Efest IMR18650 3500mAh (Purple) 2017
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Official specifications:
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Rated capacity: 3500mAh
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Nominal voltage: 3.7V
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Voltage at end of discharging: 2.5V
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Max. charging current: 4A
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Standard charge: 2A
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Discharging current 10A
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Pulse discharging current: 20A
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Charging temperature range: 0°C ~ 45°C
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Discharging temperature range: –20°C ~ 75°C
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Inner resistance: 20mOhm
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Cell size: 18.5 (±0.2)mm x 65.2 (±0.2)mm
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A high capacity 18650 battery that can deliver a fair amount of current.
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The discharge curves shows nice tracking between the two cells. The battery has very low voltage at 20A.
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The battery gets very warm at 10A discharge current.
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At 15A I had to stop the discharge due to temperature.
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I also had to stop at 20A.
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Conclusion
The cell looks very good, it has lot of capacity and can handle some current, but I will not recommend it above 10A.
Notes and links
The batteries was supplied by Efest for review.
How is the test done and how to read the charts
How is a protected LiIon battery constructed
More about button top and flat top batteries
Compare to 18650 and other batteries