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NEW PANASONIC NCR18650PF Module Capacity Test

A project log for A 110 kWh Powerbucket

The lead-acid batteries of my off-grid solar system are dead. I will replace them by a 18650 batteries stack housed in a big wooden box.

Michel Kuenemann 08/20/2017 at 04:360 Comments

I have run a charge/discharge test on a module made of 70 brand new PANASONIC NCR18650PF cells. The cells were purchased at NKON in August 2017.

The measurements were made with my modular Lithium Battery Manager used in "Discharge Mode"

The parameters were the following:

ParameterValueUnit
End of charge voltage4.1Volt
Charging current10Ampere
End of discharge voltage3.0Volt
Discharging current - whole module10Ampere
Discharging current - one cell143milli-Ampere

It took approximately 16 hours to discharge the module down to 3.0 Volts  and the results are the following:

ParameterValueUnit
Module capacity180Ah
Capacity per cell2570mAh
Restituted energy - complete module656Wh
Restituted energy per cell9.37Wh

Conclusion:

The PANASONIC NCR18650PF cells are rated for 2900 mAh when charged up to 4.2 V and discharged down to 2.5 V. Taking into account that the end of charge voltage in my case was only 4.1 V and the end of discharge voltage was 3.0 V,  the measured capacity of 2570 mAh is really great. This also proves that the batteries sold by NKON are guenuine PANASONIC cells.

The following curves show the last hours of the test

Module equipped with the Modular BMS:

I will perform the same test on a module which as made approximately 250 cycles in my solar system.

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