Ronski

No I haven't, I have seen similar used on the roof of a new local building for what I presume is safety cables, the building roof is level with the cliff top path (Royal Sands Ramsgate) It was a local installer that told me they were about £50 each, I'm looking to put a system on a flat roof garage.

Here's some info you may find useful. https://www.singleply.co.uk/fixing-solar-panels-to-flat-roofs-why-we-recommend-an-engineered-solution/ https://www.nicholsonsts.com/products/rooftrak Apparently these are about £50 each.

I already have a 4kw array, installed in December 2015, it's roughly £1000 off paying for it's self. I'm waiting on one quote from a local installer who's actually been out for a site visit, and is willing to let me do some of the work. If it's too unreasonable, then I'll DIY the whole lot, with the help of an electrician. Plan is to run two 25mm SWA cables out to the garage, and divert the mains supply via the garage. Victron 8kva inverter, and 14.4kwh DIY battery, for whole house back up, with the addition of another 5kw of panels on the garage. Can add more batteries if required, and more panels if I wanted, but the last two roofs remaining are not ideal for solar. Only wish I thought of this back in 2002 when we built the extension, would of been easier to run in the cables.

I’ve been watching more of Andy’s off grid garage journey, and it occurred to me at the weekend, from a simplicity and cost point it view it would be better to use four MPPT 150/35 charge controllers, with three panels on each string. Whilst this won’t work as well as SolarEdge optimisers with regards to shading, it probably wouldn’t be far behind, problematic panels could have Tigo optimisers fitted if need be. This approach would reduce maximum usable power, as the new array and batteries would be just through the Multiplus II, which unless I went up a size (a lot more expensive) would be limited to 4kw output, but it’s not often we’d exceed that anyway. The existing array could be run in to the critical loads output, and thus both arrays would keep running in an extremely rare power cut, supplying power and charging the batteries. The fridge freezers (on their own circuit already), lighting and perhaps some emergency sockets could be run off the critical loads circuit. This would of course require two new cables from the garage. Would the Multiplus II be able to handle the existing 4kw array on the critical loads circuit and would we be able to use say 7kw of solar if both arrays was producing 3.5kw? What's you're thoughts on the above?

Yes I believe so.

If the sun's lower in the sky you'll need a steeper angle.

Perhaps I should glad the rear of my almost south facing house in solar panels.

That would be 40 amps total, not 80, you can't add up the +ve and -ve like you have.

@MrTWalesThanks. Mine will be within 1 meter of the edge, still not had a reply from the council.

@WilThanks, that was the second response after I phoned them. First response was to complete a G99 application, I then phoned them and the guy said to put it in an email, he seemed surprised when I said I already had and told him what reply I got.

Ok, back to wondering what the minimum install angle is.

I was aware of the issue as mentioned above, but didn't know what the minimum angle was, so thanks for clearing that one up.

Our cat would probably be scared of the pigeons! But there are plenty of others which aren't, but it was the main house roof that was the problem with pigeons.

I have a thread here which detail some of what you ask If the panels are all facing the same direction then panels shading panels will be an issue on your roof, it is on mine, mainly in the winter months though when the sun is low, even with the panels at a shallow angle. I modelled the garage/panels in Sketchup, and can then see how the shading is: The above is at 13:30 on the 1 January, the shading only gets worse as the day goes on, and in winter you need every bit of sun you can capture, days are short, the suns low, and not very powerful. The panels are at 15 degree's, and they are 1722 x 1134.

The east west thing is to get bigger panels on, with the panels all facing south, you need spacing to stop one row shadowing the next, with east/ west think of a flattened upside down W, so you don't need space between the panels so they fit better in the limited space. I actually like the appearance better as well, and another benefit is its easier to fit bird protection to stop those pesky pigeons nesting under there. I think there's two possible reasons for the 300mm gap, one is access, the other could be related to wind, but the panels on my main roof are about 200mm from the edge, so I don't think everyone adheres to it. I've had a hard time getting quotes as well, emails just deleted, silly prices, systems that don't do what I've asked them to quote for etc.

