifespan, avoid using and charging them in extreme temperatures.

When your battery pack is in a charging cycle, the environment should not reach 110F or freezing temperatures. Try to stay between the temperature range of 60 to 70 for the optimal charging temperature.

Don’t Overcharge an Electric Bike Battery

Never leave the battery pack of your e-bike on its charger for very long periods (i.e. a few days or even more.)If you do so, the battery will discharge and leave itself most likely at 95% of its capacity. The charger then proceeds to do its job and top off your battery. This whole cycle of topping off and minor discharging will create series after series of bad charging cycles.

You can use a timer (on your phone, for example) to remind yourself when to take your battery of its charger at the right moment.

Don’t Store an Empty Battery

There are moments when you might have to put your e-bike battery in the storage. For example, when you’re going on a trip, or maybe the temperature outside is too low for riding. Either way, never store your battery in an empty state and try to keep it between 40% to 70% of its full capacity.

How To Take Care Of Your E-bike Battery

Never charge your battery to its full capacity

One of the best ways to prolong the lifespan of your battery is to stop charging it up to 100%. Lithium-ion battery packs will often come shipped with 50% to 60% of their charge capacity. These are safe percent ranges to store your battery.The only time you need to charge your battery up to 100% is the moment you first receive it.

Charging it to its full capacity will ensure that each one of its cells is fully balanced.Every succeeding charge should not reach 100%. Most e-bikes use lithium-ion battery packs, and these batteries prefer being less than their full capacity. You should only charge them up to 80% then it off from the charge.

It’s also recommended that you don’t discharge them down to less than 20%. To summarize, keep your battery charge in between 20% to 80% charge capacity.

You might be wondering why should only use 60% of the total capacity of your battery. To put it simply, this serves to prolong your battery’s life and reduce the costs of having to buy new batteries more often.You might be worried that 60% is not enough to complete longer trips without stopping to recharge. This can easily be remedied by buying a higher capacity battery.

If you’re going to use your bike regularly for longer distances, you can calculate what kind of battery you need to fit your usage. For instance, if you have a 12Ah battery when at 48V, you have 624Wh for your whole battery (48V13Ah=624Wh). If you’re going to use 60% of that, then its only 374Wh.

Let’s say that you’re going on 1km/20Wh. This means that your battery can cover 19km before it needs to be charged.It’s also best to consider if you’re going on a roundtrip without charging or can you charge your battery at each end.

Don’t Keep Your Battery in Hot Temperatures

We’ve told you previously that your battery shouldn’t be charged in extreme temperatures. This holds true when you’re storing it as well. Especially for a fully charged battery pack, keeping at in hot temperatures can significantly lower its life expectancy. If you’ve already read the first step, you know not to charge you battery to its maximum capacity.

Find a cool and dry spot where you can store your battery safely after you’re done charging it. Never leave it under direct sunlight or in the warmer portions of your house. Try to find a place that is open with good ventilation. Closed spaces, while might be initially cool, could heat up eventually in hot weather.

Take some extra precautions if you reside in a hot and humid area because this kind of environment isn’t good for your battery pack’s health.

Know that riding your e-bike in very hot or cold temperatures will also negatively affect your battery’s performance. There are, of course, times when this is unavoidable, but it’s good to keep in mind.

Avoid Going at Prolonged High Speeds

If you want to keep your battery at its maximum efficiency, we advise that you shouldn’t strain your e-bike too much, because its motor will use up higher amounts of energy within a shorter period of time. Avoid running your e-bike at full speed for longer periods because this will discharge your battery too fast.

At this rate, you’ll have to charge your battery pack above the optimal charging frequency. Constantly charging and discharging your battery isn’t good for its health, especially if it’s fully charged or completely discharged. It’s good to regularly use your e-bike and charge it’s battery regularly, but it’s ill-advised to constantly run it at full speeds because, over time, your battery will hold much less charge than it originally did.

Compared to riders who ride their e-bike at a steady pace, the battery lifespan of a rider who goes at maximum speed will be considerably shorter.

Safely Storing Your Battery for Longer Periods

If you’re wondering if it’s safe to store a battery for months without use, generally speaking, usually fine. Read the user manual of your battery to check if it can be stored for longer periods because recommendations can vary depending on battery types.

Remember, as we’ve stated before, keep your battery charged within the safe range when you’re storing it for the long run. If they’re not within that range while in storage, this will cause stress on the batteries cells and cause the whole unit to age much quicker. The energy stored within your batteries will also escape gradually or self-discharge. It’s best to charge it every so often to keep it within the good range.

Also, remember the optimum temperature range of storing batteries (between 59F to 68F), because the more it strays from that range, the higher the change of your battery degrading. Keep it away from humid or damp areas, because it can be very dangerous if moisture seeps into your battery pack.

Maximizing Riding Range

One of the most important aspects you want for an e-bike battery pack is its riding range. Range refers to the distance that your battery can let you travel on one charge, and this is affected by many factors:


Air resistance will increase at a rate of the cube of speed. In common terms, this essentially means that accelerating will cause resistance to rise exponentially. Unless your hard-pressed for time and you need to go quickly, we recommend that you travel around 15mph for the optimal speed.

