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Bench Test Results: Samsung 40T 35A 4000mAh 21700 Can Code N40T...appear to be genuine 40T’s

Discussion in 'Batteries and Chargers' started by Mooch, Jan 30, 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, LG, Panasonic, 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 protected battery pack. Never exceed the battery’s current rating and keep the plastic wrap and top insulating ring in perfect condition.

    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.


    Bottom Line
    There are Samsung 40T’s being sold that have a different code on the metal can than what is expected and I’ve been asked a lot if these are genuine. You can read this code through the wrap. It’s the first line of codes, near the top. Usually that code has a zero as the second character to indicate that the cell is a 20, 30, or 40 series Samsung. But these cells have “N40T” as the top code line.

    I do not know why a different style of code is used but based on the two cells I tested it appears that these are genuine Samsung 40T’s. They tested identically to the production 40T’s I recently tested (with a 2IA3 date code on the wrap) but I do not know if these are production cells. These cells have a date code of 2IA2 which could be just one day earlier than the 2IA3 cells.

    The 40T is a fantastic cell, especially for regulated mods at under 25A/75W or so. At above 25A/75W or so the Samsung 30T is the better performer. The 40T is best at moderate power levels where it can be the most efficient. These 40T’s are still amazing 30A batteries though!

    If you are running your mod at around 75W per battery you will have to try both the 30T and 40T to see which performs better for the way you vape. It’s just not possible to predict.

    The two cells I tested delivered 4100mAh and 4131mAh at 0.8A (0.2C) down to 2.5V. This is good consistency.

    I am estimating the ratings of these date code 2IA2 cells with the N40T can code to be the same as the earlier preproduction versions of the 40T because I do not know if these are production cells or not. I am rating these at 25A continuous with a “temperature-limited” rating of 35A if you keep them under 80°C.

    Two cells were donated for the purposes of testing by Fogstar (Fogstar - The UK's #1 trusted source of 18650 Batteries). Thank you!

    Continuous Current Discharge Graphs

    Ratings Graphic

    Performance Specs
    - DC Internal Resistance = 13.5mOhms (milliohms) average for the two cells.
    - Total energy delivered down to 3.2V at 10A continuous = 11.4Wh (Watt-hours) average
    - Total energy delivered down to 3.2V at 20A continuous = 10.0Wh (Watt-hours) average
    - Total energy delivered down to 3.2V at 30A continuous = 8.3Wh (Watt-hours) average

    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 and testing 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
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  2. Torsten_MTL

    Torsten_MTL New Member

    Feb 28, 2019
    Many thanks for all your tests!
    Could you or anyone else explain what the batchcode means? You have tested 40T with batch codes: 2IA2, 2IA3 and 2I24
    I have got a 40T with batch code 2BH3
    Any ideas what that could mean? Could this be a newer one? Or ist it most likely an older one? Is there anything we can read out of this batch code?
  3. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    The batterybro date code tool doesn’t work for some codes (18650 Date Code Lookup Tool) and I don’t know if it’s correct for the codes it does work for with these newer cells. I don’t have the code lookup sheet for the 40T but I assume that 2BH3 is an older code than 2IA2 since , alphabetically/numerically, 2BH3 is “before” 2IA2.

    This is just a guess though.
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