I'm still getting quotes, as I'd prefer an installed system, but that depends on how much the quotes come in at. One of the quotes I'm waiting on by Convert Energy seems very thorough, but he's said there is a mandatory 300mm setback between the panels and the limits of the building envelope. So rather than south facing he's going to quote on east/west, which means the panels can be fitted closer together, and thus use larger panels. So the actual estimated annual energy is actually slightly more than south facing with smaller panels 330 v 405w, the 405w would produce more south facing but won't allow for the 300mm around the outside. These are the mounts I found, but couldn't find any prices online, they do different ones for different roof materials and cold roof/warm roof etc.. https://www.nicholsonsts.com/products/rooftrak https://source.thenbs.com/category/uniclass/roof-anchors-for-solar-modules/wyCiF7pKPZkGMc1XvA1ejY/search-results/products?f=Category&v_1=Roof anchors for solar modules&score=0 Technically I'd argue that by definition a flat roof does not have a ridge line, I think you need to be within 200mm height to count as permitted development, put a parapet along the side that won't cause shading, and suddenly you have more height. If you put the panels at too shallow of an angle they won't self clean, and dirt and debris will build up, unfortunately I've no idea what that angle is.

I'm currently trying to clarify whether or not planning permission is required for a flat garage roof. Have emailed the council, but no reply yet. I think as long as they are not meet 200mm height on top of the roof then this is permitted development, but that would require the panels to be almost flat, which is not good. You can now get through roof mounts, I don't have the link handy as I'm at work, they have a plate that screws to the existing structure, then a large piece of roofing membrane that's bonded to the mount, then once screwed down is then sealed the same way as your existing roof. This is what I'm looking to use, as I don't want loads of weight on our garage roof, the beams are not up to it. Many roofing manufacturers now accept the above mounts, and they won't invalidate their roof guarantees.

I had a reply from the DNO today, much more useful information this time. I'm pretty sure I'm going to need an AC connected battery, so the battery can be charged from both arrays, so what dos the fourth paragraph mean, installation wise? Is that fairly straightforward to achieve, or very expensive?

I spoke to the DNO today, the guy I spoke to suggested I put it in an email, when I said I already had, and the reply was just to submit a G99, he said to resend it and add that I'd spoken to him, so we'll see what comes back.

@Nickfromwales Do you have a link to a build thread of what you are intending on installing? Our gas bill isn't too bad, between February 2021 and February 2022 what we used at current prices equates to £600 of gas + £100 standing charge. Just had a quick look at costs of cylinders and they are not bad, its something to consider as I could install myself back where the original hot water tank was. One consideration is that if installing a battery of sufficient capacity then there would be a lot less spare solar energy to heat the water though.

Those Storedge batteries are rather expensive, Midsummer have the 10kWh battery for £5850, which is almost double the price of the GivEnergy 9.5kWh battery 😲 I was reading the Storedge instructions, this safety warning got me "Do not place any combustible items within less than 2.5 m / 8 ft of the Battery" hmmmm, server room is also a cloakroom, so full of coats, garage is full of all sorts of combustible stuff, just how many are installed, or remain in a 2.5m clear area 🤔 At least it actually has a built in fire extinguisher.

Already tried that with an informal email to sound things out, I got a reply back saying not something they could answer and I would need to make a G99 application. Would a phone call likely get me any more info? DNO is UK Power Networks. Edit: If they don't approve the full amount, do they tell you what they would approve? My understanding is a DC battery would only charge from the array it is connected to, and the excess power from the existing array would still get exported, is my understanding correct?

Thanks, I was reading it as multiple units on a single phase, rather than multiple single phases.

What does this bit mean on the G99 form, its just above the signature box?

Yes it is, thank you. For this box ticking exercise I'm listing a Solar Edge SE5000H, which lists a power factor of 1, but adjustable -0.9 to 0.9, so I'll just enter 1 Now just to work out a inverter/charger to put some specs on the sheet - I'll aim for one with a 5kw capacity. Just took a look at what Solarwatt have to offer, and I really like the look of the Solarwatt Flex AC-1 battery, it wouldn't look out of place in our hallway (Mrs Ronksi will disagree though!) or it would even fit in the server room. Only downside (ignoring price which I cant find - anyone know the price?) is it looks like it has quite a low power output/charge rate, and to get the best you need many packs, but even the base system would have enough output to cover our base load and a little bit more, and should be OK charging off peak in the winter months. I'll list a Victron Multiplus-II 48/3000/35-32 as that has a peak power of 5500W JA Solar do a 545w panel, but its 1134 x 2279, and £192 each excluding VAT, but all depends on what fits better and kWh and price per square meter.