Designed with the never-slow-down, everyday user in mind, Brunton??â??s Heavy Metal??â???¢ 5500 has sleek, urban aesthetics. Robust, lightweight and always there when you need it, the Heavy Metal??â???¢ 5500 is perfect for the truly power hungry. High-grade Lithium polymer cells charge faster and last longer; no memory and minimal discharge; 1000 cycles at 80% capacity. Charge time: USB - 6 hours, AC/USB - 6 hours, SOLARIS?? 4 USB - 7 to 8 hours. Power storage capacity: 5500 mAh. Output: USB & MicroUSB. Power output: 2.1 AMP & 1 AMP.