Step 5: The End Product
This is easy and inexpensive. Anyone planning a new construction home should really consider a 12v solar system just for whole house lighting. Beefing it up a little with bigger and more batteries (and appropriately rated charge controller) and a person could easily add DC outlets like these to charge practically anything that comes with a car cigarette lighter charger. Fixtures such as recessed lights, ceiling mounted lights, and the lights on fans could easily be converted to 12v dc with the use of a-type 12v dc LED bulbs. The fixtures could even be modified to use the different socket types of lower voltage LED bulbs. They are more expensive, but they also last longer.
It's easy to do and it's something the world should be moving towards as a way to ease strain on power delivery systems. Plus you'd have light even in event of a grid power outage.
Now go out there and save the world (and in the long run, your money) with energy conservation.