Beelbeebub

Yes We took each point in turn Wind lift (my main concern) - the location is very sheltered and the fixing method provides a very direct load path from the panels, via the shee metal to the main structural timbers, which are in turn specifically fixed down to resist wind uplift (in this case from the sheet metal) Ridge tiles - sheet metal mono pitch roof so not a concern. Even in a duo or hipped roof, the ridge flashing are screwed down rather than mortared on as a tiled roof, so no danger of them coming loose from turbulence. Rain and snow - care was taken at the eaves to make sure the run off the panels didn't 'over shoot' the gutter. Basically the lowest edge was stepped in about 2 inches. As there are gaps between the panels the runoff from the upper panels tends to fall through onto the metal roof anyway. Snow wise, other than making sure the dead load of the snow is fine we didn't worry. Snow is fairly rare here and the low pitch of the roof means there is little chance of big slabs sliding off to damage anyone/thing Wind noise - we get plenty of wind noise from the trees, there is little chance of wind noise being a regular problem. Any structure can generate noise in specific conditions. It's just a case of making sure those conditions are not the common ones. The 400mm rule of thumb is not a bad thing for retrofit to tiled roofs. But it shouldn't be allowed to become a golden rule for all circumstances - especially roofs specifically designed with solar in mind.

Thank you. I used a mini rail system. I can't remember the exact make, but I'm very similar to this https://midsummerwholesale.co.uk/buy/k2-pitched/k2-mutlirail-10-with-screws Fastensol and Renusol do similar. Basically short bits of rail with an epdm pad underneath. These get screwed to the top flat bit of the roof profile allowing the standard mounts to clip in. Effectively you are using the sheet metal profile as the rail itself. It was very easy to put up, especially as the sheet metal roofing was easy to walk on. I made (3d printed) some end caps to give the exposed rail ends a nice finish. I could stick some skirting round to neaten stuff up but I don't think I will have any bird/pest issues and it does allow for better ventilation. Visually being able to line up with the edges makes a difference. There was a fair bit of discussion about this as the guidelines talk of 400mm margins and the like but nobody could really find out exactly why. The best explanation was wind lift, so we took extra care to make sure everything was well fastened down and there was a good load path to the heavy foundations.

I wanted to do the same (make a roof out of the panels for cost. I went round the houses so to speak) with things like GSE trays and even rubber stripes between the panels. In the end I used trapizodal metal roofing (think industrial unit) as the waterproof layer. It seemed the easiest way to ensure watertightness. It's light (less than 25kg including panels and mounting rails), robust, easy to work on (no cracking or knocking tiles) and pretty long lasting. Industrial metal roofs easily last 25 years, often 30 or 40 (lots of units built in the 80's are still knocking about). The primary aging mechanism seems to be UV damage to the Pvc coating (don't get the painted finish) and that will be helped by the UV shading the roof. I didn't put a roof membrane under (because it's a carport) but you could easily. Then there are a number of systems that use self drilling and tapping screws (the same as used to mount the metal panels to the purlins) to mount little sections of aluminum rail or you could use full length sections (just costs a bit more). The panels then just mount as normal. The total standoff from the top of the trapizodal roof profile is about 50mm to the top of the panels. Of course it depends a bit on your roof design (complex hips and valleys or curves etc are harder) and overall aesthetic (work well on a modern building, not so much on a stone cottage in thr cotswolds)

My inverter has a big rotary dc isolator set built in - you turn that and the panels are disconnected therefore no load, then the mc4 connectors into the inverter can be removed with no issue (arcing) even though they are still at high voltage. I can't see how an external isolator helps there except that there will be zero voltage. Ultimately at some point with solar, unless you work at night or cover the panels completely you will have to work with live HV. The MC4's are crimped onto live wires at some point (yes, doing as much work on the disconnected system as possible is best practice, but you can't avoid some work on live bits)

You could wait for (hopefully) the position on grants for air to air systems to change for the better and then just install one of those. Our UK obsession with A2W systems is based on retro fitting to existing heating systems. As far as I can see the only 2 advantages A2W systems have is 1) *once installed* the emitter side of the system can be worked on by a regular plumber 2) it will retro fit into an existing wwt system *as long as the pipes and emitter are suitible* There is a possible 3rd which is some people prefer the heat given off by a wet system to a blow air system. This is particularly true of UFH. But if you are using fan coils that 3rd point is moot and even the 2nd point is fairly weak. Which leaves you with point 1. If you are comfortable with calling in a specialist to do work then that's sort of irrelevant. Right now not you need to find a specialist plumber to work on A2W anyway, so not much difference to call an air con guy instead.

