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Thread: Best thing to do with flashlight if/when it goes critical?

  1. #1
    Join Date
    Apr 2003

    Default Best thing to do with flashlight if/when it goes critical?

    I was wondering, as I await the arrival of my L2i, which I plan to use with 18650's, what the best plan of action would be with a flashlight that you think is about to go nuclear.

    Putting your thumb on the tailcap to try to switch it off would be suicidal, since that is a weak area and one where the pressure may be released. Besides, once a cell has gone into thermal runaway, switching off the load won't do anything - correct?

    Throwing it away from you might work in an outdoors or other open area without a lot of people, but won't work in a crowded or enclosed area because of the potential for the light turning into a rocket, especially if the tailcap gives out.

    If it is a flashlight with one battery tube, would the best idea be to drop it to the ground and put your foot on the center of the battery tube, to stop it from moving with minimal danger to yourself or others? Of course, if you're indoors with a carpeted floor, that's a fire risk in itself.


  2. #2
    Join Date
    Apr 2004
    Lost In Space

    Default Re: Best thing to do with flashlight if/when it goes critical?

    depending on how alert you are the warning is a fair ammount of time. Just like your saying . . .

    1) switching off, If it Really is going thermal overrun, switching off at that point wont do nothing, dont bother it is to late. It either will disconnect itself and cool out, or it is going for it once it start Gassing , rumbling, vibrating. I dont want my apendages to be there, i can replace the house, re-growing a finger is much harder :-)

    2) throwing, if it was a false flag , and you toss the thing, you could damage the light and the batteries by tossing a perfectally good light :-) you could break something, or hit someone , better to just set it down, and wait for it to either do or not do. Even if outdoors, i cant think of how pannic and overreation could help.
    It is always best methods to be Prepared As you Are, and know before hand, then wild adrenilin filled reactions wont cause worse things to happen.

    3) What to Burn, Hmmm, tough one. i would not be stepping on it, i wouldnt be around it at all. if it goes, you dont want to breathe the fumes. and dont i need to get the fire extinguisher? Because after the solvent and lithium burn off, then i will need to put out the residual fire. Ok i might pannic still and try and put out the thing while the oxygenated fuel is still roaring :-) but then i guess i should get the other extinguisher just to be sure.
    Do you happen to have something that needs to be replaced anyway ? ugly stained carpet, linolium that should have been replaced last year , or floorboards that are pulling up :-) how about that ugly couch your wife forced you to buy ? :-)
    Last edited by VidPro; 03-18-2011 at 09:20 PM.

  3. #3

    Default Re: Best thing to do with flashlight if/when it goes critical?

    We has a SurefireZ12 go thermal on us , was standing vertcally on a shelf about 6 minutes after a quick "look" at it's picture , took off hit the ceiling and came to rest on the tile floor with a 18inch blow torch flame coming out of the bulb holder . The lens and bulb blew out which is good news as otherwise, I think we would have a hand grenade. . . I believe, especially 123 light manufacturers should make a weak point in the housing design for "controlled" venting to occur to minimize explosion risk. We were using some cheap Chinese 123's that seemed to have good burn times and handles the high draw P61 globes well. They worked well for about 18 months and then started going pop. We ended up tossing over a case of them. Just too risky to have around. The most expensive purchase you make is the one where you did not spend enough to get a happy product.
    I would suggest throwing the torch out of direct contact hopefully outdoors away from flamables. You don't want the fumes , possible explosion of flames near.

  4. #4

    Default Re: Best thing to do with flashlight if/when it goes critical?

    It happened to me once.... and that was enough. I grabbed the light and headed towards the bathroom to work under the sink. Just before I knelt down the flashlight got very hot. I quickly unscrewed the tailcap and put it in the sink. It cooled off. I threw the batteries away. I like to leave old (or damaged) batteries outside, on concrete or bricks, until trash day. I was lucky that I was holding the light and felt the heat! Had I put it under the sink and poked my head in....

  5. #5
    Flashaholic* shao.fu.tzer's Avatar
    Join Date
    Jul 2006
    P-Town, TX

    Default Re: Best thing to do with flashlight if/when it goes critical?

    I would probably do something similar to HotWire... If the tailcap doesn't take many revolutions to unscrew on that particular light, I would quickly uncap it and use the body of the light to fling the cells away from me. Some lights seem to take 21 forevers to unscrew so if I had one of those in my hand about to blow up, I'd probably set in on the floor and quickly run out of the room. If I didn't hear an explosion after a few seconds, I'd peek my head around the corner and look at it. If I saw flames and/or smoke, I'd then extinguish it with whatever I could find. Luckily this hasn't happened to me. To attest to the safety of LiFePo cells, I bought some Westinghouse branded 18500's that were on clearance at Wallyworld. After charging them up, I put a pair in. My light was nice and bright and I had no troubles. A couple of days later I went to swap them out with two freshly charged cells and I skipped my normal step of checking the cells with my multimeter since I figured they were supposed to be "safe" chemistry cells. I hit the switch and there was light but it was extremely dim. I swapped out the cells for 2 more, same thing. I figured my drop-in must have died so I showed my girlfriend and played with it a bit before unloading the cells to test them. It turns out two of the cells I tested were complete duds 0.00V reading on my multimeter (the two that made my light dim). The other 10 showed a perfect 3.35V with 0 deviation after sitting for about 2 days. But there was no explosion, venting, hissing, thermal runaway ..nada.. so I'm considering only using LiFePo whenever possible for my house and lender lights. I wouldn't want a lithium hand grenade to go off in my massage therapist old lady's hands and destroy her career.

  6. #6

    Default Re: Best thing to do with flashlight if/when it goes critical?

    Threads like this remind me why I only use primaries…

  7. #7

    Default Re: Best thing to do with flashlight if/when it goes critical?

    Quote Originally Posted by mhphoto View Post
    Threads like this remind me why I only use primaries…
    Sometimes it is the primaries that are to blame. Either user error such as mixing & matching new and partially depleted cells in a multi-cell light. Mixing & matching old and new cells. Or, as dbtrethewey mentioned above, using really cheap Made in China cells. Some things in Life you can cheap out on, and it's not going to be a big deal; most of the time. Some things . . . you just can't do that with. CR123 cells is one of those things.
    "The World is insane. With tiny spots of sanity, here and there... Not the other way around!" - John Cleese.

  8. #8
    Flashaholic bob4apple's Avatar
    Join Date
    Mar 2006
    Poughquag, NY

    Default Re: Best thing to do with flashlight if/when it goes critical?

    Quickly loan it to your in-laws.........
    When you die and go "into the light",
    don't complain about the tint!

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