Protected MJ1 Lithium-ion Cell Review

The Protected MJ1 lithium-ion cell is a button top 18650 that offers a high capacity of 3500mAh. Read on for testing!

Official Specs

Here’s a link to the Protected MJ1 Lithium-ion Cell product page.

  • Max Continuous Discharging Current: 10A
  • Typical Capacity: 3500 mAh (3350mAh minimum)
  • Style:  BUTTON top
  • Approximate Dimensions (including button): 69.1mm length x 18.6 mm diameter
  • Discharge cut-off voltage: 2.5V (approximate)
  • Voltage: 3.6V
  • Full Charge Voltage: 4.2V
  • Charge Current:  1.675A standard
  • Protection Cutoff Current:  ~20A
  • Protection IC:  Ricoh R5478N101CD
  • MOSFETS:  FNK10N25B (Quantity 3)
  • Origin:  Cell made in Korea, button top manufactured in China, Protection IC made in Japan

Short Review

These cells are good in their rated range.  They were of particular use for me since they’re just a little bit longer and they’re also button top.  They are the only cell I had that would work in one of my review lights!

Long Review


These cells ship individually wrapped, inside a cardboard box.  The cardboard box will hold 2 cells.

There’s a touch of foam under the cells, but they won’t move around much anyway.


Build Quality

Bare, these cells are LG MJ1 cells.  LiionWholesale “then adds the high quality PCB along with the button top in an ISO certified factory to all safety standards. A black wrap is put over the top to hold it together.”  LiionWholesale also adds a very descriptive sticker.  Not just that “regulation” sticker, either.




The positive end is a button top, and the negative end is flat, with the wrapper wrapping over about 2mm from the edge.



Officially:  Approximate Dimensions (including button): 69.1mm length x 18.6 mm diameter.

They’re not short 18650’s.  But they are perfect for some lights, which need longer cells!  (The Imalent RT35 is one such example.)


The testing I’ve done should be familiar.  I decided not to reinvent the wheel, and include similar data to what the cell testing legend HKJ does.  Please view this as appreciation for the work HKJ does, and not a simple copying of his work.  Thank you HKJ!

I’ve also included another chart or two, which were made thanks to the help of u/parametrek.  Thanks parametrek!!

Discharge tests.



Just for giggles, I did test a 20A current drain (even though this is a 10A rated cell, with OverCurrent Protection rated at 20A), and the cell protection did trip.





Charge test


Power, Constant 10W


Internal Resistance


Graph of internal resistance (IR).  This is shown over the course of a discharge, and comparisons are made between the nearest discharge currents (ie 0.2A vs 0.5A) and also vs disparate discharge currents (0.2A vs 7.0A).

Spec Sheets

Here’s the spec sheet for this cell.


It’s still a bit early in my cell testing career to make any long-term thoughts, but I can say that these cells perform well at their specifications (10A max drain).

Buy these cells at LiIonWholesale!


  • These cells were provided by LiIonWholesale for review. I was not paid to write this review.
  • This content originally appeared at  Please visit there for the best experience!
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