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
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What You Need to Know About E-bike Battery Safety
It’s no secret that here at Liv we’re huge fans of electric bikes. Just the mere mention of our women’s E-bike range breaks us out in a big smile.
But. we’ll also put on our serious face and discuss electric bike battery safety with you. Because we know that E-bikes, with their high-tech batteries, can sometimes feel complex.
That’s why we’ve broken it down in this article. So read on to discover :
- What’s inside an electric bike battery (the techy stuff)
- How we ensure the highest battery safety standards on our Liv E-bikes
- The 13 must-know best practices for ultimate E-bike battery safety
The techy stuff: What’s inside an E-bike battery?
E-bike battery packs consist of individual battery cells containing lithium-ions. These battery cells store the energy to power the motor.
E-bike batteries are made with either cylindrical, prismatic, or pouch-shaped cells. The shape of these cells is really important. High-quality E-bike battery suppliers like Panasonic, Shimano, and Bosch use cylindrical cells because they handle higher temperatures without deforming.
Aside from the individual battery cells, a critical component inside an E-bike battery is the battery management system (BMS).
The BMS is hugely important as it regulates the individual performance of each battery cell. Regulation is important because even when they’re installed at the same time all the individual batteries don’t drain, deteriorate or perform at the same rate. Some cells last longer than others, some cells will drain slower than others and some will glitch out and cause more problems than others.
Left to their own devices, with so many cells acting independently, you’d encounter performance and safety issues with your E-bike.
So the BMS helps to provide your E-bike battery with long-term consistent performance.
We like to think of the BMS as the competent ride leader overseeing a group of different riding abilities and working to keep everyone together on the trails.
How we ensure the highest battery safety standards in our Liv E-bikes
At Liv, we take your safety VERY seriously. That’s why our E-bike batteries have been co-developed in partnership with the biggest and best battery manufacturer available – Panasonic.
Although other brands may purchase Panasonic batteries Liv has gone the extra mile. or two.
Firstly, we work closely with Panasonic to co-develop our batteries. The output is an e-bike battery that’s completely proprietary to us and designed to the highest safety standards.
Secondly, not only does Panasonic manufacture the cells and the battery management system on our E-bikes but they also assemble and test them for us.
So by investing in a Liv E-bike you can feel totally confident you’re getting a safe, reliable, and high-performing battery that’s developed, assembled, and tested by industry leaders. You won’t find our e-bike battery on any other e-bike on the market.
Liv’s EnergyPak E-bike battery is also distinct from other brands because it has individual separators (rooms) inside. This helps prevent heat from spreading from one cell to another.
Our BMS – aka the capable ride leader – monitors the battery pack and individual cells to make sure each cell is regulated for maximum efficiency and to prevent overheating.
While your Liv E-bike is charging, Liv’s Smart Charger continuously communicates with the battery to ensure individual cells are charged at the optimum rate. Also, in extremely hot or cold weather conditions the Smart Charger will adjust the charging voltage for optimal battery efficiency.
simple do’s and don’ts for ultimate E-bike battery safety
E-bike battery safety: The Do’s
- Do purchase your E-bike from a reputable e-bike brand.
- Do always use the battery and charger that originally came with your E-bike.
- Do go to an authorized dealer if your battery is damaged so they can check it before your next ride.
- Do remove your battery when transporting your e-bike to protect it from damage.
- Do store the battery at room temperature in a moisture-free environment to avoid unnecessary damage to the cells.
- Do keep the battery away from children and pets.
- Do stop the charging procedure immediately if you feel concerned.
E-bike battery safety: The Don’ts
- Don’t modify your E-bike or let your ‘helpful’ friend tinker with it either. For maintenance, always go to an authorized dealer for your E-bike brand.
- Don’t charge your E-bike around flammable materials.
- Don’t store your E-bike battery in a damp place.
- Don’t subject the battery or charger to high-impact eg. by dropping them
- Don’t cover the battery or charger or place objects on top of it.
- Don’t leave your battery at full charge if you’re storing it for a month or more. It is also best to remove the battery from the bike and store it at 60% of its capacity. You can make use of Liv’s Smart Charger which has a useful 60% charge function to ensure safe storage.
Now let’s look at the bikes.
OK. Battery tech talk–done. Serious face–gone. Now for the fun stuff because it’s time for you to start drooling over our awesome range of women’s E-bikes.
Panasonic finally enters US e-bike market with its own electric motors and batteries
Despite holding over 40% of the market for electric bicycles in Japan, Panasonic hasn’t yet made large inroads in the US. But now that is changing as the electronics giant has announced US partnerships to position its own batteries and electric motors on the road in North America.
