LG HE4 20A 2500mAh 18650 Bench Retest Results...a good 20A battery but 25R5 is better

Discussion in 'Batteries and Chargers' started by Mooch, Mar 6, 2016.

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  1. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    These cells were purchased for testing with donations made for that reason. Thank you! To prevent any confusion with the eGo-type "batteries", I use the term "cell" here to refer to a single 18650, 26650, etc.


    Disclaimer
    The statements, conclusions, and recommendations I make based on these tests are only my personal opinion. Carefully research any battery 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.


    A note regarding current ratings and my testing
    If the cell has only one current rating number on it, or if it says "max discharging current", then I have to assume that the company is stating that the cell can be discharged at that current level in any way, including continuous.

    image.jpeg image.jpeg image.jpeg image.jpeg


    Bottom Line
    While this is a good 20A continuous battery it delivers about 11% less capacity than the Samsung 25R5 at 20A down to 3.2V. Its pulse performance is just a bit below the 25R5's and the HE4 runs a few degrees hotter. The upper limit for pulsing, while still maintaining ok voltage levels, is about 40A.


    Continuous-Current Test Results
    image.png


    Pulsed-Current Test Results
    These tests are done to show the performance of the cell at higher pulsed current levels. If you are running your mod at these levels be aware that you risk overheating, and possibly venting, the battery if there is a malfunction or accidental pressing of your mechanical mod's button.
    image.png image.png


    Comments
    • At 10A continuous it reached about 2400mAh. This is fantastic performance for a 2500mAh-rated cell operating at 10A so I am rating this cell at 2500mAh.
    • Its temperature at 15A continuous was 70°C, a few degrees below the average for a cell operating at its CDR.
    • At 20A continuous the temperature rose to 83°C. This is at the upper limit of the average for a cell operating at its CDR.
    • At 25A continuous the temperature rose to 96°C. This is way too hot to set the CDR at this current level. Voltage sag is becoming more visible at the start until the battery warms up.
    • At 30A continuous the temperature rose to 103°C. This is above my 100°C safety limit and there is a lot of voltage sag.
    • At the 35A continuous the temperature rose to 112°C. This is a ridiculously high temperature and is dangerous. This is clearly not a 35A cell as is reported by some.
    • I am setting a CDR of 20A for this cell since at this current level its operating temperature is at upper limit for the average for a cell operating at its CDR. While operating any cell near its rated maximum current level causes damage to the cell, I would expect decent cycle life from this cell at 20A.
    • I have included pulsed discharges but I haven't set pass/fail standards for pulse testing yet. The discharges were done at 5sec on/30sec off, down to 2.5V. One chart shows the entire discharge at each level. The other chart is zoomed in to show the first 5 minutes to make it easier to see the voltage sag at different current levels.

    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

    18350 Safety Grades and Pulse Performance Data | E-Cigarette Forum

    18650 Battery Ratings -- Picking a Safe Battery to Vape With | E-Cigarette Forum

    26650 Safety Grades and Pulse Performance Data | E-Cigarette Forum
     
    MikeyConti, Tivaliman, CG138 and 8 others like this.
  2. WharfRat1976

    WharfRat1976 Vaping Master Verified Member ECF Veteran

    May 31, 2014
    Austin, Texas
    Great work as always, Mooch.

    Quick question:
    If a good 18650 cell has 500 cycles lifetime, how many cycles are "lost" due to recharging the cell at 2 amps.

    Assume recharges when the cell falls to 3.5volts.

    Thank you.
     
  3. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    I don't know. It depends on the cell. I haven't done enough cycle life testing with different cells to be able to say.
     
    WharfRat1976 likes this.
  4. Tivaliman

    Tivaliman Senior Member

    Apr 9, 2016
    This is excellent work, mooch! I get it now. Easy easy wut a sleazy. I just got one question. I'm a newb at this.
    I bought a pair of Lg he4 18650 35a 2500mah lmr. This is what it says on the order description. I understand from your table that it is actually 20a and at 35a it's just beyond safe. I have a sigelei 150w and purchased the batteries from there too, how would I know how much I'm pushing, since it only gives readings of wattage and volts? Are these batteries ok for my mod? Please help as I feel like I been ripped off.
    This doesn't discourage me from vaping, my life has improved so much because of it!
     
  5. KenD

    KenD Vaping Master ECF Veteran

    Aug 20, 2013
    Stockholm, Sweden
    This is the formula for calculating amp draw on a regulated device:

    Watts (+10% to account for chip inefficiency) / battery cutoff voltage = amps

    A two-battery parallel device:

    132 (120w + 10%) / 3.2v (a very common cutoff voltage) = 41.25 amps. As it's a parallel mod the amp draw is divided between the batteries, so 20.625 amps per battery

    A two-battery series mod:

    132 (120w + 10%) / 6.4v (the voltages of the batteries are added in series battery setups) = 20.625 amps. With series mods the amp draw is not spread out, so it's 20.625 amps for each battery.

    As you can see, for amp draw per battery it doesn't matter if the mod is series or parallel.


    Sent from my M7_PLUS using Tapatalk
     
  6. Tivaliman

    Tivaliman Senior Member

    Apr 9, 2016
    Wow... That is awesome, KenD. I was just on an ohms law calculator scratching my head. But this I understand. I don't learn anything until I'm under some risk.
    Thank you very much.
     
    beckdg and KenD like this.
  7. KenD

    KenD Vaping Master ECF Veteran

    Aug 20, 2013
    Stockholm, Sweden
    Check out steam-engine.org. There you can calculate amp draw more quickly, as well as check values for coil builds (and much, much more).

    Sent from my M7_PLUS using Tapatalk
     
    beckdg and Tivaliman like this.
  8. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    There's a bit of series/parallel reversing going on there. :)
     
    beckdg and Tivaliman like this.
  9. KenD

    KenD Vaping Master ECF Veteran

    Aug 20, 2013
    Stockholm, Sweden
    How embarrassing! I'll correct it. Good thing the amp draw is the same in both cases :)

    Sent from my M7_PLUS using Tapatalk
     
    beckdg and Mooch like this.
  10. beckdg

    beckdg ECF Guru Verified Member ECF Veteran

    Oct 1, 2013
    MD
    @Tivaliman

    Good move, brother.

    Happy to see you took the advice and went straight to it.

    Keep up the good work.

    You'll do just fine.

    Tapatyped
     
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