Single Cell Hazards

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CEHepp's picture
Last seen: 9 months 2 weeks ago
Joined: 03/23/2011 - 22:49
Posts: 503
Location: Charlotte, NC
Single Cell Hazards

I have done a lot of googling for the past few days and I can't find a single report of a single cell (mainly, single 18650) light explosion. Or even a single cell on a charger exploding. Does anyone here have any information on single cell dangers?

I did find an article on CPF stating that old batteries are going to kill everything they come near and should be discarded regularly but I don't see many reports of quality laptop packs going supercritical. How true is this statement?

I am researching because I keep my Zebralight on the stand next to my bed (and face) at night. I don't want to wake up with aluminum hanging out of the side of my head one morning.

Zebralight S6330 – Zebralight SC600w – Zebralight SC52 – Zebralight SC51w – EagleTac D25A Ti 219 – 4Sevens Quark Turbo AA2 219 – FourSevens Preon PenLight -

Edited by: CEHepp on 02/27/2012 - 19:09
trooplewis's picture
Last seen: 2 years 2 months ago
Joined: 03/26/2011 - 15:35
Posts: 2613
Location: San Diego

that's why I only own single-cell lights. Don't have the time or patience to worry about keeping them balance-charged or otherwise babying them.

Laptop have much more advanced electronic safeguards in terms of how the batteries are balanced and when/how much they are charged. Our cheap chinese lights (and chargers) don't have much in the way of protection.


Rats, finally sold my 2010 509hp I can buy more lights!

Sold the red one too! Now guess what I drive, doing my penance for 500 hp commuters...

Last seen: 8 months 2 weeks ago
Joined: 07/13/2011 - 16:18
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Location: Honeyland

Buy protected cells, when the voltage is too low the respective cell's protection circuit will trip and that's it.

Depending on the light you may have some sort of protection.  Respectable Jetbeam BC40 has no protection, will keep drain the cells, but flashlights like the Shadow TC6 will enter into strobe mode and will be practically useless when the voltage is low, or the JM07-Pro will start flashlight every two seconds, (Nanjg 105C driver with an 7135 chip removed )

Sefbuilt's reviews for example show perfect regulation, and perfect drop on many High branded lights, however he only uses protected cells. At one point one of the cells will trip the voltage protection or even both cells, that is the case of his Jetbeam BC40 review, from his review it looks like it would have a cut-off built-in but in fact it doesn't and with unprotected cells the light will drop to a low mode.

kbark's picture
Last seen: 8 months 2 weeks ago
Joined: 07/12/2011 - 13:22
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Location: North Carolina

I have a bunch of 18650s that I salvaged from laptop packs. I've tried to destroy several of them with no luck. Single cells seem to be pretty safe.

Chicago X
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One reason to not store cells in certain torches is the issue of standby, or parasitic current draw.

The current draw is often too low to trigger protected cells' low-V cutoff, driving the resting voltage too low to safely recharge.

Most electronically-switched lights have some standby current draw.

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