Bench Test Results: Efest Purple 35A 3700mAh 21700...only 30A but a great performer, similar to S35

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Electron Wrangler
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  • 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 continuous 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.

    4BDC7A67-FB9C-46C9-BBB6-A5447D309BEC.jpeg 44B944FC-3F1E-4148-B6BE-C02C5B048652.jpeg 181757AD-9E80-4E78-B731-F702397ACB07.jpeg 5F1BDC80-5949-4B3F-BF13-E886B1B40B06.jpeg

    Bottom Line
    This is a great performing cell but it runs at close to 90°C at its 35A continuous rating. This is too hot in my opinion for decent cycle life as most cells say not to exceed 75°C-80°C. I don’t know why Efest decided to exaggerate the rating but it was completely unnecessary.

    Actually, I do know why...our obsession with high rating numbers. I just don’t like that these companies feed into that instead of just showing us it’s a great performing 30A battery.

    This Efest’s appearance and performance is very similar to the Golisi S35 but different enough that I cannot say they are the same cell. The Golisi is a bit better performer at lower current levels but the Efest shows less voltage sag at the start at 30A.

    I am estimating the ratings for this Efest to be 30A and 3700mAh. The 30A rating helps to keep its temperature down closer to the 80°C limit used by other cells.

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

    Continuous Current Discharge Graphs
    0ACCC642-DDEA-4EE1-A5D2-4F750223E4D3.jpeg 466338F9-4C01-4E33-B0B2-18939D6A675F.jpeg

    Ratings Graphic

    Performance Specs
    • DC Internal Resistance = 15.0mOhms (milliohms) average for the two cells.
    • Total energy delivered down to 3.2V at 10A continuous = 10.6Wh (Watt-hours) average
    • Total energy delivered down to 3.2V at 20A continuous = 8.7Wh (Watt-hours) average
    • Total energy delivered down to 3.2V at 30A continuous = 6.0Wh (Watt-hours) average
    To see how other cells have tested check out this link:

    Derek Cross

    Senior Member
    ECF Veteran
    May 16, 2015
    So I bought 2 and I've been using them for a week or so now, and they really are nice cells at higher current mech setups. Very good cells so far.

    I recently acquired some 30t's (Samsung) and these Efest perform similarly. They last long too. My only thoughts are how they will hold up over time. My vtc5a and other better mech cells give me a few months of solid performance before showing enough sag where it's noticeable.

    Time will tell on this one, but for now these are second only to the 30t's in mech performance!

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