Solar cell phone chargers use solar panels to charge cell phone batteries. They are an alternative to conventional electrical cell phone chargers and in some cases can be plugged into an electrical outlet. There are also public solar chargers for mobile phones which can be installed permanently in public places such as streets, park and squares.
This related to engineering because when it comes to chargers, electricity plays a part right? Well.. when somebody is thinking about making a new charger idea they have to plan and figure out how they’re gonna make it, how its gonna work and maybe how much it will cost to construct. This solar powered phone charger is being man made, maybe even by multiple people.
http://esfstream.com/solar-panel-charger/
