18500 shares the same 18mm diameter with 18650 but it's 15mm shorter (18x50mm).
This size is often used in digital cameras' battery packs, usually in 2S configuration.
Panasonic NCR18500A is 2000mAh rated cell which supports continuous discharge at up to 4A.
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.
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 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 3-5 times).
This flat-top cell's heat shrink tube contains the model number, "Made in China" mention and B 77271W marking. The tube doesn't go over the negative pole and ends in 1.5mm to it. It's common for 18500 cells.
The main specifications of Panasonic NCR18500A from its datasheets (first and second):
Rated capacity: 1900mAh at 20°C
Minimum capacity: 1940mAh at 25°C
Typical capacity: 2040mAh at 25°C
Nominal voltage: 3.6V
Standard charge current: 1358mA (0.7C)
Charge end voltage: 4.20V
Charge cut-off current: 39mA (0.02C) (100mA used)
Max continuous discharge current: 3880mA (2C)
Discharge cut-off voltage: 2.5V
Max weight: 33.5g
After 500 cycles using 1358mA (0.7C) charge with 39mA (0.02C) cut and 1940mA (1C) discharge with 2.5V cut the capacity should be around 1700mAh (~85% of initial capacity).
DC IR at 1940mA in fully charged condition was 38±1mΩ (measured using EB Tester Software's Resistance test feature).
Measured dimensions: 18.2mm (diameter) × 49.2mm (length).
Measured weight: 32.52g.
Capacity test results:
At 0.39A (0.2C) NCR18500A almost reached 2100mAh level. At 2A discharge 1981mAh/6.9Wh looks very good, especially when we are looking at that almost linear beautiful discharge curve. At 4A the situation doesn't change a lot, only the numbers go slightly down - 1940mAh and 6.5Wh.
Excellent results are completed with 2.5V cut-off which means that this cell is compatible with almost any BMS and with very good cycle life. Declared 500 cycles at 0.7C/1C down to 85% is a thing to pay attention at.
Here is the video version of this review:
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