eBike Batteries Explained
There is a wide assortment of different batteries used on eBikes. eBike Batteries come in various styles, shapes, and sizes. We will discuss here the most common ebike batteries found in the industry, how they work, and what actually is inside an electric bike battery pack.
The most predominant style of battery in the ebike market these days is the large case battery. It is what we have on the Tower electric cruiser bike. These types of batteries are usually an internal frame battery, meaning they slide in or are within the frame of the bike. On many ebikes there is the internal frame pack that would go into a proprietary frame designed bike. Due to proprietary concerns and the dynamic nature of the electric bike industry why we do not recommend buying an ebike with this styled battery pack.
eBike Battery Industry Standards
All these battery packs have a commonality of having individual cells inside them. The current industry standard for the dimensions of these batteries is 18 x 6.50 inches. Each ebike battery has a circuit board inside which is called the battery management system which keeps all the individual cell packs at the same charge level, and also handles the charging and discharging of the battery pack.
There are a lot of different ebike battery manufacturers. The best batteries usually come from very reputable companies like Samsung, Panasonic, Bosch, or LG. We caution people when purchasing inexpensive batteries, as they are most likely Chinese knockoffs. These knockoffs will not perform nearly as well compared to trusted and reputable batteries who have quality control manufacturing systems and a trusted brand name. It’s important to remember you are buying from the brand that made the bike, not the battery. When ebike shopping make sure the battery on whatever ebike you choose to purchase is a reputable brand. Don’t settle for anything less. when an ebike company does not provide the name fo the cells in their battery, you can assume there battery is non branded and are generally sourced for low cost, meaning low quality.
Battery Performance Explained
As for the performance of an ebike battery, it is quantified by its storage capacity of each individual cell and the maximum discharge of the cell. The storage capacity translates into the range that you can use the bike. The maximum discharge will translate into the power in can deliver to the wheel. The battery capacity is measured in either Amp hours (Ah) or Watt hours (Wh).
It’s a good idea to look for an ebike that can give you a good range with good power, and ideally with a reputable battery brand as well.
The industry standard continues to improve, but generally any bike with a 500 watt motor and a 48v battery is considered good and more than satisfactory.
Additionally, you must also know that the range and power correlate with one another. The range will vary depending also on how much power level or pedal assist you will be riding on. If you travel on a low level of pedal assist, you can have a good range even on a small sized battery. And likewise, if you require a higher level of pedal assist, it might be best to opt for a battery with a higher range capacity.
If you’re interested in learning more about electric bikes check out our article on how an electric bike works from start to finish.
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. Show.me.the.data.
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!
Can’t decide between a fixed or a detachable ebike battery? We’ve got you
Cate Lawrence is an Australian tech journo living in Berlin. She focuses on all things mobility: ebikes, autonomous vehicles, VTOL, Smart ci (show all) Cate Lawrence is an Australian tech journo living in Berlin. She focuses on all things mobility: ebikes, autonomous vehicles, VTOL, Smart cities, and the future of alternative energy sources like electric batteries, solar, and hydrogen.
So you want to buy an electric bike. You’re confronted with an eye-wateringly large market and are not really sure whether to go for a bike with a detachable/swappable battery or with one that’s fixed permanently to the bike?
Don’t worry, folks, we’ve got you.
The case for a fixed battery
Tickets are officially sold out
But there might be some last-minute spots available
Ebike manufacturers speak:
Our bikes are built for the purpose of daily urban commuting and we feel that an integrated battery is favored. This has enabled us to build one of the lightest and most efficient urban commuting ebikes in the world that are fun and safe to ride. Our customers value the benefits such as lightweight, reliability, and the look of a regular bicycle.
We also understand that our bikes don’t fit everyone’s needs, but we have also seen many customers overcoming the charging block by charging their bike at work, for example. Also, as the range of the battery is more than enough for daily rides, you might only need to charge the bike only once or twice a week.
— Ardo Kaurit, CEO Co-founder of Ampler Bikes.
For the Delta ebike, we choose a non-removable battery because we want to make our e-bikes as light as possible. Removable batteries are generally bulkier and heavier, and also the frame needs extra reinforcements and parts like a lock and connector which make it heavier.
