Solar installed - what next? Musings and advice

Leaving aside the financials on the north roof for a sec (and the proposed extension), I don't think you have the capacity to do it (easily). You have 18 panels as you say on the south roof. Normally they are 40-45V each, meaning that (most) inverters max out with 12-13 panels per string. Since you have 18, I suspect that the supplier has set it up that both of your strings are used on the south aspect. So you would be looking at an additional inverter, or using optimizers, or reconfiguring the panel setup where you would have say 12 panels on the south aspect and 12 panels on the north one.

That 12 and 12 isn't as crazy as it seems though. You'd be in about 9Kwp, and that would be about the max with a 6Kw inverters. Yes, your right they won't produce much from Nov - Feb (but they will produce something), however you still have a fairly substantial south aspect of 12, and overall I think you will increase the number of months where you are self-sufficient. In truth in the summer, we have more than we need, so it's improving the situation for Mar&Apr as well as Sept&Oct that you'd be looking at. A little depends on the slope of the roof, the more shallow the slope the better. I haven't' run the math, but gut feeling tells me that it's a runner. Limited work required too on the electrical side, it's just really a panel provisioning and roofing problem.

As for the other musings, I don't know enough about installing 2nd inverters, etc, but I do suspect that you would need 3 phase, and then you would be able to export up to 11Kw (instead of the 6kw currently on 1 phase)

Are you out "da country"?

Our of curiosity, I ran the numbers for you

The 12-12 split is an "improvement" (loose term), but having seen the numbers, I'd probably pass myself. Generally adding North to the house is good, but in your case you'd be giving up a south panel to get 2 north panels and it's only marginal.

If you could reconfigure the south array to get in more panels (landscape instead of portrait etc) that might be the way to go. Even 2-3 panels would be cost efficient.

There is at least one user on here with 2 x 5/6 kW inverters on single phase and use functionality of inverter to limit export. Probably something you'd want to confirm with esbn to be sure?

Ugh Teslas 🤮

I'll take the i4 over any Tesla any day (yes I drove all of them)

I think maybe his point is that people easily lose the run of themselves as sell themselves the idea that they are making long term savings on these large investments in technology.

If I were to recommend anything when it comes to this tech - is that you need to remain level headed. Building a solar Moneypoint out the back might be the dream, but you'll never get a return or indeed break even. Not unless there is a radical policy shift - and that's a gamble.

I don't see it as a bad thing unless they spend too much and are facing into multiple decades of praying that stuff doesn't pack up in order to break even. By the time someone inherits the place anything they buy now will be old hat and obsolete anyway. Cars are generally also a terrible investment.

I can see how fellas would be inclined to fall into the trap of buying stuff in order to use up the excess power they're now generating. This is mainly down to the nonexistent feed-in tariff we are getting. The right job for fellas looking to invest would be a proper community run solar farm. It is unfortunate but unless we group together the elite in the energy sector & their government buddies will keep taking free power off our hands

The way things are headed now with power companies increasing their prices & standing charges every few months the off grid lifestyle is looking more tempting, with the availability of cheaper batteries you wouldn't even need gas for cooking anymore.

You wouldn't consider a Storage Heater for the same purpose? Could be much easier to setup, and run off the Eddi its set-and-forget. Putting near 10kwh in each day these days, and is taking the chill out bedrooms these nights.