Where there is sunlight, there is electricity.
In many countries, the sunlight is very sufficient. So solar products are very popular in market. Taking solar power bank for example, solar panel on power bank can charge battery inside under sunshine and store energy during daytime.
There are two input with 5V 2A, and dual output with 5V 2.4A, so smart phones or ipads could be charged fully in a short time.
3w LED lamps would be a great helper during weekend family camping for lighting.