Bench Test Results: Tenpower 40TG - 35A 4000mAh 21700

Mooch

Electron Wrangler
ECF Veteran
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  • May 13, 2015
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    These tests below only note my personal opinion for the 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, EVE, Lishen, BAK, or Sanyo can change at any time! This can be 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. Never use them 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.

    IMG_7940.jpegIMG_7941.jpegIMG_4014.jpegIMG_4015.jpeg


    Test Results
    This cell is a good performer, about the same as the Molicel P42A and Samsung 40T3. It can probably be found at a lower price and is definitely worth considering.

    This cell is rated at 35A in the spec sheet but hits its 80°C max temp rating at about 30A (down to 2.5V) in my testing so I’m giving it an estimated 30A continuous rating and 35A temperature-limited rating. You can run it at 35A but stop before it reaches 80°C.

    Some other results and info…
    • DC IR measured 11.8mOhms and 11.9mOhms for two cells. This is amazing consistency.
    • Capacities were 4088mAh and 4109mAh. This is decent consistency and is above the cell’s 4000mAh nominal rating.
    • The standard charge rating is 2A and “maximum” charge rating is 6A. I recommend staying at 2A or lower for long cell life

    Continuous Current Discharge Graphs
    Tenpower 40TG - 35A 4000mAh 21700 CC Tests - Oct 2024.jpeg


    Ratings and Performance Specs Graphic
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    18650 Ratings & Performance Table:


    20700/21700 Ratings & Performance Table:

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    To see how other cells have tested check out this link: Links To All 21700, 26650, 18350, 18500 Battery Tests
     

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