E-Bike Batteries: Volts, Amps, Watt Hours Explained
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What Are These Volts, Amps, and Watt-Hours? How Battery Specifications and Capacity Equate to Capability and Cost
Understanding e-bike batteries can be challenging, even for those of us in the know; the nitty-gritty details are figured out by electrical engineers with years of education and experience under their collective belts – and for good reason, it’s all chemistry and math over there!
You’ll encounter a host of terms when reading about e-bikes or looking at electric bike battery specifications: things like battery size, capacity, voltage, amp hours and watt hours. Some of these words are more-or-less interchangeable, others are related but distinct. All of them can be confusing, but they are also hugely important in understanding electric bikes and their capabilities – most notably when trying to interpret how far they can take you before needing to be recharged.
In this guide to e-bike batteries, the helpful writers at Electric Bike Report will help you to understand the meaning of common battery terms and their relation to the performance of the electric bikes they power.
E-Bike Batteries Explained
Batteries are one of the core elements of electric bikes. They are needed to supply power to the motor, which in turn provides assistance to the rider, and reduces the amount of human effort needed to move the bike.
E-bike batteries come in various sizes, and can be mounted to the frame in different ways. Some are fully internal, and are sealed inside the bike’s frame. As such, they are not removable, except by using special methods and tools available to professional technicians. Others are removable for easier charging and replacement, whether mounted completely externally (outside the frame), partially recessed (sunken into the frame to some degree), or completely recessed (sunken entirely and nearly invisible on the bike).
Regardless of their type, all e-bike batteries are actually battery packs, and are made up of groups of cells, similar to the standard AA or AAA batteries used in everyday applications. The number of cells and the method used to cluster them together determines how quickly they can provide power and how long they can continue to supply it.
In contrast to standard AA or AAA batteries, however, those used in e-bikes are most commonly rechargeable lithium-ion batteries similar to those used inside smartphones and in conjunction with cordless power tools. Lithium-ion batteries are efficient and can be recharged hundreds or even thousands of times if cared for properly. The Light Electric Vehicle Association, or LEVA, has a great article that they allowed us to re-publish regarding proper battery care and safety to ensure maximum life span.
Fully integrated batteries such as the one on the Velotric Nomad 1 can match the bike’s color and disappear into the frame.
Electric Bike Battery Terms and Definitions
Before we dive deeper into the details, let’s consider a couple of examples of e-bike battery specifications in relation to how they usually appear:
V = Volts and Ah = Amp-hours
V = Volts and Wh = Watt-hours
Both examples convey two basic measurements, albeit a little differently. In both examples, we see volts first; this measurement relates to the availability of the electrical energy the battery can deliver. Next, either amp-hours or watt-hours are shown; these represent a battery’s capacity, or the amount of power it can store.
Let’s define these words (and a few helpful additional terms) a bit more clearly:
Current: the flow of electricity, or transfer of electrons, through a circuit.
Circuit: a closed system of wires and electrical components through which current can travel.
Volts (V): the amount of electrical force or pressure the battery can produce; the speed of the battery’s output of current. This is also sometimes referred to as the electromotive force, and is more specifically the speed at which electrons move through the system.
Note that this is a nominal rating that is used for classification purposes. In reality, a battery’s voltage varies based on the amount of power being drawn from it at a given moment, as well as the battery’s present level of charge. As current is drawn from the battery, its voltage decreases. This can be seen in an e-bike battery voltage chart.
Voltage is determined by the number of battery cells arranged “in series”.
Amps or amperes (A): a measurement of the strength of the battery’s output, or current. specifically, the volume of electrons passing through the system. This is limited by the size of the wires making up the system. Larger wires allow more current, smaller wires allow less. Generally, systems with higher voltage should use smaller wires (that limit amperage) to prevent overheating.
Amps can also be thought of as the amount of energy being drawn from the battery by what it is powering, and can fluctuate from moment to moment. In the case of e-bike batteries and their motors, a greater number of amps are drawn as the motor works harder (i.e. going uphill or using only the throttle).
Amp-hours (Ah): a measurement of charge; the amount of energy that can be delivered through an electrical system over the course of an hour.
In the case of a 10 Ah battery, it can deliver 10 amps of power in one hour, or 1 amp of power for 10 hours, etc, depending on the needs of the component that is delivering power to.
