Samsung 26J (26JM) 2600mAh low price cell's capacity test

Samsung ICR18650-26J is a 2600mAh Li-ion cell of 18650 size which supports continuous discharge at up to 5.2A.


The battery was bought from my reliable supplier (Queen Battery) and tested withZKETECH EBC-A20and a self-made battery holder. It's a PC-connected battery tester supporting 4-wire measuring and discharging at up to 20A.


I've used version 3.0 of my battery holder based on 0.5mm thick pure copper terminals



I've followed all the prescriptions of theIEC61960-2003standard concerning battery's capacity measurement. Before each discharging cycle each battery was charged at standard charge current mentioned in its datasheet to charge end voltage. Before each discharging or charging i've held a 1-1.5hrs pause. The environment temperature was 23.0-24.5C. To be sure in results i've done each testminimum twice(usually 3-4 times).


Samsung ICR18650-26J

The cell is marked as ICR18650-26J M SAMSUNG SDIEM THR2 which means that the production date is 02 Apr 2017.


The main specs from Samsung 26Jdatasheet:
Nominal capacity:2600mAh
Minimum capacity:2550mAh
Nominal voltage:3.63V
Standard charge current:1.3A (0.5C)
Maximum charge current:2.6A (1C)
Charge cut-off current:0.13A (0.05C)
Charge end voltage:4.20V
Max. continuous discharge current:5.2A (2C)
Discharge cut-off voltage:2.75V
AC impedance at 1KHz:?100m?
Max weight:45g

Cycle life:
After 300 cycles using 1.3A charge / 1.3A discharge the capacity measured at 0.2C discharge should be ?1785mAh (70% of initial minimum capacity).

DC IR at 2.6A in fully charged condition was 42.32.7m? (measured using EB Tester Software's Resistance test feature).

Measured dimensions: 18.3mm (diameter) 65.0mm (length).

Measured weight: 43.87g.


Capacity test results:

At 0.2C/0.52A the capacity was a very little bit higher than 2600mAh declared. At 2A and 5A discharge it was around 2450mAh. The curves look excellent.
Samsung limits the charge cut-off current by 0.05C instead of more common 0,02C and the discharge cut-off voltage by 2.75V instead of 2.5V. With 0.02C and 2.5V the results would be better but i think Samsung is worried about cycle life of this cell - 70% of initial capacity after 300 cycles 0.5C charge / 0.5C discharge doesn't make me cry wow. Whatever, real-world cycle life could differ.
Samsung 26J is a good low-drain medium capacity 18650 cell without any special features. The price (somewhere around/below $2) makes it an excellent choice for large battery packs.

Here is the video version of this review:


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Wow ... that's rather a short life .... " 300 cycles capacity 70% original " Works out at around 5Whrs/$ great value for a 18650..

Cycle life , normally around 400 (charged to 4.2 V) ... this means 400 cycles before below 80% original capacity , for some reason this manufacturer has given figure for 70% .

This cell probably reaches 80% at around 200 cycles ....

For some uses this may not be an issue , I have cells in torches which only get a recharge every month . These cells maybe acceptable for ebikes only ridden once a week , for powerwalls , doubtful.

Putting the production date code on this cell (HR2) ... into this calculator https://batterybro.com/pages/18650-date-code-lookup-tool .. shows it was manufactured April 2017 ... rather old , they do have a shelf life ... "Typically the big manufacturers (Samsung, LG, etc.) will guarantee their cells for up to 6 months after production...."

That's why i emphasized that. 300 cycles at only 0.5C chg/dischg putting the capacity down to 70% is something worth mentioning. I think if a pack would be large enough to do max 0.2C chg/dischg cycle life would be good, but it means that this cell is limited to be used in such packs or in devices which are rarely used. In other cases there are better cells to choose from.

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P.S.
The "M" in 26JM means that the cell is made in Malaysia. The 26J is also made in Tianjin, China. Chinese cells are marked as 26JT (though i never saw one).

I don't know if an old production date is typical for most new cells... Where have these cells been for over two years?? I would think manufacturers want a quick turn around and would normally sell within a month of production. But it doesn't seem to have reduced capacity!

Minimum 1 year it was on my shelf)))

Do you think manufacturers quote cycle life as a worst case scenario? Like how they quote (1) rated, (2) typical, and (3) minimum capacities of their cells?

I mean, 70% after 300 cycles is embarassing for Samsung, no matter the price. They must be getting stingy on the cobalt content.

I'm going to be releasing the next set of my cycle testing in the next day or so and my 300 cycle/80% rated LG cell is over 400 cycles with less than 10% degradation over the course of my testing, so I'm thinking the ratings manufacturers give are the worst case scenario with respect to cycle life.

Dallski said:

I'm going to be releasing the next set of my cycle testing in the next day or so and my 300 cycle/80% rated LG cell is over 400 cycles with less than 10% degradation over the course of my testing, so I'm thinking the ratings manufacturers give are the worst case scenario with respect to cycle life.

Click to expand...

Looking forward to it!

Most of my F,B and C series of this cell were fine over time. H series were excellent (the few I had).
Others not so good (like some Ds).
If they got to 'J' that means it's the 10th tech release of this cell, so there could be improvements due to better process over time or it could be worse due to manufacturing process wear-out. Only time will tell. Hope it's an improvement over H-series.