Took few days to build it since its a 12v 1.5amp, to calculate the current from 3.7 to 12v ive used a Dc to Dc stepup module LTC1871 booster module. Also it have 3.7v 18650 2500mah 4 batteries total output power of 10,000mah and power bank support, battery level indicators, Voltage indicators, torch and a Fan that supports 2900rpm.