I'm intrigued! Painting, I assume, is just normal airbrush painting like for cars etc. What is aqua blasting?

Also, I'm curious what you using the air for? I'm trying to think of a hobby that uses 7kw of compressed air! Is it for a pumpkin cannon?! 😁

Can I ask, how long for? Like 7kw of air all day or 7kw for an hour or so? I wonder if an 8kw 3ph inverter/battery would do you? Solax do one (x3 ies) With 20kwh of battery storage you could run for over 2h at full pelt without drawing anything from the grid. IIRC they feature a 2x overload for upto 10 seconds ie 16kw which should sort out startup currents

I was referring to the curtailment. The issue with gas setting the price most of the time may well be as you say. I've noticed that there is always 2gw or so of gas in our generation mix even when it seems it isn't needed. It just sits there in the mix even as interconnect, renewables, demand etc rise and fall. If that falls away we may well start to get cheaper elec, but that will have a knock on effect on renewables build out Still the point is, renewables are growing fast and promise cheaper electricity when we turn off the majority of gas. I do still believe we will need a fairly big gas capacity (maybe even more than now) to cover us for some of the winter etc, but running the UK 90% of the time on lure renewables and burning a bit of gas every now and then is a perfectly acceptable target for the medium term.

There are various plans, but they often run into local opposition I saw one local pressure group against some pylon lines using the "it will take valuable farmland and damage our food security" argument - which is clearly bollocks given the relatively miniscule footprint of pylons. There are arguments against putting pylons in certain places but they almost always boil down to aesthetics, ie people don't want to see them. That's fair enough, but at least put that argument forward (why should my view be altered for the national good) rather than BS ones.

I assume your flexi panels, charge controller and some small leisure batteries are on the van? You arrive at "home", park up. Go through your disconnect routine to unplug/isolate your flexi panels from your charge controller. You now have a van with no solar panels (as far as it's aware) running as though it is night time. i.e. off batteries. Unlock your little waterproof box, unspool the cables from your fixed panels - however many your controller will handle and spsce/money allows and go through your reconnection routine. Now your charge controller is hooked up to some panels, it doesn't care they are different from the van mounted ones, it just goes about it's business. Basically all the work you were going to do, except you just need to disconnect your flexi panels rather than have them in parallel.

This is true, but is a consequence of our grid not habug the right interconnections - it was.set up to supply power from a few concentrations of coal plants in the Midlands and North. Shifting power from thr coast is harder. Sometimes there isn't enough capacity to shift the power Solutions would be to beef up the grid, including some new lines. Grid scale battery storage to store the energy locally and then supply it when the generation is low Local storage (down to house level) will help sooth out peaks on demand but won't help shift the power out of high generation areas.

A battery system would allow higher instantaneous demand for periods of time without overloading the grid. 60a (14kw) could be upped to 90a (+30a, 8kw) with an 8kw battery system.

Ah I get it. Might in suggest, rather than trying to parallel them up, with the attendant issues, you arrange it such that when you are at "home" you totally disconnect from you van mounted panels and just use as many standard panels as you want, then switch over to the flexible for mobile use. You can make up for the loss of the flexible panels by adding a single extra standard panel to your ground array. Much less chance of issues. As mentioned the disconnection and reconnection needs to be handled with some care.

What's the max output of your controller? It looks like you have 3x 100w panels. That's less than the output of a single modern standard panel. panel, just buy one extra and bingiveaway/reuse the old ones. https://www.cityplumbing.co.uk/p/dmegc-450w-all-black-solar-panel-2mm/p/120106 £61 each for 450w. Under £200 to quadruple your capacity

On the pessimist view of climate change actions. https://www.theguardian.com/environment/commentisfree/2025/aug/20/voices-arguing-climate-crisis-action-is-a-waste-of-time-are-wrong TLDR: yes there's a ton of stuff to do and we need to move faster, but real progress has been made.

Which i addressed. If we had zero renewables and were fracking all day every day (which is the position of some in the political discourse) our electricity would be no cheaper and possibly more expensive. On the other hand, installing renewables offers the UK yhr chance of much greater energy independence. Sure we'll always need oil and gas for feedstocks and for situations we can't electrify (aviation comes to mind) but if we decouple our heating and transport (two big energy users) from gas and oil we'll be better off. And the most practical route to removing gas from our heating demand is Heatpumps.

