Really, didn't know the rapid disconnect doesn't apply to ground arrays. Why would a ground array be treated different than a roof array?
RSD is just fireman safety, if they're walking on the roof and hacking holes. So the requirement is segmenting array so < 80V. Possibly a wattage per section limit as well.
AFCI also required only if on the roof. So many connections to go bad, and many fires have occurred. Read about Walmart/Solar city.
Yes, that is my thinking. I've been looking at SMA and Fronius.
SMA inverters have a feature "Secure Power" to manually enable up to 2000W AC direct from PV if grid is down. Might be handy.
I think I'd rather buy a few extra panels, they are cheaper than I had expected. I've got a list of things a mile long that have to be done once or twice a year, I'm reluctant to add another one.
I didn't mean manual adjustment, just fixed orientation to optimize winter production. But only if you need the production to be reasonably high in winter.
When we bought the generator our electric system was like a third world country, it was off all the time. They upgraded a bunch of stuff over the years and now a power outage is a rare event, but the generator is 22kW so it will run the whole house and barn stuff if we need it.
Big generator. Surges like that could be supplied by a battery inverter, with the generator only running occasionally.
But you could add them. I put AGM batteries at $0.50/Wh over their lifetime. Maybe FLA forklift batteries would be half that. Commercial lithium batteries (like LG RESU) I think are also around $0.50/Wh. Higher price upfront, longer lifetime. DIY LiFePO4 looks like it is around $0.05/kWh. All those only if cycled enough times to wear out, which isn't likely for grid-backup.
Some inverters like SolArk I think you can start out as grid-tie and maybe batteryless backup, then add batteries if desired.
Sunny Island, Sunny Boy Storage, Outback Skybox, Schneider have battery inverters that can be added on to a system of grid-tie inverters which support frequency-watts. Some of those may be hybrid inverters that also take PV input, or others can work with DC coupled PV.
Depending on time of use rates (you may be forced onto those when you get PV, and they may become mandatory for everyone in the future), you might want to do peak shaving. Avoiding consumption at peak times is best, but some products are meant to charge battery off-peak and supply from battery on-peak. However, the commercial offerings I see cost too much compared to the spread in rates. Only DIY LiFePO4 (or "explody" repurposed EV batteries) seem cost effective. Future building codes are expected to require batteries (other than lead-acid) to be UL listed, but allow repurposed EV if located at least 5' from the house.
Wow, never thought about used panels. I'll have to look into that. Do they come with any kind of warranty?
SanTan gives a 1-year warranty on used panels. Some have UL stickers removed, some intact. He also has some surplus with manufacturer's warranty. Prices range from $0.12 to $0.50/W. Some people have bought new 500W panels straight from China. Don't know how that is going with the latest trade wars.
Some panels have had high failure/degradation rates, and some have worked fine for decades. So quality matters. Usted/tested at least means they've stood the test of time.
My system was strictly grid-tie to start. I finally added Sunny Island (there are liquidation deals due to DC solar bankruptcy.) My battery is relatively small, enough to run the house one night if grid goes down. During the day it provides starting surge for motors like A/C, and commands GT PV to adjust output to match load. Battery backup isn't cost effective, but it is convenient. Of course it can be done very small just for communications equipment, or sized to run for days without sun, or just to run major loads when the sun shines like mine.
