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Thread: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

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    *Flashaholic* HKJ's Avatar
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    Default Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    Efest IMR26650 3500mAh (Purple) 2014



    Official specifications:
    • Typical capacity: 3500,Ah
    • Maximum discharge current: 32A
    • Maximum pulse discharge current: 64A
    • Maximum charge current: 6.5A
    • Resistance: 13mOhm +/-2mOhm
    • Nominal voltage: 3.8 volt
    • Discharge cut-off voltage: 2.5 volt
    • Full charge voltage: 4.2 volt
    • Temperature range: -20C ~ 60C
    • Temperature range discharge: -20C ~ 60C
    • Temperature range charge: 0C ~ 45C
    • Monthly self-discharge rage: <=0.5%




    A high current 26650 batteries, this time Efest has printed both the pulse and the continuous rating on the battery.










    The discharge curves is tracking nicely and capacity is nearly constant up to 20A and do also match the marked capacity. The 30A curve is a bit high for the battery.















    Conclusion

    It looks like this battery follows the Efest style for the purple batteries with very good high current performance. The price for this high current performance is less capacity.



    Notes and links

    The batteries was supplied by Efest for review.

    How is the test done and how to read the charts
    How is a protected LiIon battery constructed
    More about button top and flat top batteries
    Compare to 18650 and other batteries
    My website with battery, charger, usb reviews, comparisons & information: https://lygte-info.dk/
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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    Using your 26650 comparator, it is interesting to see that this Efest 3500mAh battery and the KeepPower IMR 4200mAh battery have almost equal voltage performance, up to a 10A load. But at 15A and 20A the Efest shows its superiority.

    Hopefully, Efest will send you a green IMR 4200MAh battery to test.
    Last edited by SubLGT; 12-03-2014 at 05:14 PM.

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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    Thanks a lot for your time and effort for doing this excellent review. HKJ!

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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    Great review - super informative, thanks.

    When they say


    • Maximum pulse discharge current: 64A


    How long is this pulse for? 1 second, or do they not say? If they don't say, isn't it meaningless?

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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    Quote Originally Posted by battery_bro View Post
    When they say


    • Maximum pulse discharge current: 64A


    How long is this pulse for? 1 second, or do they not say? If they don't say, isn't it meaningless?
    You are correct, the pulse specification is not complete, it is missing both on and off time.

    But drawing 60A might also be meaningless, a vaper drawing 60A might get less power into his atomizer than one drawing 30A.
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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    I got two of these when I bought my DQG Tiny Triple. Unfortunately I melted that light down and didn't even get to use for more than 120 seconds, lol.

    I think that the DQG TT pulls ~6A+ at the tail, so I wanted something with a bit more current handling that the other KKs, SupFires, green 5200s that M.E. had on hand and capacity wasn't a huge concert for me.

    Chris
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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    Quote Originally Posted by HKJ View Post
    You are correct, the pulse specification is not complete, it is missing both on and off time.

    But drawing 60A might also be meaningless, a vaper drawing 60A might get less power into his atomizer than one drawing 30A.
    Would watts be a more reasonable marker of performance? What do you believe is the ideal metric for a vaper, and what tool would be needed to perform that test?

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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    Quote Originally Posted by battery_bro View Post
    Would watts be a more reasonable marker of performance? What do you believe is the ideal metric for a vaper, and what tool would be needed to perform that test?
    Power is voltage*current, when using very low coil resistance you will get very low voltage and the higher current will not compensate for that. When going sub-ohmic all connections and the switch will also affect the result significantly.

    Without doing any test my guess would be: Look for around 2 volt directly across the coil for maximum power with a fresh LiIon battery. Anything less and you are probably not getting maximal power. A higher voltage will be better for the battery and give longer runtime.

    I do not know if you get the best kick with maximal power in the coil.
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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    I am getting a 26650 compatible flashlight but if I am running with that battery it solely for the purposes of having a lot more capacity than an 18650 might offer to allow for much longer running time. There aren't a lot to chose from in this size many are clearly false ratings by some manufacturers I have seen. Also for 18650 cell being rated to 6000 or 5000mAh. LOL

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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    Quote Originally Posted by tripplec View Post
    I am getting a 26650 compatible flashlight but if I am running with that battery it solely for the purposes of having a lot more capacity than an 18650 might offer to allow for much longer running time. There aren't a lot to chose from in this size many are clearly false ratings by some manufacturers I have seen. Also for 18650 cell being rated to 6000 or 5000mAh. LOL
    The Efest IMR 26650 is on the smaller size of the 'capacity scale' compared to some of the others available, like the KingKong 4000mAh and 4200mAh, or the newer green 5200mAh cells.

    Where you might want the IMRs, at least in my estimation, is if you have a 26650 like my now dead DQG Tiny Triple, that pulls (ed) 6+ amps, or more. The IMR chemistry might be better suited to that application. Same with the incan. hot wire guys, where they need a lot of juice, quickly.

    Chris
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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    @HKJ At what SOC and temperature do you perform your internal resistance tests? (it depends on both parameters)

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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    Quote Originally Posted by Gauss163 View Post
    @HKJ At what SOC and temperature do you perform your internal resistance tests? (it depends on both parameters)
    The SOC is about fully charged, it is done from the "Protection test" chart.
    The temperature varies a bit, at the current time it is probably around 22-25C, in the summer it might hit 30C, but is usual below 28C.
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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    Quote Originally Posted by ChrisGarrett View Post
    The Efest IMR 26650 is on the smaller size of the 'capacity scale' compared to some of the others available, like the KingKong 4000mAh and 4200mAh, or the newer green 5200mAh cells.

