Electric bike conversion kit batteries: what you need to know

Media scare stories about fires and worries about the longevity of previous battery types can put people off electric bikes. These days, there’s no reason to worry as long as you’re buying quality kit.



A modern lithium bike battery functions much like a mobile phone one and over time the maximum range will slowly decrease. Boost batteries will, however, hold 80% of their charge for at least 18 months. You don’t need to fully discharge the battery after each ride.

Charge cycle

As the battery charge runs out each time, the amount of power it outputs will gradually fall. For about the first third of its charge, you’ll accelerate easily when you start to pedal and find it easy to go uphill. In the next third, you’ll still definitely appreciate the assistance but it won’t feel quite as good as when fully charged. In the last third, it can feel a little sluggish. This change is due to the chemical performance of Lithium batteries. 

Cold weather

You will notice that in the winter, when it’s cold, range will be reduced. Again, this is true of all Lithium batteries, which use chemical reactions to provide the power. 


The Boost kit’s battery is easily removable, so you can take it with you to charge it. You can also buy an additional battery to double the range. 

Bike theft is an ongoing issue in the UK - being able to remove the battery reduces the attractiveness of your bike to thieves. Not only can they not tell it’s now an ebike, they won’t get any assistance if they steal it.


The London fire brigade recently put out a statement on lithium battery fires saying: “Cheaper batteries purchased from online sources which don’t necessarily adhere to UK safety regulations are more likely to fail and cause a fire” and recommending bike conversion kits are bought from a reputable seller.

We endorse this message. Our batteries include safety mechanisms such as gas valves and a battery management system. And we recommend that users use a bike shop to fit the kit if they aren’t comfortable doing so themselves. 

In general, lithium batteries are used successfully on millions of products. As long as you take care of your battery, we’re confident you’ll have no problems. Make sure you:

  • Use the right charger
  • Let the battery cool before charging it
  • Inspect it occasionally for damage