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Thread: 18650 for infrequent use?

  1. #1

    Default 18650 for infrequent use?

    Have a super bright, well made light that uses 4x18650 (Thorfire S1). Great light. But I hardly ever need to use it anymore. What are some good options for batteries here? Are they cr123 adapters? I'd imagine even IF 18650 primaries are out there they cost an arm and a leg... Right now I just have some laptop battery pack 18650's because I haven't wanted to spend the money for some nice AW's that will never get used (although the AW rcr123's in my bedside light have held up great over too many years!).

  2. #2
    Enlightened
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    Default Re: 18650 for infrequent use?

    Just make sure you use cells from a good company, keep the light stored someplace that doesn't get too hot, and don't keep topping off the cells so often that they are at full charge constantly. I had some AW RCR123s that saw light use (several dozen charge cycles in the 1st few years), were topped off maybe once a year or so if not used, and they were still good after 10 years.

  3. #3
    Flashaholic* ChrisGarrett's Avatar
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    Default Re: 18650 for infrequent use?

    Quote Originally Posted by Buck91 View Post
    Have a super bright, well made light that uses 4x18650 (Thorfire S1). Great light. But I hardly ever need to use it anymore. What are some good options for batteries here? Are they cr123 adapters? I'd imagine even IF 18650 primaries are out there they cost an arm and a leg... Right now I just have some laptop battery pack 18650's because I haven't wanted to spend the money for some nice AW's that will never get used (although the AW rcr123's in my bedside light have held up great over too many years!).
    Just discharge your 18650s down to ~3.6v-3.7v, place them in a plastic case(s) and then put them into a ZipLock baggie. Place them in your fridge. I have about 40 various sizes in my fridge right now, just because I don't use my stuff all that often.

    I don't know of any 18650 primaries, but I'll never say never.

    Be careful of using laptop pulls in high drain lights, as they get beaten up over use and 'might' be a bit tired.

    Chris
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    Default Re: 18650 for infrequent use?

    Decent cells can be had for a little over $5 each, if you charge them to around 3.9v , heck even 4v!. Then you can lock out your light(accidental activation/parasitic drain stopped if applicable) by undoing tail cap or head a little to break contact. Then if/when you do need the light, you have it at the ready with enough juice. This is without leaving the 4 cells fully charged for months.........year/s which can shorten their life.

    Just a thought...........

  5. #5

    Default Re: 18650 for infrequent use?

    I have a cheap kootek light in my car with an unknown HYY brand 2200mah 18650 in it. I charge it 2-3 times a year to full charge and itís left on full all year in the car. From hot summer to -25F. Lowest itís been is 4.16 in three years and the light always runs when needed. I donít. See any reason why just about any 18650 wouldnít serve adequately. That cell has endured seasons worth of extremes of temperatures with no noticeable ill effects.

    I wouldnt even worry about it. Just charge them up and check every 4-6 months and top off if they are too low. If mine were to go bad Iíd consider the three years honorable service. As it is it looks like Iíve got much more time left on it and itís still got the worst of winter to go through and Iíll check it when things start to get warm again. Itís been used a few times and it will be used a few more until then.

  6. #6
    Flashaholic*
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    Default Re: 18650 for infrequent use?

    Yes, you can leave a lithium-ion battery fully charged, and it will hold that charge quite well. However, it will also lose total capacity. If you don't mind replacing the battery every 2-3 years, or don't mind short run-times if you choose to keep using the old cell, then don't worry about it. Otherwise, charging to 3.9v or 4.0v is a good suggestion, since that will greatly reduce the capacity loss.

  7. #7

    Default Re: 18650 for infrequent use?

    Quote Originally Posted by Boris74 View Post
    I have a cheap kootek light in my car with an unknown HYY brand 2200mah 18650 in it. I charge it 2-3 times a year to full charge and itís left on full all year in the car. From hot summer to -25F. Lowest itís been is 4.16 in three years and the light always runs when needed. I donít. See any reason why just about any 18650 wouldnít serve adequately. That cell has endured seasons worth of extremes of temperatures with no noticeable ill effects.
    I've done the same and experienced the same small drop in voltage. But that's the not problem. The unnoticeable effects are what's hurting the battery. The internal resistance will be ski-high after being charged and going thru those temp extremes. The DMM may read 4.16v, the light will power on just fine, but it's not necessarily a "healthy" battery. Not something you want to rely on.
    GOOD TINT!

