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Thread: M2T & shorter 18650 batteries

  1. #1
    Unenlightened
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    Default M2T & shorter 18650 batteries

    In the "Olight M2T Warrior Review" (2/10/2018 by rookiedaddy), he mentioned a problem with batteries less than 67mm long. To paraphrase what he wrote, with the shorter batteries there is room for the spring to compress and decompress. With the light on, if you shake or bump it slightly, the light could switch off.

    Has anyone experienced this problem, and tried solving it by using some sort of metal washer or spacer between the end of the battery and the spring, to essentially make the battery longer?

    Or would someone who knows a lot about about flashlight electronics like to venture a guess as to whether this would work?

    Thanks in advance for any replies.

  2. #2

    Default Re: M2T & shorter 18650 batteries

    I've owned and been using an M2T for over a year with no such problems. But then I don't go around using my light while shaking it back and forth to test it. I can't imagine why you would...but hey I haven't seen everything. I guess maybe you might need to use it as an impact weapon yet still keep it on...to light your target...anyway.

    I would think it was relatively clear. You add a conductive piece to the top that bridges the distance between the top of the shorter cell and the electrical contact on the tail switch. Just makes sure you insulate it to prevent it from shorting out between the cell top and the tube although in the specific case of the M2T, the tube interior is anodized. It does however have more than one contact inside the tailcap so shorting is still a concern.
    Last edited by lightfooted; 11-17-2019 at 05:40 AM.

  3. #3
    Unenlightened
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    Default Re: M2T & shorter 18650 batteries

    Thanks for the response. Not in law-enforcement, military, or emergency responder, so this is just for EDC and/or keeping in the car. So the shaking is just from unintended bumping, etc.

    Re your second point, that is very helpful. I have a Sanyo NCR18650GA 3500mAh High Discharge Flat Top I bought for my Zebralight SC63w, and it is 65.3 mm long. So maybe I won't have any problems using it in the M2T (haven't purchased yet). But if I do, I may try a small magnet, and figure out a way to insulate the cell top from the tube. I could try the 18650 PVC Wraps I previously bought with the Sanyo battery from Illumn.com.

  4. #4
    peter yetman's Avatar
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    Default Re: M2T & shorter 18650 batteries

    You can buy 18mm Aluminium washers on Ebay. I've stripped the existing wrapper off an unprotected cell and then rewrapped it with the washer in place at the negative end of the cell. It's a very useful fix, as the washers can be bought in various thicknesses.
    P
    "O frabjous day! Callooh! Callay!" He chortled in his joy.

  5. #5
    Unenlightened
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    Default Re: M2T & shorter 18650 batteries

    Thanks.

    When you rewrapped it, what did you rewrap it with? Do you think I could use electrical tape?

  6. #6
    peter yetman's Avatar
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    Default Re: M2T & shorter 18650 batteries

    You could, but just look on Amazon for "18650 shrink wrap".
    If you can find the stuff you cut to length yourself, you can be more adaptable.
    The shrink wrap makes a professional job. I use a fan heater to shrink the thing, it only takes 30 seconds.
    It's also useful to have some in the drawer for when you inevitably damage a wrapper.
    P
    "O frabjous day! Callooh! Callay!" He chortled in his joy.

  7. #7
    Enlightened Wonder's Avatar
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    Default Re: M2T & shorter 18650 batteries

    Keep in mind those shorter cells are unprotected. Since the light is made to run 2 CR123A's there is most likely no over discharge protection.
    Running unprotected cells will allow you to discharge the cells too far either making them unusable or possibly even dangerous.
    Protected 18650's have over discharge protection and is one of the main reason Olight recommends using them in all Li-ion compatible lights.
    Sure if you know what you are doing and always pay attention you can use unprotected cells. You can buy protected 18650's for under $10
    so why bother taking chances.

  8. #8
    Unenlightened
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    Default Re: M2T & shorter 18650 batteries

    Quote Originally Posted by peter yetman View Post
    You could, but just look on Amazon for "18650 shrink wrap".
    If you can find the stuff you cut to length yourself, you can be more adaptable.
    The shrink wrap makes a professional job. I use a fan heater to shrink the thing, it only takes 30 seconds.
    It's also useful to have some in the drawer for when you inevitably damage a wrapper.
    P
    I am lloking for shrink wrap to buy 2 metres do you know where can i find?

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