My idea is simple.
To spread solar in rural Africa and elsewhere where access to electricity and Internet is limited. I wonder. Could the cost of a solar kit be partly payed by ads. The idea is that you store good music on a memory in the battery device with ads in between the songs.
If the music is good then people will listen to it and at the same time local and city businesses can reach out.
So the idea is to equip the battery device in a solar kit with a built in digital music player and upgradeable music. Perhaps the ads can be updated by the phone signal.