From a design perspective, the non-removable batteries are also easier to integrate in a way that is (almost) invisible to the user.
–Tom Schiller, co-founder and CEO of Mokumono.
The case for a detachable/swappable battery
Ebike manufacturers speak:
At Dance, our goal is to make it easier to choose an ebike over other travel every single time. One of the ways we can incentivize ebike usage is by designing products to fit our customers’ lifestyle; we want the customer to charge however is best for them.
That’s why we chose a removable battery: we want our customers to be able to easily charge their ebikes; not everyone has the ability to park near an outlet inside.
Though the Dance One is lighter than other ebikes, some may live on the third floor of an apartment building, for example.
With more than one battery you can recharge your bike in seconds. It’s a huge advantage for the customer.
I would say that eventually all micromobility vehicles will have removable/swappable batteries.
— JT Burke, head of hardware, Dance
Rad Power Bikes
At Rad Power Bikes, we believe in practical and accessible ebikes built for everything and everyone. Our bikes are designed intentionally for ease of use and maximum functionality. The choice of a semi-integrated battery was rooted in that design philosophy. It offers a streamlined look while celebrating that it is an ebike and maintaining ease of access and maintenance that our customers love about our bikes.
This design means the battery can be charged on or off the bike and that our riders can bring along additional batteries that can be swapped out for longer rides making our bikes a great option no matter where your destination lies.
— Arno Saladin, European Business Director, Rad Power Bikes
The elephant in the room is weather
Before you choose your choice of ebike, consider the climate or where you ride. One of the biggest factors in battery health is protecting your battery against the weather. Some general tips:
Temperatures below 5-10 degrees Celsius (40-50 degrees Fahrenheit) affect the battery’s performance. It’s advisable to bring your battery inside whenever practical. It’s also not advisable to charge the battery in areas where the temperature is below freezing.
Conversely, warmer temperatures can wear down the components that are used to generate power for your ebike, effectively leading to premature capacity loss. Storing your battery/bike in the shade in hot weather is a good idea.
Rad Power Bikes suggests you should always charge in a safe area that is dry, indoors, between 50 °F–77 °F (10 °C–25 °C), and away from direct sunlight, dirt, or debris. Logistics matter: Arrange the bike, battery, and charger to eliminate the potential for trip hazards, damage to the bike, battery, or charger.
Boxer Cycles advise that while most ebikes are water-resistant they shouldn’t be submerged in water, outdoors during heavy showers, or ridden through ridden deep puddles.
Store your bike out of the rain and make sure the battery is kept dry as much as possible.
Whatever you choose, an ebike is a long-term investment. You want a bike that can continue to serve you as battery innovation accelerates over time. And, yep, the next generation of batteries will be even better.
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Review: Triangle Frame Battery Bag by Electric Rider
I’ve always been a fan of doing your own electric bicycle conversion instead of buying a retail ebike. By going the do-it-yourself (DIY) route, you have so much more freedom and room for customization, allowing you to choose from many different ebike parts.
Nearly every electric bicycle part has been designed to seamlessly integrate with standard bicycles to make the conversion process simple and easy. Throttles just slip over handlebar ends, motors mount easily in the wheel dropouts, and controllers can be bolted just about anywhere. The only problem can be fitting a battery onto a bicycle.
There are a few ebike batteries specifically built for mounting to bicycle frames, but generally DIY builders have been stuck building their own custom boxes and enclosures.
The best place to mount batteries on an ebike is in the center triangle of a bicycle frame. By mounting batteries in the triangle, you keep the weight centered in the bike and lower to the ground. But how can you securely mount your batteries in such an odd shaped area of the bike?
Enter: The Electric Rider Triangle Battery Bag!
Electric Rider Triangle Battery Bag
I got my hands on one of these new bags about 6 weeks ago and have been putting it through the paces ever since.
Now this isn’t my first triangle bag I’ve used for mounting batteries on an ebike. Readers of EbikeSchool.com might remember a review I did of the Ibera triangle bag, which I loved. Well, now I’ve found the Ibera bag’s big brother, and that’s the Electric Rider triangle bag.
This triangle bag has everything I loved about the Ibera bag, and a whole lot more!
