Bench Test Results: AWT 40A 4200mAh 20700…preposterously overrated, false data, DO NOT BUY

Discussion in 'Batteries and Chargers' started by Mooch, Jun 28, 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. You are responsible for your own safety.

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

    If the cell has only one current rating number on it, or if it 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.

    IMG_5688.JPG IMG_5689.JPG IMG_5690.JPG IMG_5691.JPG IMG_5692.JPG IMG_5694.JPG


    Bottom Line
    This cell has only one rating on the wrap, “40A”. Simply put, that is ridiculous.

    That, and other things, has forced me to issue my first ever DO NOT BUY recommendation. The biggest problem is that this appears to be a rewrap of the Sanyo 15A-16A 4000mAh NCR20700B cell that AWT decided to grossly exaggerate the current rating for. The capacity rating is exaggerated too. This cell is identical in appearance and essentially identical in performance to the Sanyo NCR20700B.

    Aweite (AWT) doesn’t appear to have a web site but this cell is on their Alibaba pages. Earlier I found a page that referred to the Sanyo NCR20700B in the description for this cell and issued a warning (https://www.facebook . com/batterymooch/posts/1899722450317332).

    The various Alibaba pages for this cell (https://imgur . com/a/voBPg) have ratings from 25A to 40A using the terms “max cont. discharge rate”, “fast discharging current”, “max discharging current”, or no description of what the “40A” number means at all. I guess you get to pick the rating that fits your mood! But at only 25A continuous this cell got hot enough to boil water, 101°C.

    One Alibaba page claims the following…

    - A tested capacity of 4150mA at 35A. That’s false. The cell only reached about 2500mAh, its temperature rose to 116°C, and it failed. Probably due to one of Sanyo’s internal protection devices being activated due to the dangerously high temperature.

    - A battery temperature of 37°C for a 10A discharge. That’s false. The temperature rises to about 60°C at 10A (down to its rated 2.5V cutoff).

    - A rating of 15C. That’s false and is lousy math too. Their claimed 4200mAh capacity and 25A/40A ratings would mean it’s a 6C/9.5C cell…if those current and capacity ratings were accurate. They’re not though. This is a 4C cell.

    Another Alibaba page gave it a rating of 0.2C to 2C, which is just beyond silly and obviously an error they didn’t feel the need to correct.

    I am giving this AWT a rating of 16A and 4000mAh. Its maximum vaping amps (MVA) rating is 25A, limited by extreme voltage sag.

    I am also giving this AWT cell a DO NOT BUY recommendation due to the outrageous overrating and false performance data on Alibaba. If you need an ultra-high capacity 20700 cell for low to moderate power vaping at up to 10A/37W per cell then get the Sanyo NCR20700B.

    The two cells that were tested were purchased by me from ebay’s r-lsales.


    Continuous-Current Test Results
    IMG_5686.jpg


    Pulse-Current Test Results
    Pulse testing was not done because this is just a Sanyo NCR20700B rewrap.


    Comparison to the Sanyo NCR20700B
    IMG_5687.jpg


    Comments
    • Discharges at 10A and 20A were done to compare the AWT's performance to the Sanyo NCR20700B.
    • A discharge at 25A was done to show this cell's temperature and performance at its one of its claimed ratings.
    • A discharge at 35A was done to show the true capacity delivered vs. what AWT's Alibaba page says.
    • A discharge at 40A was done to show this cell's temperature and performance at one of its claimed ratings.
    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
     
    KenD, Izan, ImThatGuy and 1 other person like this.
  2. sonicbomb

    sonicbomb Vaping Master Verified Member ECF Veteran

    Feb 17, 2015
    1187 Hunterwasser
    Ding dong goes the shame bell.
     
    ImThatGuy likes this.
  3. Hatrix

    Hatrix New Member

    Jun 28, 2017
    Thank You Mooch!

    I saw these things on Ebay yesterday afternoon and the numbers given didn't look realistic, so I passed. Wanted to wait until you tested them.

    You rock!
     

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