With regards the video, sometimes you can overthink it, then not even bother and maybe in the future regret it.
- My first 4kW system was a no brainer, even without FITs it would have been economic.
- My second DIY PV system + battery system was very expensive and at the time totally uneconomic. It was just a techy thing to do.
- My third DIY PV system was cheaper but still slightly uneconomic. I was driven by a wish to see how low my leccy import could go.
Some of my PV installations are questionable, I have some panels on a severely shading roof, NE roof, almost flat NE shed roof, and a couple on walls or facades.
I was strategically adding as much capacity as I could wherever it would fit and not bother too much about the economics. 10 years later, everything I have installed has turned out to be the best thing I have ever done.
Why ?, because 10 years ago I did not have,
1) Heatpump
2) Hot water tank
3) Storage heaters
4) A first EV
5) A second EV
6) Induction hob
My leccy import dropped from 6000 kWh (in 2010 before solar PV) to a low of only 700 kWh (2018). But after switching the gas boiler off in April 2021, my import is higher than before PV, up to 10,000+ kWh and I now need the Ripple WT1 + WT2 to offset that.
Going back to his video most I agree with, some not or to a lesser extent, but a list of things I have learnt over the years is,
1) Go as big as you can from the outset, even if it means borrowing money.
2) Batteries are now an almost must, especially if you are going large with PV, you can always start small and add more later if buying modular batteries.
3) You can connect more PV to batteries via a charge controller without DNO permission.
4) If your string inverter does a global peak MPPT function for shade management, then Solar Edge does not give you much more advantage.
5) If adding the odd mismatched panel here and there, then individual TIGOs work very well with almost any string inverter.
6) A ground mount in the garden is officially a ladder store, potting shed or a similar building.
7) North facing panels generate almost as much as a south facing one if its cloudy.
8) Flat roof panels outperform anything in cloudy conditions.
9) Wall mounted can outperform when the sun is low in the sky.
10) Get a smart meter and move to a TOU tariff.
11) Get your main fuse upgraded to 100A and your meter tails to 25mm if either are lower spec.