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Bench Retest Results: Murata VTC6A 4000mAh 21700...good performer, but not as good as previous test

Discussion in 'Batteries and Chargers' started by Mooch, Nov 9, 2019.

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  1. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    These tests below only note the ESTIMATED ratings for these batteries at the time I tested them. Any battery that is not a genuine Samsung, Sony, Murata, LG, Panasonic, Molicel, or Sanyo can change at any time! This is one of the hazards of using “rewrapped” or batteries from other manufacturers so carefully research any battery you are considering using before purchasing.

    Misusing or mishandling lithium-ion batteries can pose a SERIOUS RISK of personal injury or property damage. They are not meant to be used outside of a physically and electrically protected battery pack. Never exceed the battery’s current rating and keep the plastic wrap and top insulating ring in perfect condition. Use of any of these batteries is AT YOUR OWN RISK.

    Testing batteries at their limits is dangerous and should never, ever, be attempted by anyone who has not thoroughly studied the dangers involved, understands the risks, has the proper equipment, and takes all appropriate safety precautions.

    If the battery has only one current rating number, or if it only says "max", then I have to assume the battery is rated at that current level for any type of discharge, including continuous.

    91718EC1-6240-4501-BA77-AA112801C059.jpeg 12C5EE25-6BF7-4B4E-A3F7-E10AC6611032.jpeg 86124A5E-7BCB-4CB6-8FEA-A03A76002D7E.jpeg 73F40662-73C2-4E1D-BB31-7C7526E249C0.jpeg 74F20953-BBBB-4B26-A755-BB6A720B3530.jpeg


    Bottom Line
    This is a retest to make sure that we’re not having crappy cells dumped on us. These cells are good performers but they perform worse than they did when I last tested them in January, 2019. It could be that these are a lower grade. I don’t know if that is true or not though.

    The Murata VTC4’s, VTC5’s, and VTC5A’s I have tested all essentially equaled their Sony counterparts in performance. I would have expect the Murata 21700 VTC6A to continue to do the same so more testing is needed.

    The capacities for the two cells I tested were 4006mAh and 4024mAh at 800mA (0.2C) down to 2.5V. This is great consistency and typical of the cells from the major manufacturers.

    Murata does not give this cell a true continuous current rating in the datasheet, only a “temperature-limited” rating of 40A if you do not heat the cell over 80°C (frakkin’ hot).

    While this Murata is a good performing cell the Molicel P42A or Samsung 40T are a better choice for about 25A/75W and lower. The Samsung 30T is the better choice at above about 25A/75W.

    These cells have a tiny QR code square laser etched in the bottom of the metal can, near the outer edge. This cell also has a bottom vent ring. This could be a concern if you have a mod that presses very hard against the bottom of the cell. This could split open the vent or prevent its proper operation in case the cell was accidentally short-circuited or was run much too hard.

    I am giving the Murata 21700 VTC6A a continuous current rating of 30A and a “temperature limited” rating of 40A. At 30A continuous the cell temperature reaches about 80°C, its maximum rating. According to the datasheet you can run it at 40A if you do not allow it to reach 80°C. I am giving it a capacity rating of 4000mAh.

    Two cells were purchased for the purposes of testing by me.


    Continuous Current Discharge Graphs
    D5AA93E6-DF6D-47BC-8F08-A1FF42C236B9.jpeg


    Ratings Graphic
    6F7E1774-82C2-4E90-A0E9-2D459FC320D9.jpeg


    Performance Specs
    - DC Internal Resistance = 13.8mOhms*** (milliohms) average for the two cells.
    - Wh testing was not done.

    I want to work for the vaping community full time! If you feel what I do is worth a couple dollars a month and you would like early access to battery availability, battery and charger testing and news, and a say in what I test, then please consider becoming a patron and supporting my testing efforts: Battery Mooch is creating battery tests and educating vapers | Patreon.

    To see how other cells have tested check out this link: List of Battery Tests | E-Cigarette Forum

    ***I have switched test jigs, resulting in slightly lower IR readings versus my previous setup. Add 1.6mOhms to this IR value in order to compare these cells to others tested previously.
     
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