Originally posted by gaweidert Are you going to be storing any energy on site in a battery bank at your house? If not, when the grid goes down, it shuts off the feed from the panels and you sit in the dark too. The panels are still working, but the energy just goes to waste.
Yes, I am going blind trying to figure out batteries. The second reason to get batteries is our electric rates, which go up in the afternoon and evening. Batteries will save me money by charging when the sun gives me more power than I can use. Then later I can pull from the batteries instead of the grid. Also the utility buys my excess power at 15% or less of what it sells me power, so I have a big incentive to keep what I generate.
Quote: Look up Will Prowse on Youtube. He has a few different battery rack systems installed in his garage. He is great at explaining how it all works and his battery reviews are awesome. The guy is a natural teacher.
I have watched a lot of his videos and am almost confident enough to build my own batteries. His best advice is probably if you don't feel confident, don't do it. He does explain a lot of details that suppliers often bury way down in the technical data.
Quote: As the panels heats up they get less effective. Is there any ventilation under the panels to help them keep cool?
This is a very common question with the GAF shingles, and they don't quite answer it. What they say: their efficiency is competitive with very good panels, around 22.6%. But that's at ordinary temps, so who cares. Then they say the panels operate up to 122F, better than good panels. Again, a nice number but a lot of places can see 100F air temp in the summer, so 122F on a roof isn't that much higher. They did check and add attic ventilation which they say is now well within design parameters. I have seen This Old House projects where the shingles were floating on 1x2 battens with a matrix underneath. I asked if they wanted to do that and they said no. They do have a couple of warranties on lifetime and power production, and all of the promotional material says they designed the things to be nailed down to plywood like a regular shingle. I would like to think they've tested this theory. Maybe they are protecting their ideas that get it to work. If it doesn't, that's where it'll fail.