Capacity test: Queen Battery QB18650 2000mAh 20A high-drain cell which surprised me

thunderheart

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Original article: https://www.thunderheartreviews.com/2019/08/queen-battery-qb18650-2000mah-20a-test.html

This is the 3rd 18650-size model in Queen Battery's lineup. I've already tested the 3000mAh low-drain and 2600mAh mid-drain ones. This one is rated at 2000mAh and 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 25±2°C. To be sure in results i've done each test minimum twice (usually 3-7 times).


Queen Battery QB18650 2000mAh 20A

The heat shrink tube tells us only the model, nominal capacity, max discharge rate and nominal voltage.
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The main specifications from Queen Battery QB18650-2000 datasheet:
Nominal capacity: 2000mAh
Minimum capacity: 1900mAh
Nominal voltage: 3.7V
Standard charge current: 1A (0.5C)
Max charge current:
0<t≤10°C: 0.4A (0.2C)
10<t≤20°C: 1A (0.5C)
20<t≤45°C: 2A (1C)
Charge end voltage: 4.20V
Max continuous discharge current:
-10≤t<0°C: 10A (5C)
0≤t<20°C: 15A (7.5C)
20≤t<60°C: 20A (10C)
Max pulse discharge current: 30A (<1s)
Discharge cut-off voltage: 2.75V
AC impedance at 1KHz: ≤20mΩ
Weight: 42±2g

Cycle life:
After 300 cycles at 1A charge/20A discharge (0.5C/10C) the cell should have ≥80% of initial capacity.

DC IR at 2000mA in fully charged condition was 16±2mΩ (measured using EB Tester Software's Resistance test feature).

Measured dimensions: 18.2mm (diameter) × 65.2mm (length).

Measured weight: 42.97g.
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Capacity test results:
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Just look at that! QB has again underrated it's cell by 200mAh)) They are crazy! This is a real 2200mAh cell but they sell it as a 2000mAh one... All the way up to 15A it's capacity stays higher than 2000mAh and only at 20A it goes below for only 2mAh (!!!). The curves are as beautiful as was my ex when i met her!


Verdict

This guy is a 2200mAh cell with excellent high-drain performance! The only disadvantage i could mention is its 2.75V discharge cut-off voltage but i think most of us configure their BMS to cut the discharge at >3.0V/cell.

Here is the video version of this review:


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