Now I have seen everything!!!!!!

My brother fell for that ****.
Got panels so he wouldn't have an electric bill, then financed it for 20 years so his financing is as much as his electric bills were, and when they're paid off, they're wore out.

And you don't get off-grid power unless you buy the batteries. You're just helping the electric utility supply someone else and you have to pay a fee for that.

I told him that $25,000 divided over his $120 electric bill every month meant that he'd not be ahead for something like 17 years, but he didn't listen. And that doesn't even include interest.
In your calculation are you making the assumption that his electric rate will not increase over the next 17 years?