Accelerating and Steep Terrain

Using an e-bike in hilly areas such as San Francisco will use up much more energy when climbing to higher areas, while in flatter areas like the Netherlands, they tend to consume less energy. Accelerating your vehicle also puts relatively the same strain as riding to steeper terrains. This uses up much more energy, and it will deplete your battery’s reserves faster.

Maximum Battery Capacity

Usually, the bigger the battery pack you have, the higher its maximum capacity. It goes without saying that higher capacities will enable you to travel longer distances.

Motor Efficiency

A high-quality motor will convert energy into the maximum amount of forwarding power it can produce. When buying a new or used e-bike be sure to take into account what kind of motor it uses.

Tire Pressure

Much like other vehicles, having an e-bike with low tire pressure will affect your driving range. If you have low tire pressure, your battery will have to work harder in order to compensate for the less than optimal condition of your tires. This will drain your battery faster and give you less travel distance.


It’s only logical that whenever you’re not engaging your battery, the more distance you can travel using it. Only giving yourself a boost whenever necessary will ensure that you can travel the maximum distance your battery can reach. You can do this when you’re traveling on less tough terrain like downhills or flats.


Replacing the battery pack for your e-bike is a very expensive undertaking. By following our guide, you can keep your battery in top shape for many years to come and prolong its life span. In the long run, proper maintenance and care will save you a lot of money for little to no effort.

I always had a thing for cycling sports and love almost anything that involves bikes and boards. I work part-time as a designer in the tech industry and work on my blogs whenever I can.

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Posted on Last updated: December 21, 2022

Battery calculator for any kind of battery : lithium, Alkaline, LiPo, Li-ION, Nimh or Lead batteries

Enter your own configuration’s values in the white boxes, results are displayed in the green boxes.

Principle and definitions

Capacity and energy of a battery or storage system

The capacity of a battery or accumulator is the amount of energy stored according to specific temperature, charge and discharge current value and time of charge or discharge.

Even if there is various technologies of batteries the principle of calculation of power, capacity, current and charge and disharge time (according to C-rate) is the same for any kind of battery like lithium, LiPo, Nimh or Lead accumulators.

Configuration of batteries in series and in parallel : calculate global energy stored (capacity) according to voltage and AH value of each cell

To get the voltage of batteries in series you have to sum the voltage of each cell in the serie.

To get the current in output of several batteries in parallel you have to sum the current of each branch.

Caution : do not confuse Ah and A, Ampere (A) is the unit for current, Ampere-hour (Ah) is a unit of energy or capacity, like Wh (Watt-hour) or kWh or joules.

The global capacity in Wh is the same for 2 batteries in serie or two batteries in parallel but when we speak in Ah or mAh it could be confusing.

Example :. 2 batteries of 1000 mAh,1.5 V in series will have a global voltage of 3V and a current of 1000 mA if they are discharged in one hour. Capacity in Ampere-hour of the system will be 1000 mAh (in a 3 V system). In Wh it will give 3V1A = 3 Wh. 2 batteries of 1000 mAh,1.5 V in parallel will have a global voltage of 1.5V and a current of 2000 mA if they are discharged in one hour. Capacity in Ampere-hour of the system will be 2000 mAH (in a 1.5 V system). In Wh it will give 1.5V2A = 3 Wh

That is why it is better to speak in Wh (Watt-hour) rather than Ah (ampere hour) when you speak of capacity of a pack of batteries with elements in series and parallel, because capacity in Watt-hour is not linked to the voltage of the system whereas capacity in Ampere-hour is linked to the voltage of the pack of batteries.

Rating capacity and C-rate

C-rate is used to scale the charge and discharge current of a battery. For a given capacity, C-rate is a measure that indicate at what current a battery is charged and discharged to reach its defined capacity. A 1C (or C/1) charge loads a battery that is rated at, say, 1000 Ah at 1000 A during one hour, so at the end of the hour the battery reach a capacity of 1000 Ah; a 1C (or C/1) discharge drains the battery at that same rate. A 0.5C or (C/2) charge loads a battery that is rated at, say, 1000 Ah at 500 A so it takes two hours to charge the battery at the rating capacity of 1000 Ah; A 2C charge loads a battery that is rated at, say, 1000 Ah at 2000 A, so it takes theoretically 30 minutes to charge the battery at the rating capacity of 1000 Ah; The Ah rating is normally marked on the battery.

Last example, a lead acid battery with a C10 (or C/10) rated capacity of 3000 Ah should be charge or discharge in 10 hours with a current charge or discharge of 300 A.

Why is it important to know the C-rate or C-rating of a battery

C-rate is an important data for a battery because for most of batteries the energy stored or available depends on the speed of the charge or discharge current. Generally, for a given capacity you will have less energy if you discharge in one hour than if you discharge in 20 hours, reversely you will store less energy in a battery with a current charge of 100 A during 1 h than with a current charge of 10 A during 10 h.

Formula to calculate Current available in output of the battery system

How to calculate output current, power and energy of a battery according to C-rate? The simplest formula is :

I = Cr Er or Cr = I / Er Where Er = rated energy stored in Ah (rated capacity of the battery given by the manufacturer) I = current of charge or discharge in Amperes (A) Cr = C-rate of the battery Equation to get the time of charge or charge or discharge “t” according to current and rated capacity is : t = Er / I t = time, duration of charge or discharge (runtime) in hours Relationship between Cr and t : Cr = 1/t t = 1/Cr

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