All about e-Bike battery fires

Everything you need to know about e-Bike battery fires

In the first 6 months of 2023 London Fire Brigade were called to an e-bike or electric scooter fire every two days. That's an increase of more than 60% over the previous year. Tragically, such fires have resulted in eight deaths and 190 people being injured in the UK alone. So what is behind this worrying trend? e-Bikes use lihtium ion batteries, the same technology as used your mobile phone, electric cars, and even pacemakers. When lithium ion batteries fail it can be attributed to three conditions:

  • Mechanical
  • Electrical
  • Thermal

Mechanical failure is physical damage to the battery and the cells that it's made up of. If you've crashed your e-bike then having a bike shop test it for damage should be at the top of your list before charging it. The battery may appear undamaged on the outside but internal damage can result in an electrical short circuit that will quickly lead to overheating. If there is bulging in the case of your battery then do not use it. This can be the result of flammable gases being released from the cells inside the battery.

Electrical failure is typically caused by overcharging. Using the correct charger for your e-bike is critical. Using the wrong charger can cause overheating that also results in the release of flammable gases from the battery cells. Combine the flammable gases with high heat and you have a fire that's not only difficult to extinguish but is also releasing toxins into the air you breathe.

Safely charging your e-bike

If all this has you questioning whether you should get rid of your e-bike, then don't worry. Although the number of e-bike battery fires has increased, it hasn't increased at the same rate as the number of e-bike users. Most fires have been the result of cheap, unbranded batteries, using the wrong charger, or people modfying their e-bike. The following steps are designed to ensure safe charging of your e-bike. Chances are you already follow them, but it's worth spending a couple of minutes to remind ourselves of the danger signs and things we can do to keep ourselves safe:

  • Only use the charger that is designed for your e-bike. If you've lost your charger replace it with the original manufacturer's charger rather than a generic one off eBay or Amazon.
  • Never charge your e-bike when you are asleep or out of the house. If something goes wrong you won't be there to stop it or, worse, you may never wake up.
  • If you have to charge an e-bike inside your home make sure it isn't blocking any exits.
  • Regularly check on your charging battery. Warning signs include excess heat (it's normal for batteries to get warm but not hot), bulging in the case, unsual hisssing or cracking sounds, smells or smoke. If any of these occurs disconnect the charger from the mains outlet immediately. If the battery is smoking or on fire, call 999 and leave the premises as soon as you have disconnected it from the mains. If you are unsure about the safety of your battery speak to the bike shop you bought it from.

The dangers of e-bike conversion kits

If you already own a bike it can seem like a good idea to buy a conversion kit and convert it to an e-bike. The problem is that many of the conversion kits available online use cheap, recycled batteries that do not meet UK safety standards. By law, in the UK an e-bike cannot have a motor more powerful than 250W. Some e-bike conversion kits are being offered with 20 times this amount of power. Interestingly, the website offering these kits will not fit them for you for legal reasons. Our advice is simple: stay away from conversion kits. Buying a pre-owned e-bike from a reputable dealer makes more sense economically. We have seen e-bike conversions that resulted in damage to the bike frame, such was the power being applied to it.

At iCycle we have been selling e-bikes since 2009. We partner with manufacturers that offer quality products and great value. Our workshop provides regular servicing, upgrades and repairs to all types of bikes and e-bikes. If you have any questions about e-bike safety we are happy to answer them. Simply call in or give us a call on 01772 347 927 or 01200 442 306.

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