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Bench Test Results: iJoy 40A 3000mAh 20700 (4-“leg” version)...only 20A

Discussion in 'Batteries and Chargers' started by Mooch, Oct 18, 2017.

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  1. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    While the test results are hard data, the conclusions and recommendations I make based on these tests are only my personal opinion based on my criteria for setting a rating. Carefully research any cell you are considering using before purchasing.

    Testing cells at their limits is dangerous and should never, ever, be attempted by anyone who has not thoroughly studied the dangers involved and how to minimize them.

    If the cell has only one current rating number on it, or if it only says "max" then I have to assume that the company is stating that the cell can be discharged at that current level in any way, including continuously.

    Cell photos: https://imgur . com/a/735dC
    (Sorry for the split link but direct links to Imgur do not display properly)

    Bottom Line
    iJoy now has two versions of their “40A 3000mAh” 20700 battery, both in the same wrap. The original one has five “legs” coming down from the top contact and was rated at 30A 3000mAh by me.

    This newer version of the “40A 3000mAh” battery has four “legs” coming down from the top contact. Unfortunately it is a hugely overrated, poor performing battery.

    The voltage sag for this 4-leg cell version is a lot greater which results in about 30% less vaping time at moderate power levels (versus the 5-leg cell).

    While both versions of this cell are on the market now, and using the same wrap, iJoy has stated that they will be using a different wrap soon for the 4-leg version. iJoy has also stated that the 4-leg version will not be sold separately in the future and will only be included in their kits. The 5-leg version will continue to be sold separately.

    iJoy has also told me that they are working to lower the internal resistance of this cell. This will bring its performance closer to that of the 5-leg version. Once they release the updated 4-leg cell, with the new wraps, I will retest them.

    The white top ring insulator of this cell is card stock, i.e., paper, like the 5-leg version. It is quite thin though. Pay extra attention to the top of these cells if your charger is a tight fit or your mod damages cell wraps.

    I am rating this version of this iJoy cell at 20A and 2800mAh.

    The diameter of the 4-leg version ranged from 20.42mm - 20.49mm. This includes the distinct bumps at the seams of the wrap. Four cells were measured.

    The diameter of the 5-leg version ranged from 20.42mm to 20.48mm with five cells being measured. The 4-leg and 5-leg versions are essentially the same size.

    A note…the capacity rating of the 5-leg version will also be lowered by me (probably from 3000mAh to 2800mAh) as additional experience with these cells, and other 2x700’s with their different chemistry, has made me realize this change is needed. This will affect the Efest, EBAT, and Ampking 20700’s too as they also use the 5-leg version of this cell. Their performance has not changed, just the rating I am giving them. More info in another post.

    Several 4-leg cells were tested. I want to thank those who arranged to get samples of them to me, especially Evolution Vaping in the U.K. They expressed shipped cells to me here in New York City not once but twice after I realized I needed more cells to test. Thank you all!

    Continuous-Current Test Results
    iJoy 40A 3000mAh NEW 4-LEG CELL 20700 CC Tests for Capacity.png iJoy 40A 3000mAh NEW 4-LEG CELL 20700 CC Tests.png

    Pulse-Current Test Results
    iJoy 40A 3000mAh NEW 4-LEG CELL 20700 Pulse Tests.png iJoy 40A 3000mAh NEW 4-LEG CELL 20700 Pulse Tests ZOOMED.png

    Performance Comparison between the 4-leg and 5-leg Versions
    iJoy 40A 3000mAh NEW 4-LEG CELL 20700 CC Difference at 20A.png iJoy 40A 3000mAh NEW 4-LEG CELL 20700 Pulse Tests vs 5-leg.png

    iJoy’s statement regarding these cells

    At 10A continuous this cell delivered 2693mAh. This is terrible performance for a 3000mAh rated cell at 10A so I am rating it at 2800mAh.

    To see how other cells have tested and how hard you can safely push them, check out these links: List of Battery Tests | E-Cigarette Forum
    • Informative Informative x 5
    • Like Like x 3
  2. Rossum

    Rossum Surly Curmudgeon Verified Member ECF Veteran

    Supporting member
    Dec 14, 2013
    SW VA
    So despite the increase in size, no material advantage over some of the better 18650s available?
    • Like Like x 2
  3. sonicbomb

    sonicbomb Vaping Master Verified Member ECF Veteran

    Feb 17, 2015
    1187 Hundertwasser
    The old re-wrapper switcheroo stitchup ploy
    • Like Like x 1
  4. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    Runs cooler
    • Like Like x 4
  5. Gerrit van Asch

    Gerrit van Asch New Member

    Feb 16, 2018
    I brought a ijoy captain pd270 and it came with 2 of these cells, HOWEVER one is a 4 leg and one is a 5 leg? How safe are they to use together in the mod if they discharge at a slightly different rate?
  6. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    No battery use is completely safe. It’s all about risk reduction.
    As part of the risk reduction we can do I recommend not mixing batteries.
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