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How do I choose an ebike battery?

DJ Bikes knows the battery pack of your ebike is the most important component, so it is important to know what you are paying for and how your ebike will perform before making a purchase.

There are many questions commonly asked about the ebike batteries. In summary, users would like to know...

  • Power: How powerful is it?
  • Voltage: What voltage of battery should I purchase?
  • Safety: What certifications should a lithium battery have?
  • Life Span: How long does the battery last?

 Power

Speaking of power, we need to understand the math behind it. The unit Watt-hour (Wh) is the power rating of your ebike battery. The battery determines how long your bike will go. How does the motor relate to your battery? Let me give you two examples:

1. If you own an ebike with a 250 watt motor and a 250 Watt-hours (Wh) battery, the battery will last you an hour (250/250) at full throttle. However, the low 250 Wh battery will not give you much pedal assist.

2. If you upgrade your ebike with a 500 watt motor and a 625 Watt-hours (Wh) battery, at full throttle the battery will last 1.25 (625/500) hour, and you will be given twice as much boost as you get from the 250 watt motor.

Therefore, a high Watt-hours battery gives you a longer range, but comes with a higher price.

 Voltage

In general, you want to choose a higher amp battery over a lower amp battery. You will not damage your controller with a high amperage battery, however, picking the wrong voltage battery can do serious damage to your ebike motor and controller. Get the voltage right and you can’t go wrong with the rest.

 Safety

A lithium battery in the US and Canada is considered as HazMat ( Hazardous Material) and usually requires certification to be able to travel safely. The HazMat certification is UN38.3, governed by United Nations.

Beside that, all lithium batteries need to pass a series of physical and electrical tests to endorse the battery performance. These tests include Cell Balancing , Over-Discharge & Over-Current Protection, Free Fall and Temperature tests.

A lithium battery charger also needs to be UL certified to comply with the US quality standard. We have seen many no-name chargers without any certification on the market.

We also want to introduce you to another ebike component. A speed controller limits the top speed of your pedal assisted ebike. In the US and Canada, electric bikes must not employ motor assistance at speeds over 20 miles/h and 32 km/h on level ground. Therefore, your ebike is safe to ride with the speed controller.

 Life Span

We suggest going for a good brand battery such as Samsung and Panasonic Lithium Battery, which will last longer in a number of charge cycles. These good brand batteries will usually have the lifespan of 500+ charge cycles. If you are a frequent bike rider then the battery will last 2-3 years.

Here is the list of tips we would recommend you to do to extend your ebike battery lifespan:

  • Always turn your battery key “OFF” after each use.
  • Charge the battery frequently. If possible, before using 50% of the power.
  • When starting from a dead stop, use the pedals to bring the bike up to speed.
  • When riding uphill or against the wind, pedal to supplement the battery power.
  • Avoid riding your bike in heavy rainstorms, thundershowers or extreme weather conditions.
  • Store your battery in a location with a temperature above 50°F/10°C.

You can buy batteries directly from DJ Bikes to ensure a compatible fit with your DJ Bike, and you can find your Battery FAQs answered in our Knowledge Base.

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