Let’s start with the material. The exterior of the bag is made from what appears to be some type of tightly woven nylon, which gives the bag its water resistant feature. The zipper itself is a waterproof variety, just like I have on many of my hiking bags that are meant to keep all your gear dry in a downpour. The zipper closes behind a plastic-like sealing barrier which stops water ingress via the zipper. These two methods together make the bag highly water-resistant. I hesitate to say it is water proof, because I’m sure if you held a hose to it for long enough, especially around the wire ports, you’d start to get some water leakage. But fortunately for us, real rain isn’t directed like a sideways hose, and the light sprinkling rain I encountered left me with a bone dry interior. I haven’t had an heavy rains yet to give it a more intense test.
The wire ports themselves are really neat. One port in the front is covered by a nylon hood, which means the wires exit up but then immediately turn 90 degrees to the side. This helps to keep falling water from entering the exit port.
Many people will require a top mounted wire exit, especially if the controller is to be included in the bag, because that’s the most direct path to the handlebars and all of the devices you’ll have mounted there. This hooded exit port is a great way to provide a top mounted exit port without the risk of water easily getting through.
The second wire port is located on the underside of the bag and is similar to the headphone ports on many backpacks. A spiral cut piece of rubber holds the port closed and tightly seals around wires that exit the port. These two different designs for top and bottom mounted wire ports should provide many options for accessing your battery and any other electronics stored in the bag.
This might be a good chance to check back in on the Ibera triangle bag I used before I got the Electric Rider triangle bag. While it was nice and roomy, it didn’t have any wire ports, probably because it was never meant for use on electric bicycles. That’s one of the biggest advantages of the Electric Rider triangle bag: it’s designed specifically for ebike use.
A great example of how this triangle bag is meant for ebikes is that included padding. The bag itself doesn’t feature built in padding, rather there is a long strip of foam padding included with the bag to allow the user to shape it to whatever battery they are using. At first I wasn’t a fan of this method, as I would have preferred a bag that came padded on all sides. But as I started using the bag, I realized how useful this feature was. By not padding the entirety of the bag, Electric Rider left as much usable space as possible in the bag. I could then add their padding only where I needed it. This meant the bag could remain as wide as possible for holding as thick a battery as you can get in there. Then you can just wrap the padding around the corners or bottom of the battery (or top of the battery if you want to put more stuff in there on top of it) as you see fit.
One downside of the triangle bag is that there isn’t a great way to protect against theft. This is a problem inherent in all battery bags, since they don’t lock to the bike the way an aluminum case battery can. One trick to get around this is to use a luggage lock on the two zipper pulls. This isn’t going to stop a determined thief, but it will prevent opportunistic crime where a would-be thief sees and easy target and goes rummaging through your battery bag. Check out my article on Ebike theft prevention to learn more here.
Adding a lock to the zippers is something you very well may want to consider, especially when you see how much expensive lithium you can cram into this bag. In terms of size, I’m not sure how else to say it other than that this bag is cavernous. It just keeps going. It will fill up the triangle on most bikes (and might even be too big for some, though it will squish down to fit) and its width means you can stuff a lot of battery into it.
The EM3EV triangle bag (which is a nice bag in its own right, and one which I will be reviewing here soon too) has been the largest triangle bag to date. Well, now we’ve got a new king in town, as the Electric Rider triangle bag is even bigger.
To test it out, I put it in the biggest, weirdest and most open frame I could find: the Electra Townie. This gigantic frame can fit enough lithium to take you half way across the country. The only problem is fitting it in there somehow. But the Electric Rider triangle bag actually surprised me by fitting in this gigantic frame triangle (or perhaps ‘abstract quadrilateral’ is more accurate than ‘triangle’). You can see that the frame is so large on this bike that the bag stretches a bit to fit. However, the long mounting straps that Electric Rider designed into the bag means that it can hold on securely even with the edges of the bag an inch or more from the frame members.
There is even still plenty of room for another bag up front to hold a controller, keys, wallet, sunglasses etc. The large shape of the bag and the extra long straps make this bag adaptable to many different size and shapes of bicycle frames. It even fit nicely in another weird yet smaller frame I had: a fat bike.
