Plug in solar

TroubledTarts

I haven't read the details fully but is a G98 required from 27th August under the new laws?

Ectophile

https://forums.moneysavingexpert.com/discussion/comment/82080866#Comment_82080866

If it's a type approved "balcony" solar system, no. 800W is considered to small to affect the grid.

TroubledTarts

https://forums.moneysavingexpert.com/discussion/comment/82080920#Comment_82080920

Thanks that's what I thought I just couldn't be bothered to read the law passing info

Qyburn

https://forums.moneysavingexpert.com/discussion/comment/82080983#Comment_82080983

The actual law says nothing about G.98, all it does is permit a compliant system to be plugged in.

Maybe it'it's the 2026 revision of G.98 making the exception. I haven't been able to find that, even the ENA library only offers the 2025 revision.

Newbie_John

@Scot_39 , sure 3kW kettle will still be costly, but you can replace it with 600W kettle:

https://www.amazon.co.uk/Quest-Portable-Lightweight-Worldwide-Protection/dp/B01LXGNI8V

On sunny day at peak that should be a free cup of tea.. though it will take 5x longer.

lohr500

https://forums.moneysavingexpert.com/discussion/comment/82081894#Comment_82081894

You may have to limit your tea drinking to 11:00 to 14:00 hours though!! Or use that time window to boil several lots of water in the 600w kettle and fill thermos flasks. And don't plan on drinking much tea between September and March.

I've built my plug in system with two nominal 450W panels and a twin input 800W micro-inverter..
I have the panels aligned with the PVGIS Azimuth recommendation, but the elevation, at 20dg, is not optimised..The panels have no shading/obstructions.

Through the gloriously sunny days in June and July, peak output has only got above 600 watts on a few days and then only for a couple of hours or so around midday. Any sign of clouds and the output drops significantly.

Newbie_John

Im sure there are Winter kettles with 100W power 😂

Scot_39

https://forums.moneysavingexpert.com/discussion/comment/82081979#Comment_82081979

I just checked Amazon - you can certainly get little one cup hot water heaters that look a bit like an insulated cup - that are around 300W for travelling.

I used to have one of those little bare element heaters you put in a mug - that was around 500-600W - but you then had to have space to safely place the hot element after heating the water.

Scot_39

https://forums.moneysavingexpert.com/discussion/comment/82081966#Comment_82081966

Thanks for that sobering reminder that location is key.

I think I'd maybe struggle too.

I'm in a compact mid terrace and house facing WSW - with nowhere to put panels at front - that gets most of the sun in the afternoon.

Maybe half my small back is in house shade by mid afternoon.

I did think about possibly the shed roof (c2.7m wide x2 deep x2.1/2m tall - so tilting slightly to rear - away from afternoon sun) - but it might violate some height planning restriction. Shed already sits a little proud of the 2m fencing at the front. And to be honest it's not that strong a shed. 30-40kg for two 400W panels,and then at that if caught in a gale might be too much for it.

Almost any ground install would have shading problems - at least for part of the day.

Shading and mini invertors ?

Does anyone know how well mini invertors cope with mixed panel output - for part shade scenarios ?

From memory when looked into it - roof solar has effectively either multiple "channel" connections - some others go to i guess panel level microinvertors - for part shaded applications to stop interactions ?

I did see some half sized panels - 12V / 200W on one site - but wasn't sure how that work with a plug in invertor - given other panels higher voltages - and to be honest they didnt seem that much cheaper - in terms of reducing pay back.

I think I'll wait to see what happens after Aug rush is over - pricewise and tech wise.

Given I'm looking at 10+ years pay back - without battery.

And appears that would add - potentially more than double to costs - even if used a chargable power pack and powered say PC/monitor - 200-300W depending - or TV off of it's sockets in evening. But even some of those -e.g. Ecoflow delta add well over £1000 for a couple of kWh store. To save essentially 50p a day on import if charged by solar. so again that model - even ignoring cycle losses - payback c8 years.

lohr500

@Scot_39 Regarding shading and mixed panel output :

When I started my plug in solar journey I was going to use the Hoymiles 800W HiFlow single string/input micro-inverter as sold by City Plumbing.

But @QrizB kindly pointed out that with two 450W panels connected it would have been at or over its maximum peak input specification when the panels were workig at high output.

So in the end I went for an AP Systems micro inverter which has two stings/inputs, with each string capable of handling up to a 720W panel. The micro-inverter still limits output to 800W even if input exceeds this.

The added benefit of a twin string input micro-inverter is that it will handle shading better, especially if a two panel system has the panels in different locations, with different amounts of shade. Reduced input from shading on one of the panels shouldn't drag down the other panel if that isn't affected by shading.

My two panels are mounted side by side due to the nature of the flat roof mounts I used, so other than passing clouds, they are pretty much running at the same output through the day.

Once the kits start to hit the retaillers it will be really interesting to see what the specifications of the panels and micro-inverters are.