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Thread: Standard Alkaline AA vs. Lithium CR123A safety differences?

  1. #1
    Join Date
    Aug 2011

    Question Standard Alkaline AA vs. Lithium CR123A safety differences?

    I recently purchased a SureFire LX2 as a self-defense tool and was head over heels in love with it until I came across this forum which wised me up to the real dangers of the 123A cells it takes. After reading extensively on the safety of these batteries and viewing some really sobering photos, I've decided that it simply isn't worth the risk of a fire or explosion, especially since I planned on keeping right next to my head while I was sleeping.

    So, I'm returning the LX2 to where I bought it and am now looking for a safer flashlight with comparable output. I'm looking at the Fenix LD10 or LD20 now. But with all of the new information I've ingested regarding reverse charging, venting, highly toxic gasses, etc., I'm having a hard time sorting through what applies to standard alkaline batteries and what is specific to the lithium batteries.

    My specific questions are as follows:

    • Are standard, everyday AA alkaline batteries capable of producing the potentially violent explosions that the 123A can?
    • If the AA's do leak, is the material as hazardous as the 123's?
    • Do the AA's vent gases? If they do, would it build up as much pressure inside a flashlight as the 123's to the point where it essentially becomes a pipe bomb?
    • Is it likely for an AA battery to explode or catch fire if dropped or impacted?
    • If reverse charging does occur with an AA battery, would it result in the same consequences as the 123A battery?

    I know those are a lot of questions, but I want to be sure the chunk of metal filled with energy that I put next to me when I sleep is absolutely safe.

    Thanks so much - although this is my first post, I can't tell you how great of a resource CPF has been for me during the past month.

  2. #2
    Super Moderator
    DM51's Avatar
    Join Date
    Oct 2006
    Borg cube #51

    Default Re: Standard Alkaline AA vs. Lithium CR123A safety differences?

    Welcome to CPF, brightlights

    You'll come across some scary stories here, particularly in this sub-forum, but you need to bear in mind that for every story like that there are tens of thousands of lights like the LX2 in existence, with no such problems ever having occurred.

    It's a bit like flying, except with lights you have some control. As long as you replace both batteries at the same time with new, fully-charged ones of the same make, age and type, you'll be fine. That goes for Lithium, alkaline, NiMH, Li-Ion and any other cells used by CPF members.

    If that wasn't the case, SF and other manufacturers would have been sued out of existence long ago!
    Resistance is futile...

  3. #3
    Flashaholic* shao.fu.tzer's Avatar
    Join Date
    Jul 2006
    P-Town, TX

    Default Re: Standard Alkaline AA vs. Lithium CR123A safety differences?

    Just invest in a cheap battery tester and multimeter. I always group my primaries up by age, capacity, and voltage. I'm so paranoid that I recheck the cells every time I load a multi-cell light. When in the field, this isn't always possible, so that's why I group them first in case I don't have that luxury. I've been using multiple lithium cell lights regularly for something like 6 years now and have never had an explosion or venting of any kind. If you're really worried about it, use some LiFePo4s or IMR cells... they're much safer... Although I don't know if you can use those in an LX2...

  4. #4
    Silver Moderator
    SilverFox's Avatar
    Join Date
    Jan 2003
    Bellingham WA

    Default Re: Standard Alkaline AA vs. Lithium CR123A safety differences?

    Hello Brightlights,

    Welcome to CPF.

    To answer your questions...



    Yes they can vent gases and it is theoretically possible to have a sealed light that allows them to build up as with a diving light, but it is rare to experience an "explosion." If you open the light near a spark source you may get a small flare of flame. The gas in NiMh chemistry is hydrogen.


    No. Reverse charging NiMh just kills the cell.

    If you are concerned with CR123A cells you simply need to follow good practice and they will work very well. To be on the cautious side you would do a run time test to determine how long the cells last. Then you change cells and use them for half or two thirds of that time. This eliminates the problem of completely emptying the cells and running into reverse charge conditions.

    Doing that and only using quality cells will give you years of safe use.

    This is a little more expensive, but you have to ask yourself what your safety is worth.

    It also gives you the opportunity to purchase some single cell lights to use up your partially drained cells...

    Behind every Great man there's always a woman rolling her eyes...

    Most batteries don't die - they are tortured to near death, then murdered...

  5. #5
    Join Date
    Oct 2010
    Hong Kong

    Default Re: Standard Alkaline AA vs. Lithium CR123A safety differences?

    Despite these problems
    CR123A is actually safe if you dont misuse them
    Just becareful in:
    -NEVER charge it, even the charger says: suits primary lithium batts
    -Dont discharge in large current, it overheats it
    -Dont store in a hot environment
    -Dont burn it
    -Dont leave it under sunshine
    -Dont swallow it
    -Dont punture it
    -Dont disassemble it
    -Dont throw it
    -Dont short it
    -Dont use inferior cell which appears to be very cheap

    Enjoy your light

    I dont really agree with Question 2-No, depends on which situaton
    When CR123a leaks,
    1. Lithium perchlorate - Inert at room temperature
    2. Propylene carbonate - Inert
    3. Dimethoxyethane - Good ventilation get rid of em, hold your breath and move to a safer place

    AA leaks NaOH and its corrosive

    So i think it should be a tie
    Last edited by jh333233; 08-19-2011 at 03:30 PM.

  6. #6
    Join Date
    Sep 2011
    Somewhere in Hastings florida.

    Default Re: Standard Alkaline AA vs. Lithium CR123A safety differences?

    Aren't alkaline cells using KOH instead? That's what I always read here...alkalines I believe vent hydrogen as well (I believe the gas venting pushes out the electrolyte with it.)

  7. #7

    Default Re: Standard Alkaline AA vs. Lithium CR123A safety differences?

    Doesn't really matter if alkaline cells are using NaOH of KOH - VERY similar safety properties (i.e. corrosive, blinding if gets in eyes, very irritating to skin)

    I second using a multimeter if you have any doubt over the condition of your cells and only using matched groups together. If you do that and don't cook or short your cells you'll be fine.

  8. #8
    Join Date
    Aug 2006
    Waynesboro, Pa FM19es

    Default Re: Standard Alkaline AA vs. Lithium CR123A safety differences?

    The worst experience I had with Alkaline cells was in a VCR remote where I mixed two different cells with two different charge levels. I didn't use the VCR remote for several months and when I found that it didn't work I opened up the cover to find a large quantity of the inevitable white fuzzy stuff. I cleaned it out the best that I could and I still have the VCR and the remote (it still works). Back to the battery cells, The one cell literally split along the side. I didn't think about it again for several years until I started learning about Lithium battery safety here on CPF, ever since I have never mixed used cells of different charge levels regardless of the chemistry.

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