Amp-hours are determined by the number of clusters of battery cells arranged “in parallel”.
Watts (W): a unit of power, determined by volts and amps; the amount of work that can be done by one amp of current delivered at 1 volt. The amount of work is determined by the rate at which the energy is used.
This measurement is generally applied only to an e-bike’s motor, but its battery must support the motor’s needs.
Watt-hours (Wh): another measurement of capacity. In this case, the amount of work that can be done, or the amount of power that is spent, over the course of an hour. This is a direct result of a battery’s voltage multiplied by its amp-hours.
As such, a 24V, 20 Ah battery and a 48V, 10 Ah battery might look different on paper, but they have about the same amount of energy. This makes watt-hours a more reliable indicator of capacity when comparing different batteries.
Controller: A device that limits the flow of electricity through a circuit, and prevents a battery from discharging its energy all at once. In terms of an electric bike, this is the “brain” that adjusts the pedal assist system, the amount of input the motor contributes, and the e-bike’s speed.
Ecotric 48V Fat Tire Portable and Folding Electric Bike with LCD display-Black and Blue
- Vendor: 699
- Product Type: e-bike
- Barcode: 6974718201919
SHIPPING AND DELIVERY
- We offer free shipping on all of our bikes everywhere within the lower 48 states!(Excludes: Alaska/Hawaii,Puerto Rico, US Protectorates, APO/FPO, PO Box)
- Shipping time varies from 2-3 business days if electric bike is in stock
- Delivery time varies between 6-8 business days if electric bike is in stock
- Shipping is offered through UPS/FEDEX/USPS
- Orders are shipped directly from Oakland,CA or Mobile, AL
- details,click here
RETURNS AND WARRANTY
- Free Returns 30-Day At Home Trial. details,click here
- Every ECOTRIC electric bicycle purchased on our website comes with an 18 months warranty ( In the period of 18 months from purchase by Official Authorized Store) against manufacturing defects in materials or workmanship on its frame, battery, motor, controller, and display.
- Please note that we do not accept the return of the spare parts or accessories(except battery).
- details,click here
Customer Reviews
Delivery was fast, price was great and the bike is pretty good. I only had it a week or two and I love it. I want to ride it every day. I fine it very durable but smooth ride.
I really like the 5 levels of power when peddling if there were one more higher gear for level 4 that would be good but all in all my third one and I like it
I dont have many miles on my folding fat tire but so far it has preformed great. Not quite as fast as my wife’s Lectric bike but still a solid bike. Looking to do some upgrading on it soon.would buy again
I bought this Cheetah last week. It was fairly easy to assemble it, read the manual first it is quite good. Charged up the battery and away I went, great fun to ride and tackles hills with no problem. Went for a 17 mile ride on a local rail trail using. Mostly 1 2 levels of assist. Did not use much battery, so I reckon it is good for the 23 miles full assist and up to 45 with partial assist. Very easy to ride and get used to the controls. Mine came with a front headlight which is quite bright, it also has telescopic front forks and a sprung saddle post. both of which handles the bumps quite well. Very pleased with this purchase, and have no hesitation in recommending it. Fits nicely in the back of the wife’s Mazda CX-5, I remove the battery to make it a bit lighter for lifting into the CX5. Looks like it would fit in my BMW5 series too.
Ordered on a Monday, delivered on Thursday so super quick shipping! The assembly instructions were very detailed and easy to follow, assembly took only about 30 minutes. It came almost fully charged and the tires were adequately inflated so I was able to take my first ride in no time. Everything about the bike seems well made and functions properly. I wouldn’t hesitate to buy another Ecotric product or to recommend them to my friends! Thanks for a great product Ecotric!
Electric Bike Battery Range: How Far Can I Go?
One of the most common questions for ebike buyers is about range, or how far you can go on a single battery charge.
The answer to this question usually is “well, it depends.”
It Depends on What?
The range the battery will give you depends on the capacity of the battery, and on the nature of the ride or trip.
That is, it depends on the nature of the battery in terms of its power and capacity to store energy, and how much energy you are using during the ride.
Essentials of Electric Bike Batteries
Let’s start with some basic understanding of what ebike batteries are and why different batteries get different ranges.