But fitting in a frame is just part of the story. A battery bag has to hold a lot of battery if it wants to live up to its name. So the next test involved loading the bag up with a bunch of batteries to see how well it worked.
For comparison, I tried loading in a few 48V 10AH lithium packs that I had on hand. Just for reference, my Ibera triangle bag could only hold one pack, and it had trouble closing. I was able to fit two of the 48V 10AH batteries into an EM3EV triangle bag, but the zipper wouldn’t close. Those same two packs fit in the Electric Rider triangle bag easily, and the bag was able to close with plenty of room for a controller and some other goodies.
I could even get three packs in the Electric Rider bag, but then I had trouble closing it.
Not for lack of trying though. A bit like battery Tetris.
An ebike bag that can carry 48V 20AH isn’t bad at all – that’s about twice as much battery as most retail ebikes feature. And remember, each of those packs I used had their own Battery Management System (BMS), wiring and connectors, not to mention cell arrangement designed for a single pack. If that had been one pack instead of three, and without all the redundant components, I think 48V30AH would have fit in the Electric Rider bag easily. It certainly swallowed my big 72V battery without a problem.
But all that space for batteries means the bag is going to get pretty heavy. Electric Rider was prepared for that though, and included nine (yes, nine!) wide velcro straps for holding the bag into the frame triangle. That sucker isn’t going anywhere.
So what does a bag like this cost? Well that’s the kicker – you’re going to have to shell out 65 to put one on your bike. Compared to the Ibera bag, that’s about 4 times the price, which might be hard to swallow for your first conversion. But when it comes to fitting the maximum amount of battery in your triangle, there aren’t many options out there that can do it besides Electric Rider’s triangle bag. And that’s when the price suddenly makes it seem so worth it. If you’re stuffing 20 AH or more of lithium in your bike’s frame triangle, you’re probably talking about a battery that is nearing 1,000 as it is. At that point, it just makes sense to protect that investment with a quality bag like this.
Want to get your own triangle bag? Head on over to Electric Rider’s website to check out their bag here.
Micah is a mechanical engineer, tinkerer and husband. He’s spent the better part of a decade working in the electric bicycle industry, and is the author of The Ultimate DIY Ebike Guide. Micah can usually be found riding his electric bicycles around Florida, Tel Aviv, and anywhere else his ebikes wind up.
Комментарии и мнения владельцев
They are about to release a new bag with more wire out locations and even a few with no logo. I now have 4 bags from 4 makers. The one is simply the best. And now with the wire out port at the lower corner for a mid drive, my near perfect bag. Get in line i preordered the unlabeled. but won’t give up the logo version. Now if someone would copy the Lunacycle zip tie version with a bag of this quality I d be near nirvana.
My Current Favorite Battery Source
My favorite source for batteries right now is Battery Hookup. They’ve also generously offered all of my readers a 5% discount if you use the discount code EBIKE.
This site is 100% free, so how do I support it?
All the help and knowledge I’ve provided here on EbikeSchool.com is 100% free If you want to support this site and help me keep it free, consider checking out my ebook and video course on building ebikes.
Ebikeschool.com has a lot of great info, but I’ve spent countless hours putting even more info, examples, how to’s, reviews, maintenance steps and buying guides into my book and video course. They are some of the most fact-dense and info-rich ebike resources available today. So check them out to see if they can help you with your own ebike!
If you want to learn more in-depth about building your own lithium battery, you’ll want to check out my book “DIY Lithium Batteries: How To Build Your Own Battery Packs” which is an Amazon #1 Bestseller in multiple categories! You can get it here on Amazon.
And if you don’t want to purchase my book (or you already have a lot of ebike knowledge), you can still support this site by simply clicking on this link before you shop on Aliexpress. Basically, that’s an affiliate link that shows Aliexpress that you came to them via my site. It doesn’t effect you at all, but if you make a purchase, this site will get a small percentage of the profit that Aliexpress makes. It’s a simple way to help support this site so I can pay the hosting and keep providing more free info (and to keep this site free of annoying ads). I have some of those affiliate links on a limited number of articles on my site. When I personally buy and test products that I find to be a combination of great quality and great prices, like these batteries, for example, I like to share them through those affiliate links. Again, it costs you nothing, but it allows me to keep cranking out more info and content for you guys!
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