This is an extremely popular cell in Asia, especially the Philippines. It is an average performing 18650 cell that has a slightly exaggerated current rating. The Samsung 25R performs a bit better and the Sony/Murata VTC5A performs much better than this Kdest. Its very high internal resistance means it suffers from a lot of voltage sag, very badly affecting its performance.
The capacities for the four Kdest Orange cells I tested ranged from 2613mAh to 2676mAh at 480mA (0.2C) down to 2.5V. This isn’t great consistency but it is significantly above its 2400mAh rating and this inconsistency is typical of cells not from the major manufacturers. I am rating it the same as Kdest did, 2400mAh, to prevent confusion.
I also tested two of these cells that I purchased from a Philippines shop owner (visiting New York City) that were slightly different in appearance and that had a lower capacity but they were still a bit over the 2400mAh claimed rating. Kdest says that was an older batch and all the cells shipping now are the ones I tested at 2600mAh or higher. You won’t notice any difference between these cells unless you are going down below about 3.0V though so you are not using “bad” cells if you have the older 2400mAh ones. It’s not worth replacing your 2400mAh ones with the newer 2600mAh ones either. You won’t notice any performance change.
I hope that any future changes in Kdest cells also have a change in the wraps to let us know which cells are which. If a cell I have tested is ever changed without a wrap update then that cell will receive a Do Not Buy recommendation.
This Kdest cell reaches about 94°C when run at its claimed rating of 25A. This is much too hot to be rated that high. After only ten cycles at 25A there was a noticeable drop in performance. The amount of voltage sag at 25A is huge too. I am rating this cell at 20A continuous.
The 50A “max” rating is useless. When discharged at that level the voltage instantly dropped to about 2.9V. In addition, Kdest does not specify what was used to set the “max” rating so we can’t use it to compare this cell to any others. This cannot be called a 50A battery just because it doesn’t instantly explode at 50A.
I am VERY happy though that after discussing my test results with Kdest that they are going to be updating the wraps! They said they will be lowering the continuous current rating (CDR) to 20A and removing the 50A “max” rating from the wrap. This is great news. I don’t know when this will happen but will I post as soon as I get that information.
Kdest sent me the datasheet and MSDS (this cell is listed as being NMC chemistry) but I will not receive the UN38.3 safety test report for three weeks or so. If I do not receive it within one month, by January 10, 2020, then this cell will be given a Do Not Buy recommendation.
Why am I not slamming Kdest now with a Do Not Buy recommendation for the missing safety document? I’m not trying to hurt companies that don’t have the safety documents. I am trying to get them to change how they set ratings and to have them get the documents for every cell before anyone tests them. This might mean giving a company a little bit of slack if they have some documents but not others. If they don’t follow through on their promises though then I will definitely give the cell(s) a Do Not Buy recommendation!
Having no documents, ignoring my requests for documents, or having documents with obviously faked information leads to an instant Do Not Buy recommendation though.
Kdest (www.kdest.com) donated four cells for testing, thank you!
Ratings graphic: https://imgur.com/a/Dr3AtSL
Full Test report: https://bit.ly/2LI5bDu
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These tests 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” batteries 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.
Any rating in my ratings tables can change at any time as different grade cells appear on the market, we get swamped with fakes, or new information becomes available to me. Please, never assume that the ratings in the tables are permanent and will never change! Always download the latest version before considering any cell purchase.
To see how other cells have tested check out this link: https://www.e-cigarette-forum.com/forum/blog-entry/list-of-battery-tests.7436/
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