The costs of running this huge site are paid for by ads. Please consider registering and becoming a Supporting Member for an ad-free experience. Thanks, ECF team.

Efest Purple 32A/64A 3500mAh 26650 Bench Test Results...only a 10A+ battery!

Discussion in 'Batteries and Chargers' started by Mooch, Oct 3, 2015.

Thread Status:
Not open for further replies.
Image has been removed.
URL has been removed.
Email address has been removed.
Media has been removed.
  1. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    This cell was purchased by me and used only for testing. To prevent any confusion with the eGo-type "batteries", I use the term "cell" here to refer to a single 18650, 26650, etc.

    These are safety-oriented tests, not for performance. Though you can get a lot of performance information from them they are primarily done to check the manufacturer's/rewrapper's ratings
    and to establish safe continuous discharge limits.


    Disclaimer
    The 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 batteries 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. My safety precautions are the ones I have elected to take and you should not assume they will protect you if you attempt to do any testing. Do the research and create your own testing methods and safety precautions.

    image.jpg image.jpg image.jpg image.jpg


    Bottom Line
    In my opinion, when compared to its ratings, this is a terrible performing battery. This is a 10A+ continuous discharge current (CDR) cell with very low capacity for its rating. I recommend not using it above 15A as it gets badly damaged at 20A. When attempting a 4 second pulse at its 64A rating, the voltage instantly plunged to my 2.5V cutoff.

    Constant-Current Test Results
    image.jpg

    Pulsed-Current Test Results
    These pulsed-current tests are only done to show the performance of the cell at its pulse or maximum discharge rating.
    image.jpg


    Comments
    • The constant-current graph has two temperature plots on it using the CBA's own temperature sensor. The sensor reads over 20°C too low and these tests were done for an upcoming blog entry. I thought the temperature plots could be deleted the same way the current plots can be...I was wrong. My apologies for the confusing graph.
    • The cell is clearly marked as being rated at 32A continuous and 64A pulsed.
    • At 10A the cell reached about 2575mAh. This is pretty bad performance for a 3500mAh-rated cell at 10A. I am giving this cell a capacity rating of 2900mAh.
    • At 15A the maximum temperature reached 66°C. This should be too low a temperature to set 15A as the CDR but, as shown later, damage is already starting at this current level in my opinion.
    • At 20A the maximum temperature reached 72°C. This should be too low for a cell operating at its CDR. The voltage drop is severe though, quickly going below 3.2V. This indicates that the cell is operating at beyond its rating.
    • At 25A the temperature only rose to 79°C. The voltage quickly dropped to about 2.85V though. This is clearly not a 32A cell.
    • A discharge at 32A was done. The voltage instantly plunged the down to the 2.80V cutoff.
    • Two more cycles at 20A clearly showed signs of damage to the cell. I did not continue with the two additional cycles at the CDR, five total, that I usually do. The damage was already pretty severe. This isn't even a 20A cell and in my opinion some damage would still occur at 15A.
    • I am setting a CDR of 10A+ for this cell. While operating any cell near its rated maximum current causes damage to the cell, I would hope for good cycle life from this cell at 10A+. Its performance was so bad though I can't say for sure.
    To see how other cells have tested and how hard you can safely push them, check out these links:
    https://www.e-cigarette-forum.com/forum/blog-entry/list-of-battery-tests.7436/
    https://www.e-cigarette-forum.com/forum/blog-entry/18650-safety-grades-picking-a-safe-battery-to-vape-with.7447/
     
    • Like Like x 5
  2. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    Just tested the internal resistance of this cell when cold...53mOhms using a 16A/15mS pulse. Trying to calculate the internal resistance from voltage drops in the graph gives me 40-45mOhms. Pretty close as far as this kind of stuff goes, especially since it goes down when the cell is warm/hot.

    But either value is high and helps to explain the large voltage drops that cripple the cell at high amps.
     
    • Like Like x 1
  3. Phassat

    Phassat Super Member ECF Veteran

    Nov 9, 2014
    Planet Earth
    Thanks to keep testing cells.... Always look at your test first before purchasing any 18650 or 26650... Been a huge help
     
    • Like Like x 2
  4. Danny_uk5

    Danny_uk5 Full Member

    Aug 22, 2015
    Sorry to hijack this thread but I didn't want to make a new one.

    Am I correct in thinking this is just a 10amp battery?

    I just contacted the vendor with this information (Toally wicked) and they had this to say about it:

    Your post will be reinstated if the claims are in any way substantiated, until then it has been removed to a non public part of the board. The world is full of "experts" and places like Reddit attract them, I think it is fair for us to put the claims to the manufacturer before allowing this to continue.


    EDIT: I found a different set of test results regards the battery in question. In all honesty, my head is spinning from all of this.

    Please note - I don't claim to understand the graphs. But I do understand amp limits and I always build within them limits.

    http://lygte-info.dk/review/batteries2012/Efest IMR26650 3500mAh (Purple) 2014 UK.html
     
  5. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    in my opinion that review shows that the battery could be rated at 20A, maybe more. I would need to know the temperatures to say for sure. But, it's from 2014 and I don't know if that battery uses the same cell as the one I tested. You have to be careful when comparing tests taken at very different times. :)

    You won't be able to send anyone's test results to a vendor. They sell the batteries and have to use the manufacturer's/rewrapper's ratings. They won't be able to spend the time to sort through who's tests are valid or not.
     
  6. Danny_uk5

    Danny_uk5 Full Member

    Aug 22, 2015
    It's kind of unbelievable that we live in a world where the Goverment is trying to cut down E-Cigs and battery makes can get away with making substandard parts, while advertising them to be XYZ.

    SO let me be a noob and enquire if the Efest 26650 is just a 10amp battery at best ? I know I sound stupid, but I need a definate yes or no on it. IF so, I'm returning it tomorrow and I've got some other ones on order - mnke.
     
  7. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    It's not a definite yes or no type situation. :)
    In my tests, using my personal standards for what constitutes a certain current rating, and for the cells I tested, I gave them a 10A+ rating. Of course, they can be pulsed far beyond that.

    In my tests the MNKE's did much better.
     
  8. Danny_uk5

    Danny_uk5 Full Member

    Aug 22, 2015
    Then forgive my next question, what's the pluse rating at then?
     
  9. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    I don't have a pulse rating standard set to judge any of these cells with yet. It's much, much more complex than I ever realized. Certainly explains why so many batteries just double the continuous rating and call it a day. You can do that if you want and you'll probably be OK. The battery certainly won't overheat.

    Just be aware that any coil or wattage setting that draws that much current could potentially be a problem if the mod autofires or a mechanical mod's button breaks or gets accidentally pressed in a pocket (causing the current to be continuous). That's a concern for some and not a concern at all for others.
     
    • Like Like x 1
  10. Topwater Elvis

    Topwater Elvis Vaping Master ECF Veteran

    Dec 26, 2012
    Texas
    • Like Like x 2
Thread Status:
Not open for further replies.

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice