Purchased via Amazon. Described as "12 V 3000mAh".
Weight 195 grams. Form factor would tend to indicate 3 x 18650 cells.
Power pack was fully charged before each test.
Measured capacity 2389 mAH. 80% of rated capacity. Discharge curve shows that the "12 V" output is unregulated.
Ramp test shows that the output Voltage falls as the current rises. When the current reaches 3 Amps the terminal Voltage is 11 Volts.
The powerpack does not meet its specification.
Item will be returned.