If you are on the grid, you probably want a 'grid tied' system, not batteries. A grid tied system allows you to sell your excess energy back to the utility company, while using the grid to draw energy during dark hours. This makes the most economic sense. If your cost/kwh is high, as mine is in California (>$0.20 on average) your payback will be less than 10 years and thus makes sense. My 6.5kw system produces more than $3500 per year. No negative sonic effect on the audio system.