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The capacity of this power bank is stated to be 26800mah (99.1Wh). After fully charging the item I used a USB meter to measure the cumulative discharge current and the cumulative current to recharge. The values were 9875mah for discharge and 13650mah for recharge. Using the nominal voltage for USB of 5 volts this works out to about 68Wh. Converting to mah capacity using nominal lithium ion voltage of 3.7 gives 18000 mah. For comparison I tested a 20000mah power bank using the same meter and load. The cumulative discharge and recharge current values were 11640mah and 18776mah. Comparing the discharge cumulative currents of the two power banks it would appear that the capacity of the QTShine power bank is about 17000mah.