The "we're an insignificant bit of world co2 emissions so there is no point in doing anything..." argument annoys me so much. 1)it's usually made by people who, a few breaths ago, were proclaiming how important and world leading the UK is. It seems we the nation all others shoikd look to for all sorts of things, except climate change. 2)the UK per capita emissions are around aboit mid pack. The real danger is if the vast numbers of people in developing nations who are currently emmiting less carbon per capita look at our lifestyle (cars, consumption, hearing, cooling etc) and think "I'll have some of that". If the UK and other developed nations are moving down it makes it much more compelling to say "hey guys, why not skip the high emissions part of the cycle and meet us at the low emissions phase" 3) renewable power is the cheapest power and the cost of power is a big driver of economic success.

Elec prices are tricky. On the one hand renewable electricity is pretty much thr cheapest there is. Solar is cheoeast, with onshore wind and then offshore roughly on a par with CCGT depending on gasmlroces at any given time. On the other, the high price of elec (effectively tied to gas) means there are big profits in putting in renewable capacity, and hence a big surge in that capacity. So our high prices are helping drive renewable. But also hampering the shift to HPs. On thing we could do is shift some of the so called "green taxes" from elec to gas use. My napkin calcs imply this would slightly raise gas and slightly lower elec, enough to bring the price ration from 4:1 down to 3:1 or even a bit better. At that point HPs start being cheaper than gas in almost all homes. Of course there would be pushback from people who already struggle.to afford gas heating. We would need to ensure there were mechanisms in place to prevent hardship

The issue with that approach is the generation capacity to replace gas on a. 1:1 basis would be vastly larger than to replace each kwh of gas heating with 0.3kwh of electricity generation.

There was a fair bit of discussion about the border, but nobody could come up with exactly why it should be there. The closest explanation was wind uplift, but if it's not on a roof ie just panels on a frame there is zero margin. We did fix the edges of the roof and the panels extra securely, plus we are in a fairly sheltered area - might not do this if we were on top of a cliff on the West Coast of Scotland! Regarding access, the central gap was left for exactly that, and access to the outer panels is safer from the sides anyway. My case is fairly specific but does show what is possible. I did look at using the gse system but cost wise this was cheaper and also easier to install. The pitch is only 12deg which loses a bit of output, but was done for aesthetic reasons plus it means the roof was safely walkable for installing the panels

This may not be what you're after, but I fitted my panels onto trapizodal "32/1000" pvc coated roof sheets - think industrial roofing. It's about as cheap as roofing gets and the panels fit really easily to the tops of the profile with small "mini rails". The trick was to have the panels go edge to edge and eaves to ridge of the roof, which I could do as it was a mono pitch (though it would work with a duo pitch). And, though it's not suited to every aesthetic or roof layout, it does work especially well on outbuildings (mine was a carport)

That's what an optimiser does, but I don't think the more basic bypass diodes are as effective (despite what the manufacturers claim). There's a video with someone testing the Neostar 3's which the manufacturer tours as being much more shade resistant - but shows if the shade is the wrong way, it doesn't work as well. I found this with a cheap 60w panel that keeps a tractor battery topped up. If you shaded it with a thin stick vertically you lost a bit under a 1/3 the output, but the same stick horizontally knocked it down to very little (like under 10w or something). As for minimum start up, half the array is 12 panels with is pretty much the maximum that a single string can handle on my inverter. IIRC the start up is 40v, which isn't even 25% of the full output Again, because I've wired it as 4 blocks it's really easy to switch between 2x12 (if I find start up voltage is a problem) or various 12 + 2x6 configurations which deal with different aspects of my shading issue (the tree tends to cause an issue with one corner, my house will shade the entire bottom edge, creeping up as winter advances) I don't propose to switch regularly, just a few times to get a feel for which one (if any) will give me the best (as in most suited to my needs) overall production.

My understanding is the built in bypass mechanism effectively divides the panel into 2 or 3 sub panels so is useful if a bit of a panel is shaded, as long as the shading happens to align with the sub panels but can't help if the entire (or most of) the panel is shaded. But dividing the array into 3 to use the existing strings is effectively for free (just a little extra cable) and the arrangement of 4 sets of 6 panels means I could always rewire the array to be 2 strings of 12 if I wanted.

Good question. We looked at that. The original layout was 2 strings of 12 and only the 3 corner panels of one string had a shading issue. The options were to add 3 optimisers - £150-300 Or to use the unused 3rd string to get around the shading issue. The panes have been wired up a 4 groups of 6 and the connectors brought down to an internal location where 2 of the groups will be connected in serial and the other 2 will get a string each. This will allow for easy rejigging if we want to and the location of the panels makes it very easy to add the optimisers later. The array is well oversized so i'm not looking for the nth degree of optimisation, but losing 1/2 the array until lunchtime because the bottom left corner panel is shaded would be a bit annoying.