How safe are Lithium batteries in e-bikes etc ?

MouldyOldDough

I keep on seeing articles about house fires "caused" by lithium batteries in e-bikes - but further down the page, it generally says "modified or home made".

How many fires are caused by OEM Batteries in standard / Unmodded OEM bikes/wheelchairs etc ?

Neil_Jones

All batteries (OEM or otherwise) if they're overcharged are a fire risk. Its the heat of an overcharged battery reacting with the chemical make-up of the battery that causes the fire, not the battery itself (not directly anyway), in a process called thermal runaway. Basically one cell fails, and the adjacent ones fail not far behind in a chain reaction. In a worse case scenario in a confined space you get a flammable vapour cloud, that can be set off by sparks from the failed cells and that causes your house fire.

https://www.britsafe.org/safety-management/2024/lithium-ion-batteries-a-growing-fire-risk might be of interest.

flaneurs_lobster

Home-made lithium batteries? Really?

Bet those figures for fires caused by dodgy cheap third-party batteries are hard to come by, what would you say when asked the question on the house insurance claim form?

MyRealNameToo

Depends what you mean OEM, most the "modified" isnt the electric kit thats been modified but an electric kit fitted to a bike. Unsurprisingly these can be bought much cheaper of certain far east websites but naturally there is no guarantee as to what safety standards these have been built to. These are technically OEM so are you including these or not?

The other issue often pointed to is buying cheap chargers off similar sites, a double issue if the battery is also from there as either or both may not have the standard protections you'd have in an item made to UK/EU safety standards.

Most the fires are likely to have come from converted bikes, according to the OPSS of all the fires involving e-bikes in 2022 about 46% were converted bikes 4% bikes manufactured as an e-bike and the remainder were "unknown". In the same time frame there was a 1 electric wheelchair fire and 1 mobility scooter.

It's difficult to know the numbers of each in the UK to say if the 3 manufactured e-bike fires is materially higher rate than the 1 wheelchair fire. There was also no comment in the report if the owners had tried to modify the 3 manufactured bikes

MouldyOldDough

https://forums.moneysavingexpert.com/discussion/comment/81886430#Comment_81886430

I did not say that - as you are well aware - I was talking about HOME MADE / MODIFIED E-BIKES etc using lithium batteries from an unknown source……..

forgotmyname

Unlikely to find real data on the brand charge rate and quality of the battery packs used whether factory
units or DIY made.

Just look at all the battery recalls from big brand battery manufacturers, there have been many.
were they recalled as a precaution or a genuine high risk of failure?

flaneurs_lobster

https://forums.moneysavingexpert.com/discussion/comment/81887883#Comment_81887883

Ah, yes, can see that now.

Must stop speed-reading these posts.