Today’s ebike batteries are made of lithium-ion cells. It’s the same technology you have in your cellphone, many consumer electronics and electric cars.
Inside the electric bike battery, there are multiple battery cells. Individually, these cells look much like the AA batteries you might put in a flashlight.
The cells get wired together to create one battery.
The quality of the electric bike’s battery cells do matter. Look for ebikes with batteries made of cells from top known brands like Panasonic or Samsung. they’ve been at this for a while, and make lithium-ion batteries for a range of applications.
The power (speed) and capacity, or amount of energy available in your battery, is determined by the size and number of cells, and how they are linked together.
How do you know what speeds and distances your ebike’s battery is capable of? Understanding the battery’s specifications will help.
Electric Bike Battery Specifications
Ebike battery specifications will be presented to you by three primary factors:
- Volts (power, speed)
- Amp hours (how much energy can be delivered)
- Watt hours (maximum capacity)
What are Volts?
Volts refers to the amount of power, or speed at which electrons can move through the system. The higher the volts, the faster the battery can spin your motor and wheels.
Volts matter because it they you a little more about the speed abilities of the battery and motor.
36-volt and 48-volt batteries are most common on ebikes. While 36-volt batteries are common on smaller, lighter and low-budget ebikes, the 48 volt batteries best suited for fat tire electric bikes and for getting to speeds of 25 miles per hour.
Larger voltage batteries, like 52 volts are generally overkill for most ebike uses, and are more suited to ‘scooter’ or ‘motorcycle’ power and speed requirements.
48-Volts is perfect for most ebikes, especially fat tire electric bikes!
What are Amp-Hours?
You will also see batteries specified for Amp-Hours. Amp-hours tell you how much energy can be delivered, over time. An amp is how much energy flows per second, an amp-hour is how much energy flows per hour.
In short, Amp-hours are how much energy can be moved from the battery to your electric bike motor over time. This is a strong indicator of the potential range of your ebike.
Together, voltage and amp-hours tell you about the potential speed you can ride at, and how much energy the battery can provide over time.
Ebike batteries generally range in amp-hours from 10 AH to 21 AH.
Remember: amp-hours are a strong indicator of the amount of energy the battery can provide on a single charge.
So How Far Can I Go On My Ebike Battery?
This is where the volts and amp-hours help, because we can multiply them together and get Watt-Hours, which is a good indicator of the overall Capacity of the battery, and can be compared across batteries with various volts and various amp-hours. The higher the Watt-Hours, the higher the capacity.
Volts x Amp Hours = Watt Hours
And capacity is what really tells us more about how far you can go.
Watt Hours = Capacity
Here’s a rider who benefits from more watt-hours on his long electric bike rides up in hilly Summit County, Colorado:
For example, let’s say we have a 48 volt battery with 14.5 amp-hours. The capacity of this battery is 696 Watt-hours.
48 Volts x 14.5 Amp Hours = 696 Watt Hours
Or, let’s say we have a 48 volt battery with 19.2 amp hours. This battery has a capacity of 922 watt hours.
48 Volts x 19.2 Amp Hours = 922 Watt Hours
Same voltage, but 32% more capacity. That means, all other things equal, you could go 32% further with this battery.
32% more range? Nice!
So What Does Watt-hours and Capacity Indicate The Range of My Ebike?
The battery capacity has a direct influence on the potential Range of the electric bike.
If we know the battery Capacity, and we can start to estimate the range, depending on how many watt-hours you are using per mile of riding.
Actual use of your battery’s capacity. and your resulting range. depends on a lot of factors, including how hilly your route is, how much you pedal, reliance on higher pedal assist modes, use the throttle, your weight, the amount of wind, and more.
How much energy are you using from the battery? On the low end, your fat tire ebike is going to use anywhere from 10 or 15 watt hours per mile. that’s with steady pedaling and some moderate pedal assist.
On the higher end, if you are using a lot of throttle and higher pedal assist modes, you’ll be using 20 to 25 watt hours per mile, maybe even more.
So let’s say you like to pedal and use a moderate pedal assist mode of 3 or 4 most of the time and are traveling over moderate terrain. You are likely using about 15 watt hours per mile.
That means your 48 volt, 14.5 amp-hour battery. with a total of 696 watt hours. will give you a range of 46 miles at that usage level.
