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Bench Test Results: Molicel P28A (2021-dated) - 35A 2800mAh 18650

Discussion in 'Batteries and Chargers' started by Mooch, May 3, 2022.

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  1. Mooch

    Mooch Electron Wrangler ECF Veteran Verified Member

    May 13, 2015
    These tests below only note my personal ESTIMATED ratings for the batteries I tested 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 property damage, personal injury, or even death. They should never be used outside of a fully protected battery pack and you use them at your own risk. Never exceed the battery’s true continuous discharge rating (CDR), never let it get colder than 0°C or hotter than 60°C, and keep the plastic wrap and top insulating ring in perfect condition. Never use a battery that is physically damaged in any way.

    Testing batteries at their limits is dangerous and should never 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.

    702BD172-7BC0-4DB5-8BFB-EBF6C3C5C078.jpeg 899DD92B-9078-4E7B-80E7-F61766435EB0.jpeg 069562AE-A4B9-4439-BE5D-3FCC294E1AA7.jpeg 97027479-2875-4783-AA8C-DED9EA027E63.jpeg


    Test Results
    It has been three years since I tested the Molicel P28A. With the 2021-dated cells being available I wanted to see if any changes in their performance has occurred over that time.

    All genuine 2021-dated P28A’s should have an “L” as the second character in the date code on the wrap. If it has a “K” that is a cell manufacturered in 2020, “J” = 2019, “I” = 2018, etc.

    I’m happy to report that the 2021-dated Molicel P28A’s ran noticeably better than the 2018 cells I tested three years ago. In my testing they outperformed the P26A at all current levels by several percent (check their E-Scores, link below). The 2021-dated P28A is one of the best all-around 18650’s you can buy and is a great choice for almost any use from 5A-25A.

    The datasheet for this cell lists a 35A “maximum discharging current” rating but notes that “cycle life is reduced at high rates”. This means Molicel says you can use the cell at up to 35A but the cell will age faster.

    The only maximum temperature limit I can find in the datasheet is 60°C so never allow the cell to get hotter than this. Cells start aging a lot faster when run at temperatures that high, above around 45°C, so it’s best to stay below 45°C whenever possible.

    Be aware that going over 60°C is very easy in a battery pack where each cell can heat up the ones around it and the pack is covered by insulating materials that slow down cooling.

    This 35A rating not a true continuous current rating you can use to compare against other cells. The P28A will get almost hot enough to boil water if run continuously at 35A down to its 2.5V cutoff. In my opinion Molicel rated this cell for its intended use in power tools and other applications where the cells are used only for short periods of time at high current levels.

    So while you can run this cell for short periods at 35A I recommend staying at 25A or lower to help improve performance (reduce voltage sag), extend cell life, and reduce the risk of going over the 60°C limit.

    The two cells I tested delivered 2814mAh and 2829mAh, exceeding Molicel’s 2800mAh typical capacity rating. This is great consistency.

    Two cells were purchased for testing by me from 18650BatteryStore (18650 Battery Store - Lithium Ion Batteries, Chargers and Accessories).


    18650 Ratings and E-Scores Table:
    18650 Battery Ratings Table | E-Cigarette Forum


    20700/21700 Ratings and E-Scores Table:
    20700/21700 Battery Ratings | E-Cigarette Forum


    Continuous Current Discharge Graphs
    2FCE9434-C4F0-4929-9023-CD7897B6E1A0.jpeg 1D13FD4B-FDAD-43E4-BA06-5C0A62893E96.jpeg


    Ratings and Performance Specs Graphic
    2682ED06-E52F-4685-B3E8-29403234D4D1.jpeg

    I want to work for the 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 and device tests | Patreon.

    To see how other cells have tested check out this link: List of Battery Tests | E-Cigarette Forum
     
    • Informative Informative x 9
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  2. Rossum

    Rossum "Chump" ECF Veteran Verified Member

    Supporting member
    Dec 14, 2013
    SE PA
    :vapor:

    FWIW, I got a batch of these not that long ago and tested eight of them for capacity down to 2.8V at 0.2C. The results:

    2747
    2744
    2750
    2754
    2750
    2755
    2754
    2756

    I think I would have gotten very similar numbers to your 2814mAh and 2829mAh if I had gone all the way down to 2.5V, but I don't like going that low with cells I intend to use in the real world.

    Only 12 mAh difference between the highest and lowest is very good consistency; considerably better than the 29 mAh difference I saw between highest and lowest on a batch of 10 P26A made in 2018 and tested in 2019. However, a batch of 8 VTC5A also made in 2018 and tested in 2019 still beat that, with only 8 mAh difference between highest and lowest.

    [​IMG]
     
    • Informative Informative x 3
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