Technical Guide: Electric Scooter Battery
Electric scooter battery
The battery is the “fuel tank” of your electric scooter. It stores energy consumed by DC motors, lights, controllers and other accessories.
Most electric scooters will be equipped with some type of lithium-ion battery pack because of their excellent energy density and service life. Many children’s electric scooters and other cheap models contain lead-acid batteries. In a scooter, the battery pack consists of a single battery and an electronic device called a battery management system to ensure its safe operation.
Larger battery packs have greater capacity (in watt hours) and allow electric scooters to travel farther. However, they also increase the size and weight of the scooter—making it less portable. In addition, the battery is one of the most expensive components in a scooter, so the overall cost will increase accordingly.
18650 lithium-ion batteries, as shown above, constitute the battery pack of an electric scooter | Image source: Wikimedia Commons under CC BY-SA 3.0.
An electric motorcycle battery pack consists of many individual battery cells. More specifically, they are made of 18650 battery cells, which is the size classification of lithium-ion (Li-Ion) batteries with a cylindrical size of 18 mm x 65 mm.
Each 18650 cell in the battery pack is quite unremarkable-it produces a potential of ~3.6 volts (rated) and has a pacity of about 2.6 ampere hours (2.6 A·H) or about 9.4 watt hours (9.4 watts).
The operating voltage of the battery ranges from 3.0 volts (0% charge) to 4.2 volts (100% charge).
Lithium-ion batteries have excellent energy density, which is the amount of energy stored per physical weight. They also have an excellent lifespan, which means they can be discharged, charged or “cycled” many times and still maintain their storage capacity.
Lithium ion actually refers to many battery chemistries involving lithium ion. Here is a short list:
Lithium manganese oxide (LiMn 2 O 4); also known as: IMR, LMO, lithium manganese
Lithium Manganese Nickel (LiNiMnCoO 2); also known as INR, NMC
Lithium nickel cobalt aluminum oxide (LiNiCoAlO 2); also known as NCA, lithium aluminum
Lithium nickel cobalt oxide (LiCoO 2); also known as NCO
Lithium cobalt oxide (LiCoO 2); also known as ICR, LCO, lithium cobalt oxide
Lithium iron phosphate (LiFePO 4); also known as IFR, LFP, lithium phosphate
Each of these battery chemistries represents a trade-off between safety, longevity, capacity, and current output.
Lithium Manganese (INR, NMC)
Fortunately, many high-quality electric scooters use INR battery chemistry-one of the safest chemicals. This battery provides high capacity and output current. The presence of manganese reduces the internal resistance of the battery, allowing high current output while maintaining low temperature. Therefore, this reduces the chance of thermal runaway and fire.
Some electric scooters with INR chemical composition include WePed GT 50e and Dualtron models.
Lead acid is a very old battery chemical that is commonly found in automobiles and some large electric vehicles (such as golf carts). They are also found in some electric scooters; most notably, cheap children’s scooters from companies such as Razor.
The advantage of lead-acid batteries is that they are cheap, but their energy density is very low, which means that they weigh a lot compared to the energy they store. In contrast, the energy density of lithium-ion batteries is about 10 times that of lead-acid batteries.
In order to build a battery pack with a capacity of hundreds or thousands of watt-hours, many individual 18650 lithium-ion batteries are assembled together to form a brick structure. The brick battery pack is monitored and regulated by an electronic circuit called a battery management system (BMS), which controls the current flowing in and out of the battery.
Schematic diagram of battery parallel and series
The individual cells in the battery pack are connected in series (end-to-end), and their voltages are added together. This is the possibility of scooters with 36 V, 48 V, 52 V, 60 V and even larger battery packs.
These individual wires (many batteries connected in series) are then connected in parallel to increase the output current.
By adjusting the number of batteries in series and parallel, electric scooter manufacturers can increase the output voltage or maximum current and ampere hour capacity.
Changing the battery configuration will not increase the total energy stored, but it effectively allows the battery to provide more range and lower voltage, and vice versa.
Voltage and remaining percentage
Each battery in the battery pack typically runs from 3.0 volts (0% charge) to 4.2 volts (100% charge).
This means that the operating voltage of a 36 V battery pack (with 10 batteries in series) ranges from 30 V (0% power) to 42 V (100% power). You can view the relationship between the remaining percentage of each type of battery and the battery voltage in our battery voltage chart (directly displayed by some scooters).
Every battery suffers from a phenomenon called voltage dips.
Voltage sags are caused by a variety of influences, including lithium ion chemistry, temperature, and resistance. It always leads to non-linear behavior of the battery voltage.
Once a load is applied to the battery, the voltage drops immediately. This effect can lead to incorrect estimation of battery capacity. If you read the battery voltage directly, you would think that you immediately lost 10% or more of its capacity.
Once the load is removed, the battery voltage will return to its true level.
Long-term battery discharge (such as long-distance riding) will also cause voltage dips. The lithium chemistry in the battery takes some time to catch up with the discharge rate. This may cause the battery voltage to drop faster during the end of a long ride.
