14500 is the same well-known AA size we used to see. It means that the diameter of the cell is 14mm and it's 50mm long. 14500 is used to refer to 3.7V Li-ion or 3.2V LiFePO4 cells while AA is for 1.5V alkaline/other primary batteries and 1.2V Ni-Cd or Ni-MH rechargeable cells. Let's look at the difference in size between AA/14500 and other popular formats:
From the top to the bottom and the left to the right there are AAA/10440, AA/14500, 18650, 26650 and the new 26800 size.
Queen Battery QB14500 is a flat-top unprotected 700mAh-rated cell which also can be ordered with add-on protection PCB and button-top cap.
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).
Queen Battery QB14500 700mAh
The cell's heat shrink tube shows brief specifications but has absolutely no data about production date or batch number.
The main specifications from Queen Battery QB14500's datasheet:
Nominal capacity: 800mAh
Minimum capacity: 780mAh
Nominal voltage: 3.7V
Standard charge current: 400mA (0.5C)
Max charge current: 750mA (1C)
Charge end voltage: 4.20V
Max continuous discharge current: 1.6A (2C)
Discharge cut-off voltage: 2.75V
AC impedance at 1KHz: ≤60mΩ
Pay attention to the nominal capacity - it's 800mAh, not 700 as printed on the heat shrink tube.
Measured DC IR at 800mA in fully charged condition was 51±7mΩ (measured using EB Tester Software's Resistance test feature).
Measured weight of the tested cell was 18.17g and the actual dimensions - 14.0×49.3mm
Capacity test results:
At 0.2C/0.16A QB14500's capacity is noticeably higher than 700mah - 786mAh. I think 86mAh is a good difference for such a small cell. At 2C/1.6A this guy showed almost 650mAh and the curve still looks good though i'd prefer to not go above 1A.
Queen Battery QB14500 surprised me a lot. I didn't expect such positive difference in capacity. All the curves look excellent and the only disadvantage i could name is the 2.75V discharge cut-off voltage which means that you should carefully choose the BMS.
Here is the video version of this review:
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