For sustainability and environmentally friendly designs, the solar-powered smart backpacks are your better option. They draw in power from the sun that will ultimately charge your device. However, some customers have run the risk of it not charging devices properly, taking a long time to charge, or if the sun isn’t bright enough, they are finding the solar bank isn’t charging. If you want quick efficiency and already own power banks, smart backpacks compatible with them may be the best option for you.