How to choose the right battery for your electric bike

The battery can be said to be the most important component of an electric bicycle. As a new or prospective electric bicycle user, we believe you have already realized the importance of an electric bicycle battery. However, most electric bicycle users have a common question: How do you choose the right battery for your electric bicycle? How do you know which one is the best among all available battery types? What type of battery should I buy for my electric bicycle?

 

In this guide, we will answer all the questions that trouble you. The article also contains information about different types of electric bicycle batteries available for you to use. Additionally, we will enlighten you about the factors to consider before choosing an electric bicycle battery. Keep reading to learn how to select the best battery for your electric bicycle.

 

Basic Electric Bicycle Battery Terminology:

Before choosing the best battery for your electric bicycle, you must be able to understand the terminology used to describe electric bicycle batteries. We will define some terms that will help you have a better understanding of batteries.

         

Here is a list of commonly used terms when discussing electric bicycle batteries:

 

Ampere (Amp)

Ampere-Hour (Ah)

Voltage (Volt)

Watt (W)

Watt-Hour (Wh)

 

Ampere (Amp):

This is the unit of electric current. It is an internationally recognized standard unit. You can compare amperes to the size or diameter of a pipe through which water flows. This means that more amperes indicate a larger pipe with more water flowing per second.

 

Ampere-Hour (Ah):

This is the unit of charge, and it represents the relationship between electric current and time. It is a measure of battery capacity. A battery with approximately 15Ah can discharge continuously at 1.5A for ten (10) hours or at 15A for one hour.

 

Voltage (Volt):

This is commonly referred to as volts. It is the static electric potential difference between two (2) conductors, the live conductor and the neutral conductor. The optimal voltage reading for an electric bicycle battery is 400 volts.

 

Watt (W):

This is the standard unit of power. The higher the wattage, the higher the power output of the electric bicycle. Additionally, one (1) watt is equal to one (1) volt multiplied by one (1) ampere.

 

Watt-Hour (Wh):

This is the unit of power for a given period of time. It measures the total power output over a given time. It does not regulate the power output at a particular moment like watts. Think of it as speed and distance. For example, if your car's speed is measured in watts, then the distance from one place to another is measured in watt-hours. So, if your electric bicycle's battery discharges at a power of 100W for two (2) hours, it has consumed 200Wh.

 

Nominal voltage is sometimes used to refer to voltage measurements in electric bicycle batteries. This is because each battery cell in a battery can withstand a certain range of voltages.

 

Now that you have an understanding of the basic terms, we will explain different types of electric bicycle batteries. From the very beginning, the battery has been a determining factor in your enjoyment and value of an electric bicycle. Here is a list of the most common types of electric bicycle batteries in the market.

         


Battery Types

Lead Acid

Nickel Cadmium

Nickel Metal Hydride

Lithium-ion

 

Lead Acid Batteries:

Lead acid batteries are known for being very inexpensive. However, they have lower power output and are quite heavy. Compared to other battery types of the same weight and size, they have smaller capacity. Lead acid batteries have three main uses.

 

They can be used as backup power sources for stationary applications. They also contribute to deep cycle applications such as golf carts, scissor lifts, etc. Finally, they are used as starter batteries for automotive motor systems. They can also be used for electric bicycles. However, their weight and power output mean that we do not recommend their use.

 

Lead acid batteries are the heaviest among all types of electric bicycle batteries. They are three times heavier than lithium batteries and twice as heavy as nickel batteries. Additionally, lead acid batteries have smaller battery capacity compared to nickel and lithium batteries. The maximum capacity of lead acid batteries is half that of lithium and nickel batteries.

 

Nickel Cadmium Batteries:

These types of batteries are very durable and can last a long time if properly maintained. Additionally, they offer higher battery capacity compared to lead acid batteries but much less than lithium batteries.

 

Moreover, nickel cadmium batteries have excellent load performance. They can withstand a great deal of pressure from the throttle.

 

However, they also have some drawbacks. Their self-discharge rate is quite significant. When fully charged and not in use, the battery level can drop to as low as 70% within 24 hours. Their power density is low as well.

 

Furthermore, nickel cadmium batteries are expensive, and their main component, cadmium, is a hazardous pollutant. Due to environmental safety and recycling concerns, nickel cadmium batteries are often phased out of the market. These types of batteries are not the right choice for electric bicycles.

 

Nickel Metal Hydride Batteries:

Nickel metal hydride batteries are an improvement over the previous two battery types—lead acid and nickel cadmium. Even in self-discharge situations, nickel metal hydride batteries can hold 45% more charge than nickel cadmium batteries. However, they lack proper durability. Their maintenance is unstable, and charging can be a complex task.

 

Even with limited use, nickel metal hydride batteries generate heat quickly. This leads to high self-discharge. While the discharge rate is not as high as nickel cadmium batteries, they are not recommended for electric bicycles.

 

In terms of range improvement, nickel metal hydride batteries have almost no advantage over nickel cadmium batteries; they are more expensive. Despite this, they are more efficient and productive compared to lead acid and nickel cadmium batteries.

 

In terms of market share, nickel metal hydride batteries are rapidly losing value due to the presence of lithium-ion batteries. They are considered too expensive and have limited power output. Therefore, they are not the ideal choice for electric bicycles.

