... indicators:1, using high-efficiency monocrystalline and polycrystalline silicon solar cells , solar energy conversion efficiency as high as 16% or ... battery by computer Usb or AC adapter about: 4 hours9, Backpack fabric:Polyester 1680D (customer specified) 10, Lining:Nylon 210T ... view the test video,please visit www.any-solar.com and link to http://u.youku.com/user_show/uid_hztjq Solar school backpack