If you let the battery rest, it will return to its true and accurate voltage level.
The rated unit of the battery capacity of an electric scooter is watt-hour (abbreviated as Wh), which is a measure of energy. This unit is easy to understand. For example, a battery with a rated power of 1 Wh can store enough energy to provide one hour of power.
For a given motor size, more energy capacity means higher battery watt-hours, which means that the electric scooter has a longer cruising range. An ordinary scooter has a capacity of about 250 Wh and can travel about 10 miles at an average speed of 15 miles per hour. The high-performance scooter has a capacity of several kilowatt-hours and a cruising range of up to 60 miles.
The single lithium-ion battery in the battery pack of an electric scooter is manufactured by only a few different internationally renowned companies. The highest quality batteries are manufactured by LG, Samsung, Panasonic and Sanyo. These types of batteries often only appear in the battery packs of high-end scooters.
Most of the battery packs of cheap and commuter electric scooters are made of GM’s made in China batteries, and the quality varies greatly.
The difference between branded battery scooters and GM China scooters is that they have greater assurance of quality control with well-known brands. If this is not within your budget, then make sure you buy the scooter from a reputable manufacturer that uses quality parts and has good quality control (QC) measures.
Some examples of companies that may have good quality control are Xiaomi and Segway.
Battery Management System
Although lithium-ion 18650 batteries have amazing advantages, they have lower tolerance than other battery technologies and may explode if used improperly. It is for this reason that they are almost always assembled into battery packs with battery management systems.
The battery management system (BMS) is an electronic component that monitors the battery pack and controls the charging and discharging. Lithium-ion batteries are designed to operate between approximately 2.5 to 4.0 V. Overcharging or completely discharging can shorten battery life or cause dangerous thermal runaway conditions. The BMS should prevent overcharging. Many BMSs also cut off the power before the battery is fully discharged to extend the life. Despite this, many riders are still not fully discharged, and also use special chargers to finely control the charging speed and quantity, so that their batteries are full of vitality.
A more sophisticated battery management system will also monitor the temperature of the battery pack and trigger a power outage in the event of overheating.
If you are studying battery charging, you will most likely encounter C-rate. The C-rate describes how to quickly fully charge or discharge the battery. For example, a C-rate of 1C means the battery is fully charged within one hour, 2C means fully charged within 0.5 hours, and 0.5C means fully charged within two hours. If you use a 100 A battery with a current of 100 A·h to fully charge it, it will take 1 hour and the C-rate is 1C.
A typical lithium-ion battery can handle 300 to 500 charge/discharge cycles before the capacity is reduced. For an ordinary electric scooter, this is 3000 to 10 000 miles! Remember, “capacity reduction” does not mean “loss of all capacity”, but rather a significant drop of 10% to 20%, and it will continue to deteriorate.
Modern battery management systems help to extend the life of the battery, so you don’t have to worry too much about the baby’s use.
However, if you are passionate about maximizing battery life as much as possible, there are a few things you can do to exceed 500 cycles. These include:
Do not fully charge your scooter or plug it into the charger for a long time.
Do not store fully discharged electric scooters. Lithium-ion batteries will degrade when the voltage is lower than 2.5 V. Most manufacturers recommend storing the scooter at 50% power and charging it to this level regularly for long-term storage.
Do not operate the scooter battery at temperatures below 32 F° or above 113 F°.
Charge your scooter at a lower C rate, which means charging the battery at a lower rate relative to its maximum capacity to maintain/extend battery life. Charging at a C rate lower than 1 is the best. Some more advanced or high-speed chargers allow you to control this.
Learn more about how to charge electric scooters.
The main point here is not to abuse the battery, it will last the life of the scooter. We heard from all kinds of people that their electric scooters are broken, it is rarely a battery problem!
Frequently asked questions
How long can the electric scooter battery last?
Electric scooter batteries will last 2 to 4 years and 3000 to 5000 miles, depending on storage, usage conditions and battery capacity. If you use the scooter more or store it improperly, the battery life will be shortened.
How many times can the battery of an electric scooter be charged?
An electric scooter can go through 300 to 500 charging cycles before it starts to lose battery capacity. If it’s a baby, the highest quality brand battery can last more than 1000 recharge cycles.
How to maximize the battery life of electric scooters?
You can store the scooters charged to 50%, charge them at a C-rate lower than 1, and do not operate the scooters when it is too cold (below 32 F°) or too hot (above 114 F°), Thereby extending battery life.
When storing for a long time, make sure to charge the battery regularly. When storing for a long time, make sure to charge them regularly to prevent them from being completely discharged.
Can you replace the battery of the electric scooter? Is it worth the price?
Yes! You can replace the battery in the electric scooter, but it may not be cost-effective. The battery is one of the most expensive components of an electric scooter. Even a small 250 watt-hour battery, such as the M365 battery, costs about $150 or 1/3 of the cost of the entire scooter!
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