Please turn on the battery switch to position "I" for charging. The LED indicator of the AC/DC charger will change from Red to Green if the battery is fully charged. 12V rechargeable Lithium-ion Battery Pack is designed specifically to integrate with our Light bars, Flexible LED Lights, or most 12V DC electronic device. Technical details: Built-in 12pcs rechargeable lithium ion battery cells in 3s4p. Capacity: 3.7V 38400mAh (=11.1V/ 12800mAh)/ 142.08Wh (12pcs 18650 cells, the capacity of each cell is 3200mah at 3.7V) Input: 12.6V/2A Output: 12V (voltage range is 12.6-9V) /6A Max. 5V/2.4A Max. Weight: About 730g Package content: 1x DC 12V Li-ion Battery Pack 1x DC5521 Male to Male Power Cable 1x 12.6V/2A AC/DC Charger NOTES Do not use the 12V lithium battery pack in places with high humidity or where it may be exposed to wet. Do not modify or disassemble the power bank. Do not throw the 12V power bank into fire or water. Do not place the power bank during charging on flammbable materials such as in the bed or carpets. No long-term placement in a low voltage state. In order to extend the service life, it's suggested charge every three months if long term storage.