Chance of Runaway battery fire?

[Windward]

I have seen some disturbing video clips of runaway battery fires on e-bikes. Any guidance on best practice to reduce  chance of fire?


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[JimInPT]

I would buy only a battery pack that uses top-quality cells from Panasonic or Samsung, not some off-brand cheap Chineseium junk just to save money.

Then, don't drop, overheat or freeze it, keep it out of the weather when not in use, make sure the electrical contacts on the battery and the bike are protected when the battery is removed, don't make any electrical modifications unless you thoroughly understand what you're doing, and only use the OEM or high-quality aftermarket charger that understands these cells and can keep them properly balanced.  Even still, my charger is on a count-down timer that cuts power to the charger after 7 hours - don't forget about and leave a battery sitting on an operating charger indefinitely.

It would also be a good idea to inspect any exposed wiring if the bike has been dropped or otherwise mishandled; look for pinched, chafed or exposed wiring or connectors that can short out.

If you don't cut corners on the battery and charger, and use sensible precautions when handling and charging, I wouldn't worry too much.  Mass-produced quality batteries sold by reputable companies are well-designed, tested and capable of managing and protecting themselves pretty well.  But always respect the tremendous amount of electrical energy contained within - unleashing it all at once somehow is problematic, as seen in those videos.

[Altema]

Yep, good advice from Jim, and fires are very rare with good production batteries. I know one of the more famous fires in an elevator was actually an electric motorcycle, and the homemade battery pack was just laying in a steel tray that exposed the battery to moisture and impact.

I've got six batteries and have never had issues, but they are all Samsung or Panasonic, except for two which use Tesla cells. Three of them use the exact same charger (matching model number), so that simplifies charging.

[Windward]

Terrific guidance, thank you! I am going to put most of my battery rechargers on auto- turn off timers and will make sure i don't leave any rechargeable battery packs in the garage over the winter.