Here's a chart I used for a company here in Ohio for the actual cost over 5 years. Not too bad at all after factoring everything in. As for maintenance they are relatively simple. Keep them clean and wiring is just as easy to maintain as any other exterior high voltage lines. But as you said,battery tech REALLY needs to improve before it can be utilized fully. If I was to do it at my home I'd get enough panels to power my home and power an electrolysis tank to make hydrogen to power a generator at night and hopefully in the future,my car.