Nicola Rutzou
We regularly hear about house and apartment fires caused by e-bike or e-scooter batteries malfunctioning, and understandably, e-bike owners or potential buyers are concerned.
So, we thought it was time to investigate this serious issue and provide some reassurance that buying a reputable brand of e-bike is relatively safe.
In short, the main reasons batteries catch fire are overcharging, using a charger that doesn’t meet Australian Standards or doesn’t match the battery, excessive heat, damage, or a fault.
Last year, Fire and Rescue NSW reported 323 fires ignited by lithium-ion batteries, an increase from 272 fires in 2023 and 165 fires in 2022. Lithium-ion batteries are in many devices used in Australian homes, including smartphones, laptops, tablets, cordless power tools, robot vacuums, e-bikes, e-scooters, smartwatches, and many more. Most don’t cause house fires unless they malfunction.
Cheap, poorly made batteries and devices hold a higher risk of igniting.
In a report from the NSW Fire and Rescue (FRNSW) Lithium-Ion Battery Incidents report published in October 2024, it concluded:
- E-bikes used by delivery riders have caused fires on roadways, during charging, and where they have been stored, sold or serviced. They often involve replacement batteries that have a higher capacity or charging equipment selected to accelerate charging, resulting in greater fire risks. Of the 32 e-bike incidents, 22% occurred while being charged, and at least 25% involved high-capacity batteries.
- Twenty-eight per cent of the FRNSW recorded e-bike incidents in which batteries have been tampered with, repaired or replaced by both DIY enthusiasts and professional technicians.
What the manufacturers say
Speaking with reputable manufacturers like Trek and Bosch was very reassuring, as it provided insight into the standards both companies adhere to when manufacturing e-bikes and the components that go into them.
Krishna Menon, Product Marketing Manager for e-bikes at Trek, says that Trek’s e-bike batteries all include battery management software (BMS) that monitors the battery for excess charging and shuts off when it gets too hot.
“At Trek, we undertake third-party testing to ensure we meet the required standards. The company tests all our e-bikes and certifies them. Plus, we only work with suppliers that meet the same standards.
“That way, our bikes meet all international standards. This, of course, adds to the cost of the bikes, but we’re obsessive about quality and compliance,” added Menon.
“Our E-systems team constantly monitors international markets to ensure we meet all standards.”
As a consequence of this obsession with quality, Menon says that they have received no reports of Trek e-bikes being involved in fires.
“All our products include a long development process. We don’t constantly launch new products. That way, we can stand by all our products, including the frames and components on all Trek bikes.
“Our adherence to quality and standards also means we can confidently offer a two-year warranty on our e-systems,” concluded Menon.
Bosch is a leading manufacturer of e-bike systems, and has earned a reputation for its quality e-bike motors and batteries.
“At Bosch eBike Systems our priority lies on the safety and reliability of our products, and there is no shortcut when it comes to safety standards. This means that we apply safety standards related to the e-bike electrical system, which includes specific criteria to reduce the risk of fire, electric shock and mechanical hazards,” said a company spokesperson.
“In addition to our own tests, we also commission external third parties such as accredited testing laboratories to carry out tests and verify compliance with the standards, and we test some of the components beyond the standards.”
When asked about the systems Bosch has in place to minimise battery fires, they said “Batteries are complex, finely tuned systems with high energy content. When properly designed, manufactured, tested and used, lithium-ion batteries are a comparably safe technology. Some of the components can be flammable in certain rare conditions. We work closely with cell suppliers and have generated our know-how through testing to understand the potential causes of thermal runaway.
“A thermal runaway is caused by sudden temperature increase in the cells as an effect of overcharging, charging after deep discharge, short-circuit or external mechanical abuse/stress. Bosch has implemented mechanical and electrical measures to ensure that the batteries are protected in the best possible way from exposure to the events mentioned above that can trigger thermal runaway,” they said.
Regulations not keeping pace with e-bikes
Peter Bourke, General Manager of Bicycle Industries Australia (BIA), states that there are three types of regulations: import, bike, and usage.
He also notes that in Australia, we are adopting a fragmented state-based approach, with regulations being changed on the fly.
“In NSW alone, there are no less than 14 departments and agencies working on e-bike regulations. Plus, the industry is often not consulted when changes are made. Added to that, there is different legislation and definitions of an e-bike throughout the country,” added Bourke.
In February this year, the NSW Office of Fair Trading published a new Information Standard for the sale of e-bikes in NSW, and informed the BIA a week later. A summary of this and other standards in NSW can be found here.
Needless to say, it’s a highly complex area, and we won’t be trying to unravel it here. We’re glad there are people like Peter Bourke and the BIA working hard behind the scenes to help bicycle retailers and others understand their obligations.
“E-bikes and e-scooters are fantastic mobility solutions for many people in NSW, improving health, reducing congestion and harmful tailpipe emissions. In many cases, they are faster to get to work and school, and most importantly, they are fun.
“The vast majority of products on the market are safe, utilising similar battery cells to laptops and phones, and BIA supports the direction of government to ensure that all products meet the required quality standards,” concluded Bourke.
E-bike safety
Fire & Rescue NSW provides the following advice about charging an e-bike or e-scooter:
- If the charger didn’t come with the device or battery, don’t use it. Only use approved chargers to charge your battery.
- Just because the plug fits, it doesn’t mean it’s compatible.
- Only use chargers that show the Australian Regulatory Compliance Mark Tick.
- Charging a device or battery with the wrong power output (voltage and current) can cause damage to the battery and overheat it, which can cause a fire.
- Do not charge batteries when sleeping or not at home. Remember, you can’t smell smoke when you’re asleep.
- Once the battery is full, disconnect it from the charger.
- Don’t use and charge batteries that are swelling or bulging, leaking, or overheating.
So, to return to our original question – Are e-bike batteries safe? Yes, they are relatively safe, provided you purchase from reputable sources that sell high-quality products. We’re reassured by the lengths that brands like Trek and Bosch go to in order to keep us safe, and let’s face it, also to preserve their corporate reputations.
And here is some final advice from the NSW State Government.
