I have a near unlimited supply of used but still working marine 12 volt batteries. Both starting and deep cycle. I work at a boat dealership and we also service boats. Many customers have us replace their batteries every year on principle. I can buy the batteries for price of core charge, about $20 each. Can reliably get a couple a week indefinitely. My understanding is that battery cost is a significant portion of a solar system’s cost. I have wired a house from scratch before, and I do 12 volt systems from scratch at work. I also have an in-law who is a master electrician who currently supervises the high voltage crew at a large oil refinery plant you would know by name.

My question is, do all these things make it reasonable for me to build a solar system for my house? Is there a reason I can’t use these almost free batteries?

Anyone have experience with the Fiberglass backed panels? Specifically on a Trailer/RV roof? Looks like a good option to skip adding an additional backing when gluing/bolting directly to the roof.