Panasonic powered e-bikes coming to the US
According to Panasonic, global sales of electric bicycles is expected to reach 40 million by 2023. The company wants to ensure that they are able to serve as many of those global markets as possible. To break into the US electric bicycle market, Panasonic is entering into a partnership with the one of the largest bicycle manufacturers in North America, Kent International.
“ Panasonic. the world’s leading automotive battery supplier, and Kent International Inc., North America’s leading bicycle manufacturer. announce the entry of new electric-assist bicycle s into the eBike segment. To meet the changing micro mobility lifestyle trends, Panasonic is partnering on the launch of electric bicycles under two brands with three models.”
Those two brands include Univega USA and Van Dessel. Both will feature Panasonic’s proprietary battery packs and motors.
While electric bicycle battery packs featuring Panasonic battery cells have already been popular for years, these will be among the first Panasonic-produced battery packs on US e-bikes manufactured under the new partnership.
Panasonic sees this is an important opportunity. Not only did the US e-bike market grow by 25% last year, but just as many electric bicycles were sold in the US as electric cars. And since electric bicycles are a much more affordable way for consumers to get their feet wet with EVs, e-bikes can be an effective gateway to help move transportation towards electrification.
Van Dessel electric bicycles
Van Dessel has a national-championship winning line of bicycles, designed by Champion racer Edwin Bull. The company’s bikes are sought after by enthusiasts, professionals and olympic athletes.
Now the company has debuted two electric bike models, a mountain bike and a gravel bike. The electric mountain bike, known as Captain Shred, was designed from the ground up around Panasonic’s new GX0 motor. At just 2.95 kg, the GX0 mid drive motor generates an impressive 90 Nm of torque. That puts the Panasonic GX0 in a virtual tie with Brose’s Drive S Mag motor in the race towards the lightest and torquiest e-bike mid drive motors.
The Van Dessel electric mount bike with the new Panasonic GX0 motor will race in the UCI sanctioned first-ever eMountain bike world championship series.
Van Dessel’s gravel bike, known as the Passepartout, also employs the GX0 motor to create a lightweight road bike that can handle itself off the beaten path as well. The Passepartout pays homage to the old days of racing, back when all bikes in the Tour de France were gravel bikes. Without the nicely manicured roads of today’s races, being able to ride hard on pavement, dirt or gravel was a necessity.
Electric gravel bikes are becoming a growing market in the US, with Yamaha recently announcing its own electric gravel bike recently.
“ Panasonic is poised to elevate the exposure and growth of eB ikes. and because of that, Van Dessel is proud to bring two new performance eB ike models to the market, especially given their century-long expertise in the bicycling industry and providing connectivity across multiple industries. W e are eager to watch our customers experience our new eBikes to support their lifestyles and technology-driven interests.”
Univega USA electric bicycles
Unlike the high performance race bikes built by Van Dessel for elite athletes and enthusiasts, Univega USA creates bikes that are meant to handle more everyday commuting and recreational needs. The company is now showing off their new UVG-1 touring electric bicycle.
The UVG-1 features Panasonic’s X0 motor system. As the UVG-1 is a touring bike, it doesn’t require the same highly optimized motor used in the Van Dessel bikes. The X0 system is still a veritable powerhouse though. Weighing in at just 3.7 kg, the X0 motor provides 80 Nm of torque to assist riders during acceleration and when powering up steep hills.
With the bikes just being unveiled in the last few days, further specs and are still forthcoming. However, this is a strong showing from Panasonic as it charges into the US market, and may be a taste of what’s to come from Panasonic Automotive over the next few years.
What do you think of the new Panasonic-powered electric bicycles? Will they be enough to take on incumbents like Bosch and Shimano? Let us know in the Комментарии и мнения владельцев below.
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Which 18650 battery is best for an e-bike?
There are a lot of different 18650 batteries on the market, and it can be tough to know which one is best for your e-bike. In general, you’ll pay attention to a battery’s capacity (mAh rating), discharge rate (C rating), and compatibility with the e-bike’s controller.
In this article, we delve into the 18650 battery in more detail, battery specs, and how to identify the best 18650 battery for your e-bike.
What is a 18650 Battery?
A 18650 battery is a lithium-ion battery that can be recharged. The 18650 designation comes from the physical dimensions of the battery, which are 18 mm in diameter and 65 mm in length. The 0 represents the cylindrical shape of the battery.
18650 is one of the most common types of lithium-ion batteries. They are used in a wide variety of devices, including laptops, vapes, flashlights, and light electric vehicles.
Light electric vehicles such as e-bikes prefer 21700 and 18650 batteries.