  8. #8

    Default Re: 18650 for infrequent use?

    Quote Originally Posted by WalkIntoTheLight View Post
    Yes, you can leave a lithium-ion battery fully charged, and it will hold that charge quite well. However, it will also lose total capacity. If you don't mind replacing the battery every 2-3 years, or don't mind short run-times if you choose to keep using the old cell, then don't worry about it. Otherwise, charging to 3.9v or 4.0v is a good suggestion, since that will greatly reduce the capacity loss.
    I've seen data for NMC/INR batteries (Sanyo UR18650E) and NCA (Panasonic NCR18650PD) suggesting in the ballpark of 6-7% capacity loss per year if stored at full charge and at room temperature, and maybe 3% if stored at half charge. There is a step change somewhere around 60% state of charge, so if you want to take advantage of this knowledge, the big gain comes at a resting voltage somewhere around 3.7V.

    Keep in mind state of charge doesn't correlate perfectly with voltage, and this is only a test of a one model each of two chemistries. This also is based on a 10 month long test project, so it's possible the rate of capacity loss accelerates or slows over time.

    Either way, I'd expect more than 2-3 years of useful life out of most cells. Hopefully 5+ years, even for cells placed into storage fully charged and ~10 years if stored half charged. The effect is more pronounced at high temperature, both on capacity and internal resistance.

    Fortunately, a half-charged 18650 battery still is pretty useful. If you're not using the light often, you might not even need the full capacity anyways. If it's not a ready light that you might need to use for an extended period of time unexpectedly, meaning you'll have the chance to charge before heavy use, storing half charged is a great strategy.

    It is wise, however, to check the batteries once a year to make sure they're staying above 3V, and to unscrew the tailcap of lights with electronic buttons instead of clicky switches if you're storing the batteries in the light.

  9. #9
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    Default Re: 18650 for infrequent use?

    Quote Originally Posted by iamlucky13 View Post
    Either way, I'd expect more than 2-3 years of useful life out of most cells. Hopefully 5+ years, even for cells placed into storage fully charged and ~10 years if stored half charged. The effect is more pronounced at high temperature, both on capacity and internal resistance.
    Yes, but in the OP's case, he's wanting to store them in a car where temperatures can get very high in summer. I think the capacity loss will be greatly accelerated in that case. But, you could be right and they'll last longer than 2-3 years. I just guessed at that figure, based on how 18650 batteries perform in laptops, where they're kept fully charged and often warm. I don't usually get more than a couple of years from a laptop battery, before it's noticeably suffering from loss of capacity.

  10. #10

    Default Re: 18650 for infrequent use?

    Still havenít found anything like a cr123 primary to 18650 adapter. Does anybody know of an option?

  11. #11
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    Default Re: 18650 for infrequent use?

    Quote Originally Posted by Buck91 View Post
    Still havenít found anything like a cr123 primary to 18650 adapter. Does anybody know of an option?
    Wouldn't the voltage be rather low, for a light designed to run on a 4.2v cell? You might find lvp kicking in as soon as you turn on your light.

  12. #12

    Default Re: 18650 for infrequent use?

    Quote Originally Posted by WalkIntoTheLight View Post
    Wouldn't the voltage be rather low, for a light designed to run on a 4.2v cell? You might find lvp kicking in as soon as you turn on your light.
    An 18650 sized adapter, containing a small buck driver and two CR123 batteries in series.
    That would be a neat project; find a source for thin walled plastic tube of the right diameter and thickness, and a small, cheap buck driver, and it would be nearly done.
    Last edited by eh4; 02-13-2018 at 10:23 AM.
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  13. #13
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    Default Re: 18650 for infrequent use?

    Quote Originally Posted by eh4 View Post
    An 18650 sized adapter, containing a small buck driver and two CR123 batteries in series.
    That would be a neat project; find a source for thin walled plastic tube of the right diameter and thickness, and a small, cheap buck driver, and it would be nearly done.
    You couldn't fit two CR123 cells in a 18650 tube. Might be able to do it with a single CR123 and a boost driver, though.

    It would be purely for fun. For practicality, if you need to use lithium-primaries for cold tolerance, just get a CR123 light. Or a AA light and use energizer lithiums.

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