Twenty-two years ago when we installed our system, it was one of the first in our area, and no one made a control panel to regulate the charging of the batteries, etc, so Windy Dankoff (who subsequently started a company that makes the best RE-friendly water pumps out there) designed a mad-scientist affair made of seemingly spare parts screwed down to a piece of plywood; last year I finally replaced it, and the replacement looks like a stereo speaker with a digital readout, and should make the batteries last years longer.  Our solar panels are huge compared to what's being installed today for the same capacity.

But the batteries?  They're exactly the same.  We're on our third (I think?) set of batteries, but they've all been basically the same, lead-acid batteries that have to have water added periodically, won't last forever, are extremely heavy, and are toxic to manufacture (although the recycling is pretty decent).  Since the sun doesn't usually shine at exactly the same time we want power, solar is going to stay on hold until someone figures out how to store it better than this.  It's fine as a grid-tied system, producing energy for the grid during the day and drawing from the grid at night, but that inherently limits the percent of our energy that we can ever hope to get from solar.

Maybe the answer is to partner it with other types of RE that have different limitations.  That said, no other type is as clean, efficient, and maintenance-free as solar, so it will be hard to ever get enough of anything else to make up the deficit between demand  and solar supply at night and in cloudy weather.