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Samsung 25R - high drain 18650 Li-ion cell's capacity test
#1
Video 
Samsung INR18650-25R is a 2500mAh Li-ion cell of 18650 size which supports continuous discharge at up to 20A.
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The battery was bought from my reliable supplier (Queen Battery) and tested with ZKETECH EBC-A20 and a self-made battery holder. It's a PC-connected battery tester supporting 4-wire measuring and discharging at up to 20A.
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I've used version 3.0 of my battery holder based on 0.5mm thick pure copper terminals
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I've followed all the prescriptions of the IEC61960-2003 standard 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 23.0-24.5°C. To be sure in results i've done each test minimum twice (usually 3-4 times).


Samsung INR18650-25R

The cell is marked as INR18650-25R SAMSUNG SDI 5 2H62 which means that the production date is 02 Jun 2017.
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The main specs from Samsung 20S datasheet:
Nominal capacity: 2500mAh
Nominal voltage: 3.6V
Standard charge current: 1.25A (0.5C)
Maximum charge current: 4A
Charge cut-off current: 100mA
Charge end voltage: 4.20V
Max. continuous discharge current: 20A (8C)
Discharge cut-off voltage: 2.5V
AC impedance at 1KHz: ≤18mΩ
Max weight: 45g

Measured initial DC IR at 2.5A in fully charged condition was 14.8±1.2mΩ

Measured weight of the tested cell was 43.59g
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Capacity test results:
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At 0.2C / 0.5A 25R's capacity was noticeably higher than the 2500mAh declared which is good, but this cell is meant to be discharged at much higher currents. All the way from 5 to 20A the capacity was playing around 2450mAh and never went below 2400mAh! The energy at 20A was 7.83Wh and the curve looks excellent! The verdict - 25R is a good choice if you're looking for a 20A cell.

Here is the video version of this review:
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Check out my YouTube channel for batteries, chargers and other stuff reviews.
I've launched my blog where you can find all my reviews in one place. Every new test/review will be first published on YouTube and in the blog. I'll be happy to see new subscribers, comments, suggestions and just your thoughts.
Korishan and niktak11 like this post
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