    Where you might want the IMRs, at least in my estimation, is if you have a 26650 like my now dead DQG Tiny Triple, that pulls (ed) 6+ amps, or more. The IMR chemistry might be better suited to that application. Same with the incan. hot wire guys, where they need a lot of juice, quickly.

    Chris
    Yes, the light I plan to use is both 18650 or 26650 compatible. However, if the 26650 is not a significant jump in mA then there is no point using them since there are a much wider cell as you know. I'd stick to 18650 and as my son says. Carry a pair of spares since its using two in series. The 26650's I have seen are very expensive in comparison but offer very little gain. Most no more that 1000mA more at best. That's nothing they should be in the 5000mAh ball park to be viable or even better given their size.

    I don't need the ultra high drain spec either. I am learning a bit more on these. I just got a new pair of Samsung 18650 cells "ICR18650-30B" 3000mAh. I'll use them when the light comes in and see how it holds up for runtime etc.

    OH I should have mentioned they took 10 WEEKS to come in from FASTTECH, absurd. I'll be buying others elsewhere next year somewhere else.
    Last edited by tripplec; 12-14-2014 at 08:22 AM.

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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    Quote Originally Posted by tripplec View Post
    However, if the 26650 is not a significant jump in mA then there is no point using them
    That depends, usual 26650 has higher voltage during discharge than 18650 (Especially high capacity 18650), in some lights this is a significant advantage.
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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    Quote Originally Posted by tripplec View Post
    …………...The 26650's I have seen are very expensive in comparison but offer very little gain………….
    The 26650 batteries I have seen and bought are very close in price to the 18650 batteries I have bought. If you use HKJ's battery comparator, you can see the significant performance gains that can be had with a 26650 versus a 18650.

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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    Quote Originally Posted by tripplec View Post
    The 26650's I have seen are very expensive in comparison but offer very little gain. Most no more that 1000mA more at best. That's nothing they should be in the 5000mAh ball park to be viable or even better given their size.
    You can get your 5000mAh 26650s, plus a little extra.

    And they aren't much more than 18650s...in fact, compared to Nitecore or Eagletac 18650s, among others, they cost LESS.

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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    I read about those Keepower cells but still more than a pair of good 18650. I haven't decide and not likely to with the Christmas season in full swing now. I also click over another year in a few days (birthday) so I'll have to charge my own batteries for the next year and keep on kicking....LOL

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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    A UK vendor has tested the Efest IMR purple 3500mAh against the newer Efest green 4200mAh version. The test is not as thorough as HKJ's testing, as it is only done at 35A.
    But the 4200 mAh version performed equally or better than the 3500mAh version.

    http://ukvapers.org/Thread-New-Efest-26650-batteries

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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    Here is a test, at around 8A, of the Efest purple 3500mAh versus 6 other 26650 batteries:
    http://vape-safe.blogspot.com/2015/0...mech-mods.html

    The Keepower 4200 IMR was the best performer, followed by the Efest purple.

  20. #20

    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    Quote Originally Posted by HKJ View Post
    Efest IMR26650 3500mAh (Purple) 2014



    Official specifications:
    • Typical capacity: 3500,Ah
    • Maximum discharge current: 32A
    • Maximum pulse discharge current: 64A
    • Maximum charge current: 6.5A
    • Resistance: 13mOhm +/-2mOhm
    • Nominal voltage: 3.8 volt
    • Discharge cut-off voltage: 2.5 volt
    • Full charge voltage: 4.2 volt
    • Temperature range: -20C ~ 60C
    • Temperature range discharge: -20C ~ 60C
    • Temperature range charge: 0C ~ 45C
    • Monthly self-discharge rage: <=0.5%




    A high current 26650 batteries, this time Efest has printed both the pulse and the continuous rating on the battery.










    The discharge curves is tracking nicely and capacity is nearly constant up to 20A and do also match the marked capacity. The 30A curve is a bit high for the battery.















    Conclusion

    It looks like this battery follows the Efest style for the purple batteries with very good high current performance. The price for this high current performance is less capacity.



    Notes and links

    The batteries was supplied by Efest for review.

    How is the test done and how to read the charts
    How is a protected LiIon battery constructed
    More about button top and flat top batteries
    Compare to 18650 and other batteries


    I have purchased 2 of these cells for an LED torch.
    I have found these cells completely self discharge, after a shout use, in about 4 days, not what I would expect.
    When fully charged they appear to have a greater self discharge rate that recorded in your review.

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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    Quote Originally Posted by Tony101 View Post
    [Excessive quoting of HKJ review removed]

    I have purchased 2 of these cells for an LED torch.
    I have found these cells completely self discharge, after a shout use, in about 4 days, not what I would expect.
    When fully charged they appear to have a greater self discharge rate that recorded in your review.
    That should never happen. However, it could be the cells or the torch.

    What kind of torch is it? Where did you buy the torch and the cells?
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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    I have two Efest IMR 26650 3500s that I got over a year ago to run with my DQG Tiny Triple that pulls 6A from the tail.

    They don't self discharge, they have decent capacity and I even had my first TT short out with one of my Efest cells and it didn't wreck anything, as far as I can tell.

    Maybe you got fakes?

    Chris

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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    Quote Originally Posted by Tony101 View Post
    I have purchased 2 of these cells for an LED torch.
    I have found these cells completely self discharge, after a shout use, in about 4 days, not what I would expect.
    When fully charged they appear to have a greater self discharge rate that recorded in your review.
    Could be a fake Efest cells, faulty cells or faulty flashlight

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    Default Re: Test/Review of Efest IMR26650 3500mAh (Purple) 2014

    I just purchased a Fenix PD40 that uses a 26650 battery to power a Cree MT-G2 LED; I will be using Keeppower 5200mAh batteries. I hope to find out if this combination will give me good performance in a weight to power to weight ratio and small size.

    My appreciation to HKJ and all those who make comments.

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