696 watt hours / 15 watt hours per mile = 46 miles range
Or, let’s say you really like to accelerate fast with the throttle, and go fast with a steady pedal assist level of 5. You are likely using at least 20 watt hours per mile. That gives you a range estimate. on the same battery. of 35 miles.
696 watt hours / 20 watt hours per mile = 35 miles range
That’s over ten miles of range difference, so you can see that your riding style really does matter.
Now, think about those bigger amp-hour batteries. A 48 volt battery with 16 amp hours has 768 watt-hours. This will boost your range estimates up to 51 miles at that lower pedal assist usage, and 38-40 miles for faster acceleration and speedy trips.
Want even more capacity and range? A 48 volt 21 amp-hour battery has over 1000 watt-hours. The range on this battery is another 31% bigger than the 48 volt 16 amp-hour battery,
With this battery, you’ve easily got a range of 67 or more miles at moderate pedal assist modes, and an ample 40-50 miles if you are using the throttle and pedal assist more aggressively.
Here’s a summary of common ebike battery sizes and range estimates:
So What Capacity Battery Do I Need For My Ebike?
Well, that depends. Sorry, just kidding!
Jokes aside, it really does depend on the type of riding you plan to do.
If you are doing mostly short, local trips, a smaller capacity battery should be just fine, though you may have to recharge more frequently and sacrifice some speed and power.
If you are planning to commute, or do longer rides for fun, a larger battery capacity will ease any ‘range anxiety’ and reduce the frequency that you need to recharge your battery. Need to recharge a lot? Get a high speed electric bike battery charger to reduce charging time.
All that said, it’s often better to go with a larger battery than you think you will need, so you have maximum power more of the time. You can also buy a spare or replacement electric bike battery.
Some words of caution: A lot of ebike brands will cut corners to keep their a little lower and profits a little higher. Often, that’s in the battery quality and size. Small cuts in battery size and quality might save you a few hundred dollars, but you sacrifice the long term fun and performance of your ebike.
Here’s another part of the FattE-Bike difference: We provide top quality ebike batteries with appropriate capacities, so you get where you want to go on your ebike. and back.
Ready to get an ebike with excellent speed and range? Shop Now.
How Long to Charge a 48v Ebike Battery? Don’t Overcharge
The battery of an ebike supplies power to the motor and there are various types of ebike batteries available such as 36v, 48v, 52v, 60v, and 72 volts. The majority of electric bikes come with 48v batteries because of their excellent efficiency, superb power, longer range, and speed.
Charging an ebike battery with the right charger is very simple but most people don’t know how long to charge 48v ebike battery to maintain its performance for a long period of time.
Don’t worry! This article will help to understand the charging time of a 48v electric bike battery, factors affecting charging time, and important faqs related to your query.
How Long to Charge 48v Ebike Battery?
You need a charger that is compatible with your 48v battery. When you have the right charger for your ebike battery, it may take somewhere around 4-6 hours to fully charge the 48v ebike battery from zero percent.
I mean your charger voltage must be equal to your battery’s voltage i.e., you need a 48v charger to charge 48v ebike battery. And the charger comes with different Amp ratings such as 2-Amp, 3-Amp, 4-Amp, and so on.
Avoid overcharging your ebike battery as it may get damaged internally which will reduce its lifespan. It is advised to charge your ebike battery to 80% only. However, If you are charging the 48v battery for the first time, 8 to 12 hours of charging time are recommended.
Honestly, I charge my 48v 10ah step-over ebike for 4 hours with a 3 amp charger. Also, I set up a reminder alarm so that I do not forget to disconnect the charger. As well as I have done a charging experiment with different types of chargers with 48v 10ah battery, here are the results:
48V 10Ah charging time according to the charger type
Most ebikes are equipped with a 48V 10Ah lithium battery i.e., 480Wh. This battery can easily manage up to a 500-watt ebike motor. You know, It’s very simple to calculate the charging time for an ebike battery, Here is the formula:
Ebike battery charging time = Battery’s AH/Charger Amp
| 2 Amp Charger | 5-6 hours |
| 3 Amp Charger | 4-5 hours |
| 4 Amp Charger | 3-4 hours |
| 5 Amp Charger | 2-3 hours |
| 6 Amp Charger | Upto 2 hours |
As you can see the high amp chargers are taking less time and vice-versa. I would not recommend using high amp chargers to charge a 48v ebike battery. Use only those chargers that your brand recommends. Let’s see the charging time for 48v batteries with various AHs.
