I don't have batteries. We have net metering available to us here with our electric company. So I store energy on the grid during the day and take it back at night. Our only risk is outages at night, which really don't occur very often in the 5 years I've lived here. I'd say our total outage even with all the hurricanes and storms has been 4-8 hours.
As far as system, I have Enphase Micro Inverters, Zeus SP460 Panels, Eaton Load Center, and my charger is Emporia. I also have a Tesla Wall Charger on the system.
Like you I'm also hoping I can use my R1S as battery backup in the future if needed versus buying home batteries.
Thanks. Interesting stuff for me to hear from real people, not spurious zealous posts to various solar forums.
The last outage here in Silicon Valley lasted four days for us, longer for some other areas, when a huge storm marched across California. It's basically a third world power infrastructure except we're paying very much first world taxes …
At least in California, where electricity is a government sanctioned racket, selling power to the elec co. is at a price lower than the purchase price. Net metering in CA is now something like 75% margin on top of cost of production, so their "sell" price might be $0.55 and their "buy" price would be $0.12. There's also TOU to factor into the actual slippage in buy-sell price. Fortunately I'm in an earlier net metering pricing plan that is a much tighter bid-ask spread.
While a 25% "discount" is something, it's pitiful that regulators allow this racket and actively discourage users from participating in grid stabilization, reducing coal and gas emissions at power stations … just so that one of the most corrupt corporations ever to have existed is able to profit at every turn, even while complaining of having no money to upgrade their antiquated grid (a grid that has a history of starting wildfires when it fails, falling over on windy days …)
We're using between 40 and 100kWh just with the EVs and three drivers. With maybe 8 hours of near 100% sun exposure, we're generating maybe 50kWh per day. That will triple as I build the expansions to the PV and add a turbine. The net metering plan is fixed to the original 8kW system, so the most I can sell back to PG&E is their notional max output of 8kW for 8 hours of 100% sunlight or about 64kWh, which I'm yet to achieve, so I don't know what happens if I ever attempted to shunt more joules back into the grid. I don't even know exactly how they calc the sum of power when the meter is "going backwards" … they seem to keep it all arcane and the people on the support phone lines are oblivious.
Anyway, my napkin math says the Franklin WH batteries will pay for themselves (after the 30% rebate, they're about $20K for a measly 38.4 kWh while I'm expanding with generic batteries to match the daily production of the solar array, which will get a wind turbine when I get around to it … lotsa paperwork for the govt to "permit" one to run a wind turbine) in about 5 years.
Given the two or three EVs charging at home plus work-from-home plus various creature comforts add up to $1000/month … cutting that bill to about $300 or saving about $8K/year, the whole system (solar, battery, generator, EV charging) will break even after about 5 years. I could spreadsheet it out, look at the return on investment of that capital invested vs that reduction in monthly cashflow going to investments and that would probably stretch it out another 2 years for a real breakeven.
I find this all quite interesting – as you can tell from the length of this post – striving for self-sufficiency in all utilities (water tanks, septic tank, now expanding the power generation capacity to deal with the EVs) but it seems absurdly complicated (and predatory if you just take whatever the solar companies would like to sell with unfair "deals" …)
I'll probably up the PV array with newer technology inside five years anyway, just for efficiency, plus the turbine outputs are huge – that technology keeps advancing, we're a long way from the old windmill appearance – so that will rejig the ROI curves.
As much as anything the whole system I've built is to "green" the EVs and provide fault tolerance for the local grid that is completely unreliable.
