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Thread: 21700 protected charger

  1. #1

    Default 21700 protected charger

    Hi I am looking for a charger that can handle 21700 protected cells. I would like to get something with a nice display and some decent battery info and analyzing ability. I would like something 4 cell as well. I was looking at the VP4 Dragon but it seems it won't handle 21700 protected cells. I am looking to get a new flashlight and have been liking the Fenix PD36r and it comes with a 21700 protected battery and I know the flashlight can charge it but I would like to have more than one battery and having them charged and ready would be nice. I understand I could get non protected batteries but then that means I will always have to charge the battery that came with the flashlight in the flashlight and would like to just have a charger that just does them all. That also brings up the question do many of you recommend protected over non protected batteries for flashlights? I have a nitecore p12gt right now and have been using non protected 18650s with that fine but that is only because I had those batteries from when I was vaping and they worked. I like the idea of the longer run times with the 21700 cells. But it seems very hard to find one of the nicer chargers that can fit the protected cells. Any recommendations would be great.

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  2. #2
    *Flashaholic* BVH's Avatar
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    Default Re: 21700 protected charger

    The SKYRC 3000 has all the features you ask for and more. My 21700 unprotected cell is about 2.762" long measured with digital calipers. When I pull back the movable charger contact to maximum, there is about .020-.025" clearance to get a slightly longer battery in. So if your protected battery is about 2.780", it would fit in the SKYRC 3000 charger. 2.780" = 70.612mm so larger opening than 70mm cell. I used a double layer of paper on both ends of the cell to insulate the calipers from shorting the cell, then subtracted the thickness of the paper. Be careful when measuring.
    Last edited by BVH; 07-12-2020 at 02:47 PM.
    WWII 60" Carbon Arc (Sold), 1.6KW NightSun, 1KW VSS-3A, .8KW TrakkaBeam, 600W M-134 Light, 500W X-500-14s, 500W Starburst, 500W A120b, 450 Watt AEG German Leopard 1 Tank Light, 300W Locators, Megaray, 150W Communicator, Maxabeam Gen3, Syniosbeam by Enderman

  3. #3

    Default Re: 21700 protected charger

    Quote Originally Posted by BVH View Post
    The SKYRC 3000 has all the features you ask for and more. My 21700 unprotected cell is about 2.762" long measured with digital calipers. When I pull back the movable charger contact to maximum, there is about .020-.025" clearance to get a slightly longer battery in. So if your protected battery is about 2.780", it would fit in the SKYRC 3000 charger. 2.780" = 70.612mm so larger opening than 70mm cell. I used a double layer of paper to insulate the calipers from shorting the cell, then subtracted the thickness of the paper. Be careful when measuring.
    According to the specs on the Fenix 21700 that comes with the PD36R it is 2.99" long so sounds like it won't fit in the SKYRC3000.

    I have been looking at the nitecore ums4 too but not sure if it is as nice but it would definitely fit the batteries.

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  4. #4
    *Flashaholic* BVH's Avatar
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    Default Re: 21700 protected charger

    WOW! That seems like a very long 21700. It's basically a 75mm cell. Doesn't seem reasonable that a protection board would add around 5mm or almost 1/4" inch. Maybe try to get someone who's selling the light you want to measure the actual battery.
    WWII 60" Carbon Arc (Sold), 1.6KW NightSun, 1KW VSS-3A, .8KW TrakkaBeam, 600W M-134 Light, 500W X-500-14s, 500W Starburst, 500W A120b, 450 Watt AEG German Leopard 1 Tank Light, 300W Locators, Megaray, 150W Communicator, Maxabeam Gen3, Syniosbeam by Enderman

  5. #5

    Default Re: 21700 protected charger

    I thought it seemed like a pretty long battery too. I am going to order the light and will see just how long it is.

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  6. #6

    Default Re: 21700 protected charger

    Quote Originally Posted by BVH View Post
    WOW! That seems like a very long 21700. It's basically a 75mm cell. Doesn't seem reasonable that a protection board would add around 5mm or almost 1/4" inch. Maybe try to get someone who's selling the light you want to measure the actual battery.
    So I have done some more research and it seems that most protected 21700 batteries are about 75mm long and the protection circuit does add 5mm. I am not opposed to using unprotected cells at all. I mean I have been with my current 18650 light and it seems as long as you are safe with them and don't over charge them or overload them you are fine. So it seems with a good light that has built in protection in the light and a quality charger I really wouldn't need protected cells. So I would have the one that came with the light that I could only charge in the flashlight but could more unprotected cells than protected cells for the $. I am thinking I might either try to sell the new unused cell that comes with the light and order some good unprotected cells to use with it and a good charger. Is the Skyrc really worth the extra $ over the VP4 Dragon? Also what 21700 cells do people recommend? They would have to be button top for this light.

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