How to Choose the Best 18650 Battery for Your E-bike
When choosing battery packs for your electric bike, you’ll want to consider the main factors:
Capacity
The capacity of a battery is measured in milliampere-hours (mAh). The higher the mAh rating, the more energy the battery can store. A higher capacity lithium-ion rechargeable battery will give you a longer range on your bike. A higher capacity also means that the battery will take longer to charge.
Continuous Discharge Rating
The discharge rate of a 18650 battery for an e-bike is measured in terms of continuous current (C). A higher C rating means that the battery can provide more current for a longer period without being damaged.
Higher Continuous discharge ratings are important if you’ll be using your bike for high-performance applications, such as racing or off-road riding.
Compatibility
It’s important to make sure that the 18650 lithium-ion batteries you choose are compatible with your bike’s controller.
Other factors that can guarantee you a good pack of li-ion for your e-bike include:
18650 e-bike cell manufacturers
Some 18650 battery brands are better than others in terms of quality and performance including continuous discharge rating.
There are many brands of 18650 batteries from reputable manufacturers, such as:
Panasonic 18650 lithium-ion batteries are among the most popular on the market. They are known for their high quality, good prices, and performance.
LG Chem 18650 is also very popular. They are known for their high energy density and long life.
Samsung SDI
Samsung 18650 is common in laptops and other devices. They are known for their high quality and reliability.
Sony 18650 is also common in laptops and other devices.
CATL is known for manufacturing high-quality 18650 lithium-ion. They are among the best batteries on the market with good prices.
BYD is a Chinese battery manufacturer. They are known for their good quality and competitive prices.
Toshiba 18650 li-ion are also common in laptops and other devices. They are known for their high expectancy and more power.
A123 Systems
A123 Systems is known for its high-quality 18650 li-ion. They are used in a wide variety of applications, including electric vehicles, digital cameras, and vaping devices amongst other devices.
18650 battery chemistry
The chemical composition of 18650 batteries is very important in choosing a rechargeable battery. The chemical composition includes:
Each of these chemistries has its advantages and disadvantages.
Lithium iron phosphate (FePO4) is the most stable of the four chemistries. It has a very low rate of self-discharge and is not susceptible to thermal runaway. However, LiFePO4 has a lower energy density than the other chemistries.
Lithium nickel cobalt aluminum oxide (NCA) lithium battery comes with a high power density and good stability. It is one of the most popular battery types on the market. It is quite affordable with a low continuous discharge rating.
Lithium nickel cobalt magnesium oxide (NCM) batteries are the most popular type of lithium battery on the market. They are affordable, have a long cycle of life, and are very stable. NCM is available in a variety of voltages, ranging from 3.6 volts to 4.2 volts.
The 18650 e-bike battery voltage
18650 batteries come in a variety of voltages. Your choice of 18650 e-bike battery voltage will ultimately depend on the voltage of your bike.
The e-bike battery voltage you choose will also affect the amount of power your bike has. A higher voltage battery will give your bike more power, while a lower voltage battery will give your bike less power.
Features of the 18650 battery packs for e-bike
Some 18650 batteries come with built-in protection circuits Multi-function Protective Circuit Board (PCM). PCM is used to protect the cells from overcharging, over-discharging, overcurrent, and short circuits.
Overcharging protection: When the cell charging voltage reaches a certain voltage, the charger will stop supplying current to prevent overcharging.
Over-discharge protection: When the cell voltage drops below a certain voltage, the device will stop using the cell to prevent damage from over-discharging.
Overcurrent protection: If the current exceeds a certain A, the PCM will shut down the circuit to prevent damage from overcurrent.
Short circuit protection: If a short circuit is detected, the PCM will shut down the circuit to prevent damage from a short circuit.
Cell balancing: The PCM will equalize the voltage of all the cells in the pack to prevent one cell from being over-charged or over-discharged.
Temperature protection: The PCM will shut down the circuit if the temperature gets too high to prevent damage from overheating.
Your budget
The price of an ebike battery can vary depending on the brand, capacity, discharge rate, and other features. Choose the battery that fits your budget and needs rather than just an expensive battery.
The durability of the 18650 battery for the e-bike
The 18650 should be of high quality and durable. This will save you money in the long run as you will not have to replace it often.
The battery should also be able to withstand extreme temperatures and maintain the bike’s power. This is important as the battery will be exposed to different weather conditions.
The Tritek 18650 e-bike battery pack can withstand temperatures as low as.20 degrees Celsius and as high as 60 degrees Celsius. This makes it a great choice for those who live in areas with extreme temperatures.