Could you summarize your previous use, the solar/battery setup (I know pictures speak a thousand words, but I don't fully understand the language), and how the decision was made for 5 PWs? Is your utility service 200 amps?
I use an large amount of electricity (3383 kwh last October, electrician says (not sure if meant to be truthful, I later fired him) I have a 600 amp feed although my meter is 400 amps) and have had an installer suggest ~ 17 kW solar + 6 batteries will do 80% of my use. But those numbers were based upon previous owner's use, not mine .....
There is no easy answer to your question but here are some thoughts.
I have a 400 amp service with 2 200 amp subpanels. One sub is just the house. The other sub has all my heating/cooling which is all mini split heat pumps. (this is important compared to if one heats from something else)
Interesting you say you have a 600 amp service, but only a 400 amp panel. I would assume might as well assume you only have a 400 amp service unless you are changing your main panel?
This whole thing about use. IMO, this is far from the first questions one needs to ask. (As an engineer, I love to do all the what if questions)
First thing I would have folks think about is how much money do they have, want to spend, and for what goal. IMO, there is NO ROI that is worth putting on solar and batteries. Again, not the way I looked at it!!
Then one has to ask how long one is going to stay in the house.
If one has tons of money and into the green stuff, great, spend the money, drive the EV, but again, do not think about ROI.
Another question is what is ones tax situation. There is the ITC of 26%, but only if want has taxes to pay.
Another question is does ones power have TOU rates? What are ones electric rates.
How often and for how long and when does ones power go out.
What percentage of ones home is electric. Makes a huge difference on things to think about. What climate does one live in? Cold, hot, snowy, etc.
What sun does the location get? Angle? Shading? Etc.
Would a generator be a better cost flexibility option?
Once one has the answers to the above questions, then one can decide what next steps if any towards solar and or batteries make sense.
From a pure dollars where I am in Calif, I believe having lots of solar is the best first step. Simple to do and the best balanced cost structure here under TOU-c.
Now, with batteries, it looks like if forces one here onto TOU EV2-a which with peak being like 3 times non peak, totally means one has to look at when power is used. In some ways a pain in the butt.
Another thought on batteries that I have found it is not how many you have, but how quickly can they be recharged. I am dealing with this question now.
The recommendation is At least 4kw per PW, and depending on how effective the solar is, and when you need the power, this maybe way to low from what I have seen.
So, as you can see, IMO, there are tons of important questions one really needs to answer before ones starts spending money, unless money is not an issue.
