Efest Metallic Purple 20A 2500mAh 18650 Bench Test Results...accurately rated 20A, the HohmWork

Discussion in 'Batteries and Chargers' started by Mooch, May 31, 2016.

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  1. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    These cells were donated for the purposes of testing by Efest. Thank you! To prevent any confusion with the eGo-type "batteries", I use the term "cell" here to refer to a single 18350, 18650, 26650, etc.

    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 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 continuously.

    image.jpeg Packaging for all new 18650's

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


    Bottom Line
    Surprisingly, this new Efest is accurately rated at 20A and 2500mAh and rewraps the excellent Hohm Tech HohmWork cell. While the new metallic purple Efests still have the useless "pulse" rating in large lettering on the wrap, I applaud Efest for showing both the continuous and pulse ratings. This is a great first step towards having accurate ratings on all of our batteries. The new metallic wrap 18650's also ship with a plastic battery case, a welcome change.

    This Efest is identical in appearance to the HohmWork 20A 2500mAh cell and is essentially identical in performance. It is an enhanced version of the LG HE2 and this is reflected in the Efest's performance.

    When I mentioned to Hohm Tech that this Efest seems to use their HohmWork cell I received the following (understandable) response as part of our discusssion:
    "Hohm Tech, Corp. has officially opened the doors to licensing the tech to select brands and/or manufacturers simply as a move to get safer cells with robust capabilities into the hands of consumers (1st official licensing issued March 2016). Hohm Tech realizes there are brand loyal consumers, in which many of these consumers will now be using a new battery (not new brand) with or without their knowing. Hohm Tech will not disclose the brands and/or manufacturers which are or will be licensed to use Hohm Tech cells or other areas within the IC/HT tech. Although we will not be disclosing these details, we are unmeasurably honored the industry has welcomed our efforts and focus of delivering safer batteries with workhorse capabilities."

    Only time will tell us if this is the only cell that Efest will use for the 2500mAh or whether they will use multiple different cells like they did for their earlier 3000mAh cell.


    Continuous-Current Test Results
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    Pulsed-Current Test Results
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    Comments
    • At 10A continuous it reached about 2350mAh. This is good performance for a 2500mAh cell at 10A so I am rating this cell at 2500mAh.
    • At 15A continuous the temperature rose to 67°C. This is below the average temperature of a cell running at its continuous discharge rating (CDR).
    • At 20A continuous the temperature rose to 79°C. This is the average temperature of a cell running at its CDR and is an indication that this is the cell's true rating. There's no sign of extra sag in the discharge curve that would indicate that the cell was being operated at above its rating.
    • At 25A continuous the temperature rose to 92°C. This is way above the average temperature of a cell running at its CDR and is an indication that we're above the cell's true rating. There is also some extra sag appearing in the discharge curve and loss of capacity that would indicate that the cell was being operated above its true rating.
    • I am setting a CDR of 20A for this cell. Operating at that level would bring the temperature of this cell up to the average of 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 continuous.
    • 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
     
    gerrymi, MikeyConti, Baditude and 2 others like this.
  2. sonicbomb

    sonicbomb Vaping Master Verified Member ECF Veteran

    Feb 17, 2015
    1187 Hunterwasser
    This may sound like collective hubris, but have we influenced Efest to do the right thing? I still would not buy this or any of their other cells, as who knows what they will pull out from under their dirty plastic macs at a later date.
     
    MikeyConti, Mooch, KenD and 2 others like this.
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