About 18650 battery: The minimum discharge stop voltage of 18650 battery is generally: 2.75V. Under normal circumstances, when the voltage to 0.875 times the rated voltage (3.24V) It should be , and then continue to use, the voltage will drop , there may be over-discharge and damage, affecting the life. (Recommended discharge termination (The voltage is set to 3.5V) The charging voltage is generally: 4.20V-4.3V/4.35V. Measurement time calculation: Assuming that the battery capacity is 2000mAH, the discharge current of this tester is about 500mAH, (2000:500=4), and the measurement time is about 4 hours about. Please note: Different batches, product appearance and color may be different, does not affect the use Product name: 18650 lithium battery true capacity tester Display accuracy: 0.1 Measurement accuracy: 1mAH Power supply voltage: DC5~12V/18650 battery power supply Standby current: 5~7mA Discharge current: about 500mA Load power: 10W8 Appearance size: 110 x 80 x 25mm Installation size: 72 x 53mm Installation aperture: 3mm Model Number: battery capacity tester Application: battery tester : Battery Capacity Tester color:Green Material:PCB Package Contents: 1 x Tester Module Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.