 

Lithium-ion Batteries:

Lithium-ion batteries automatically become the default battery for every electric bicycle in today's market. They power around 90% of electric bicycles on the market. Lithium-ion batteries generate more power output compared to other battery types for their weight. Most importantly, they are more durable and have a longer lifespan.

 

Furthermore, lithium-ion batteries are primarily divided into three types. These types have some differences, but they have one common aspect: they last longer.

 

On the other hand, they are compact and require functional electronic components to prevent them from catching fire or self-destructing. However, these are not concerns you should worry about. Manufacturers always have safety mechanisms in place to prevent accidents. However, it is still crucial to understand how to handle and maintain them properly.

 

Despite the expensive price tag, we recommend purchasing lithium-ion batteries for your electric bicycle. They are the ideal battery type for every electric bicycle in terms of range, weight, lifespan, etc. Here are the three types of lithium-ion batteries.

 

Lithium Manganese Battery (LiMg204):

This is the newest type of lithium-ion battery. They have good durability and range. Additionally, manufacturers claim that they have a longer lifespan compared to other lithium batteries. You might be interested to know that this battery type is currently used in some hybrid cars.

 

Lithium Cobalt Battery (LCo):

This is another type of lithium-ion battery. It has been on the market for a longer time compared to lithium manganese batteries. It is believed to have higher energy density compared to other lithium batteries. Additionally, it provides you with the highest power output, is lightweight, and reliable.

Lithium-ion Polymer Batteries (Li-pol)

This type of lithium battery is no different than other lithium-ion batteries in terms of weight, price, and range. Nevertheless, as a polymer, lithium polymers can undergo different moulding processes to bring out fantastic shapes.

 

They do not contain any liquids and requires less protective battery casing compared to other lithium batteries. This liquid-free feature means they are less vulnerable and provide more stability. Hence, they are ideal for use in low power applications – like electric bikes.

 

For a pleasant riding experience with your electric bike, we recommend a Lithium-ion battery for you.

Things to look out for before choosing a Lithium-ion Battery

In choosing a lithium battery for your electric bike, you need to consider the voltage and ampere ratings. This is important as it determines the range, durability, and power input of your battery.

 

Volts and amperes ratings are the two major talking points when choosing the right battery for your electric bike. You should know that selecting the wrong voltage/ampere rating can damage your e-bike or cause a fire outburst.

 

Voltage

Every electric bike has a unique input volt range. This means you can only power your electric bike with the exact voltage required to power it. You should not power your electric bike with a battery with a voltage that is more or less than the recommended range. This is necessary to avoid complications.

 

Using a battery with lesser voltage means you will not have enough power to significantly run your bike’s motor system. However, using a higher voltage can damage the sensitive electrical parts of the motor system. Most electric bikes accept nominal voltages – 36 volts or 48 volts. Generally, electric bikes come outfitted with a 18650 cell.

 

Lithium cobalt battery cells can hold up to 4.3v with a full charge and about 3.1v after discharging.

 

For example; if your bike has a lithium manganese cell, with a rating of 49volts and 13 cell clusters. Each cluster has an average voltage of 3.8v.

 

Here is how to calculate the average voltage of your battery;

 

3.8volts x 13 cells = 49.4volts or 49V average.However, after a full charge; this “49v” average battery will hold 4.3v * 13 cells = 55.9volts. As you discharge the battery, it will reduce every cell to 3.1v from 4.3v – minimum volts of 3.1v * 13 = 40.3v.

 

This average voltage range will help you determine if this battery is compatible with your bike. Voltages are converted to speed on your electric bike. If you choose a battery with higher voltage ratings within the motor limit, all things being equal, you’ll reach new top speeds.

 

Amperes

Amperes are virtually the measure of the flow of current at a specific voltage. In reality, the amperes are a measure of your bike’s torque. With more available amperes for your electric bike’s motor system, one thing is sure, more torque.

 

So, with your 49v 13Ah battery, your electric bike can peak at 68A with a continuous draw of 45A.

 

However, most motor systems can only pull as much current as they need. Therefore, choosing a battery with a high current output will not damage your electric bike’s motor.

 

This means if volts are the “speed” in your e-bike, amperes are how fast your electric bike’s battery can deliver this speed. More volts naturally gives more speed. Also, a higher amperage rating means more speed per second or hour. This means the power you get from your electric bike battery will determine your torque.

 

       

 

To sum it all

Choosing the best type of Lithium-ion battery for your electric bike can be complicated.  However, lithium cobalt is outstanding, and it offers higher energy density than others. This doesn’t mean other types of Li-ion batteries are bad for your electric bike.

 

Lithium manganese batteries are more ecologically friendly and safer. Lithium manganese also offers a higher cell voltage than lithium cobalt batteries. However, the energy density of lithium manganese is 20% less than that of lithium cobalt batteries.

 

Finally, lithium manganese also has extra advantages in terms of lithium-ion chemistry – including higher temperature performance and lower cost. Also, your budget is a big determinant of the kind of Li-ion battery you will buy.

 

Choosing the best type of battery for your bike is essential. It’s the only way that you will be able to enjoy using your bike without any hiccups. We are available to answer any questions that you may have about electric bike batteries. Contact us today.