Lithium-ion Battery Pack For Electric Bike

Lithium-ion Battery Pack For Electric Bike E-Bike

Are E-Bike Batteries Universal and Interchangeable?

Traveling fast and far (and having fun) on your e-bike is hugely dependent upon your electric bike battery. The battery can make or break the electric bike experience. So what should you do if you need a new battery or your battery has lost its charge (and what if you’re far from home)? Can you put any battery on your e-bike as long as it seems to fit?

Unfortunately, e-bike batteries are not universal or interchangeable. An electric bike requires a specific type of battery based on its voltage (V), amps/capacity (Ah), and other features such as size and weight. For example, you can’t put a 48-Volt battery on an e-bike built for a 36-Volt one.

The biggest mistake you can make about e-bike batteries is believing that they’re all the same… even though they look similar.

But this is far from the truth! If you’re trying to replace the battery in your e-bike, you’ll need to make sure you get one that has the correct specifications. Otherwise, your bike either won’t work or you’ll cause serious damage to the battery and motor.

Why Aren’t E-Bike Batteries Universal?

Having one universal battery for all types of electric bikes is certainly ideal. Wouldn’t it be nice to just grab an emergency battery anywhere they sold electric bike batteries? You wouldn’t have to be worried about your battery dying while you were riding because you could pick up a new one in a pinch. And you could even borrow a battery from another e-bike for the day.

Unfortunately, this isn’t how it works. There are so many different kinds of lithium-ion batteries, all with unique specifications. They may differ in voltage (V), capacity (Ah), energy/watt-hours (Wh), size, and weight.

For a quick understanding, what’s ultimately important to know is that Voltage x Amp-hours= Total Watt-hours. Therefore, a battery with a different amount of volts or amps would produce totally different Watt-hours. Further, the volts and amp-hours must not only match the battery charger you’re using (generally the one that comes with the battery) but also the total wattage of the e-bike itself.

For example, a 48V lithium-ion battery may already be slightly larger and heavier than a 36V lithium-ion battery. And, even if it had the same amp-hours as the 36V bike, it still wouldn’t give out the same Watt-hours. And, there are several other potential problems as well that can be answered by understanding what voltage and amp-hours are best for your e-bike.

What Voltage is Best for an Electric Bike?

Generally, an average voltage (V) for e-bike batteries is 36 volts. This is because the maximum speed of an average human pedaling is around 20 km/h (12 mph). So, a 36-volt battery will help maintain a reasonable and safe speed for someone riding an e-bike. Depending on where you live, a manufacturer is required to follow laws about how fast an electric bike can go… and some laws set maximum speed limits for an electric bike.

However, more and more electric bikes are using a 48-volt battery (in places that the law allows higher speeds, like in the US), especially on higher-performance bikes and/or e-bikes that have a throttle. Why? Because bike riders want more speed!

Let’s not get confused about higher voltage meaning more power (at least not on its own). By itself, higher voltage just offers higher speeds.

But, if you use a battery with a higher voltage than your electric bike needs, it runs the risk of overcharging and may stop working sooner than usual. This is a really good example of why e-bike batteries aren’t universal.

What is in an electric bike battery?

A typical lithium-ion electric bike battery is comprised of two main components – the individual lithium-ion cells and the battery management system.

18650-format Cells
These cells are slightly larger than an AA battery and are named due to their size of 18mm x 65mm. They are used in high-drain devices due to their superior capacity and discharge rates.

Typically these cells will have an average voltage of 3.7v and around 3000-mAh capacity. These cells are then combined in parallel (to increase capacity Ah) and series (to increase Voltage) to create a larger battery suitable for the higher power demand of an electric bike motor.

For example, in a common 48V / 15-Ah pack there would be a total of 65 cells (3.7v, 3000 mAh). These 65 cells would be combined in parallel in groups of 5 to get 15 Ah (3Ah x 5 cells), and these 13 groups of the 3.7v packs would be combined in series to get a nominal 48 V (13 x 3.7v).

Battery Management System (BMS)
The battery management system is the ‘brains’ of the battery, which helps keep the individual sub-packs within a larger battery well balanced to improve the longevity of the battery. It helps with charging (limiting the amount of current) and discharging by limiting the number of amps that can be drawn out of the pack.

Some BMS can also monitor for higher temperatures and limit the battery to prevent overheating and damage to the cells. Some can also connect to your phone via Bluetooth to provide more detailed battery information and have an on/off switch for the battery.

JB BATTERY has over 10years on electric bike battery experiences: Lithium-ion (li-ion) battery packs are the best option for electric bike.

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