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A comment on Fire hazard of WHY2025 badge due to 18650 Li-Ion cells.

Re:Fire hazard of WHY2025 badge due to 18650 Li-Ion cells by aetherspawn on Friday August 08, 2025 @09:56PM (#44843437)
Lithium is the wrong chemistry for this novelty throwaway thing. Risks of fire all along the supply and disposal chain.

They could just use a few watch cells. LEDs use no power at all, so lithium not required; and watch cells aren’t hazardous when shorted.

Even the form factor of 18650 seems wrong for this, they would be so bulky compared to watch cells or AAA cells.

[ Parent | on HN ]
Re:Fire hazard of WHY2025 badge due to 18650 Li-Ion cells by stonogo on Friday August 08, 2025 @10:52PM (#44843689)
Watch cells are also usually lithium. I'd have just gone with LiFePO4 18650 cells.
[ Parent | on HN ]
Re:Fire hazard of WHY2025 badge due to 18650 Li-Ion cells by amluto on Saturday August 09, 2025 @01:04AM (#44844148)
Huh? A little CR2032 or similar cell has minimal short circuit current. A LiFePO4 18650 may not set itself on fire if shorted, but it could still set the rest of the badge or your shirt on fire.
[ Parent | on HN ]
Re:Fire hazard of WHY2025 badge due to 18650 Li-Ion cells by aetherspawn on Saturday August 09, 2025 @01:04AM (#44844149)
That doesn’t solve the issue because the fire risk is due to short circuit. Any battery that is Li-based has too low IR to self limit.
[ Parent | on HN ]
Re:Fire hazard of WHY2025 badge due to 18650 Li-Ion cells by mfitzp on Tuesday August 12, 2025 @02:46PM (#44880276)
The “badge” has a 2.8'' TFT screen, not just a couple of LEDs.
[ Parent | on HN ]