murphys_lawyer | Gone Solar (Reply)

Seeing as it’s been four months since I last posted here, I thought it was time to bring you up to date on the solar panel and battery installation, and the results.

It didn’t get off to the best of starts – the scaffolders turned up on 26 February, took one look at the house, sucked their teeth and went “It’s taller than three meters, innit?”. This being the case, they put up what they’d bought to halfway up the first floor and left muttering dire threats against surveyors who only use Google Bloody Maps. I didn’t point out this was slander against the surveyors, who turned up in person with a drone and a laser thingy that does those trigonometry problems you got in school to find the height of things like, you know, houses. Anyway, the scaffolders came back a couple of days later to finish their part of the job (and did it well, to their credit) in time for the actual installation on 1 March.

The installers told us to expect them between 9 and 10 AM, but must have had a headwind up the M1 because they turned up at 8.45. After showing them where the mains switch and fuses were, and making some suggestions where to fit the inverter and battery outside (current regs require indoor fittings to be in a room with two exits, and the old coal hole in the cellar didn’t count), we left them to it. They finished by 1PM, handed over some paperwork, and left to go back to London.

Here’s some photos. Click to enlarge if you feel so inclined.

Panels on the South roof. That’s a lot of scaffolding.

Panels on the East roof. If you click to enlarge, you can see the anti-bird mesh between the panels and the roof. This stops anything nesting or sheltering under the panels, which does them no harm but can leave a lot of guano on the tiles.

The battery (10kW) and inverter (3kW).

Where the power goes into the house, near the mains switch.

All the electrical gubbins. There’s a smart meter at the bottom and a comms box on the right. I’ll post again on how they’re working when they’ve been running for while longer.

After running the setup for about a month, our electricity bill has come down by just under a half of what it had been the previous month. This isn’t just due to the days getting longer: we had an exceptionally good spell of fine weather and clear skies which gave us a 10-day period where the panels and the battery supplied all the electricity we needed. Among other things, this let us do a serious amount of washing and dry it on the lines in the garden rather than the rack in the kitchen, and still leave the battery topped up at 100% at sunset.

A system graph from 10 April. The pale blue line on the top graph is the solar power collected, the red line power consumed. You can guess when we ran the washing machine. The bottom graph is the state of the battery, which starts and ends the day at 60% or thereabouts.

So other than the scaffolding, everything went exceptionally well, and I’m glad we eventually decided to do it. As I’m typing this up at about 10PM, the battery’s still reading over 80% full which will take us well into tomorrow morning. There’s some heavy clouds and rain expected here for a couple of days next week, but this was never going to be a fully off-grid setup. If nothing else, we may soon be selling our surplus power back into the grid – not a lot daily, but it will all add up.

Oh yes – the scaffolders took nearly two weeks to take it all down again. I have a sneaking suspicion we were being used for temporary storage…