48v 20Ah charging time according to the charger type
48v 20ah ebike battery is a very powerful battery i.e., 960Wh. It takes more time to fully charged as compared to a 48v 10ah battery. As it is a powerful battery so it does not come with a 2-Amp charger. Therefore, we have tested this battery with 3-Amp to 6-Amp chargers.
| 3 Amp Charger | 6-7 hours |
| 4 Amp Charger | 5-6 hours |
| 5 Amp Charger | 4-5 hours |
| 6 Amp Charger | 3-4 hours |
Also, charging time may vary because there are many factors that affect charging time. Let’s discuss them.
How Long Does a 48v Battery Last?
As you know that the 48v ebike battery is powerful and generally takes around 4-6 hours to fully charged with a 3-Amp charger. However, It’s also important to know how long does a 48V ebike battery last on one charge, and for what distance (48v ebike battery range).
Ebike battery’s range is dependent upon its Amp-hours (AH). Higher AH provides more range on an ebike and vice-versa. Also, there are other factors such as type of terrain, rider’s weight, weather conditions, and so on.
Let’s discuss in detail how long will a 48V battery last with various AHs.
How long will a 48V 10AH battery last?
48V 10Ah ebike battery is the basic model for an ebike battery which has electric power up to 480 WH (It can provide 480w electricity in an hour to an ebike motor). And this ebike battery can be paired with a 250w ebike motor, 350w ebike motor, and 500w ebike motor.
A 250w ebike consumes less power than the 350w and 500w ebike motors resulting in more range, hence a 48V 10Ah battery lasts for around 2 hours with a 250w ebike motor.
A 48V 10Ah electric bike battery would last for:
| 250-Watt | 2 hours |
| 350-Watt | 1.5 hours |
| 500-Watt | 1 hour |
How long will a 48v 20ah battery last?
A 48V 20Ah lithium battery has electricity power of up to 960 WH, Which means it can provide 960 watts of power to an ebike motor in an hour. Below is the table which shows how many hours will a 48v 20Ah battery last with various ebike motors.
| 500-Watt | 2 hours |
| 750-Watt | 1.5 hours |
| 1000-Watt | 1 hour |
Is a 48v Battery Good for Electric Bikes?
48-volt electric bike battery is the most popular because it is powerful, efficient, lasts for long hours, longer range, and provides amazing speed to ebikes.
However, ebike batteries with 48 voltage have more weight than the 36v battery. It adds some extra weight to the ebike which affects the speed of the bike as well as takes more time to get fully charged.
Well, everything in this world comes with some pros and cons. So 48v ebike battery is. Overall, I have been using a 48v ebike, I must admit that it’s an amazing battery for an ebike in all aspects.
As well as 48v electric bike battery charging time is also not so long, it usually gets charged in around 4-6 hours.
How to Charge 48v Ebike Battery? Remember this Simple Process
Charging an ebike battery is not rocket science, whether you have a 36v or 48v battery or any other type of ebike battery. It’s very simple to charge them using the correct charger.
Regular charging your ebike is one of the important tips for electric bike riders. You might not know if you are a beginner and riding an ebike for the first time. Don’t worry here it is.
Take the battery out of your ebike if it is detachable and plug the charger into the socket and connect it to your battery, turn on the switch and your battery will start charging.
If your ebike battery is fixed inside the frame, you are given a socket nearby the frame where you have to plug the charger and connect it to the electric board and turn on the switch. Your battery will start charging.
How long does it take to charge a 48v battery with a 3 Amp charger? If you are charging the 48v ebike battery with a 3 amp charger, it will take around 4 to 6 hours to charge fully. Results may vary from battery brand, type of battery, charger amperage, state of charge of the battery, and temperature.
Watch this video tutorial to charge a 48v ebike using the right charger:
Bittoo Gupta
I am the founder and editor of The Bike Fetcher, a passionate E-Biker. My passion for E-bikes led me to build this blog site where I share electric bike news updates, my e-biking experience, e-biking tips, e-bike battery tips and help people to get the best e-bike. Feel free to contact me on my social accounts or through the contact form.