Is north facing solar a complete waste

unkel · 31-10-2022 12:08am

@DC999 - I have most of the panels ready for a north facing string. Still need inverter and mounting materials but will post in here once done.

SD_DRACULA · 31-10-2022 12:26am

https://www.boards.ie/discussion/comment/119814005#Comment_119814005

Interested in those extra 12 kwh in December? 😂

unkel · 31-10-2022 12:54am

https://www.boards.ie/discussion/comment/119814062#Comment_119814062

My north facing string will have a pay back period of about 2 years 😁

Doesn't really matter when it goes up but as always, I'd like it done by yesterday.

Manion · 31-10-2022 8:35am

Another month to go before the installation. I've ordered myself a few Shelly EM devices so regardless of what monitoring the inverter comes with I'll have full stats from the start.

Fantana2 · 31-10-2022 10:11am

https://www.boards.ie/discussion/comment/119814126#Comment_119814126

Could you break down the ROI calculation?

Manion · 31-10-2022 10:47am

From the RoI thread

One thing the sheet allowed me to easily do was to play around with what the difference is between North, South, East and West Solar in a very easy way. I had started the thread: Is north facing solar a complete waste a while back and it reaffirmed what I'd worked out manually. For large systems at the right price point the the difference between North facing and East or West facing is only a 1 year on the RoI. Going from a 6Kw Solar with 4Kw battery system to an 8Kw Solar with a 8Kw battery system made no significant difference on RoI North facing (Still ~8 years) but for a East facing system the RoI went from 5.8 years to 6.7, added on nearly a year to the RoI. The big difference is that with you get a better spread of Solar generation from may right up to August with nearly 100% of daytime solar demands met, whereas with North facing the generation is much more tightly centered around July. North facing generating 21.7% less solar power annually than east and 33.9% less than South.

Given that the Installation cost is actually cheaper than the quotes I was getting in December and January this year for a bigger system (came up ~ at the guidance), and electricity has gone up nearly 50%, it seems like a sound decision.

Gerry · 31-10-2022 2:50pm

have 4 NE panels which came with the house. Their output has really fallen off a cliff since September. I imagine the inverter will be rarely firing up by end of november.

unkel · 31-10-2022 3:11pm

The inverter "fires up" as soon as you produce as little as 10W or so, so yes it is even working on the worst day of the year. Obviously a lot less though. To give you a comparison, I make near 100kWh on the best day of the year and about 1kWh on the worst day of the year

Gerry · 31-10-2022 5:45pm

Sure, if you have enough panels. 1kwp panels of these NE, make 2kwh midsummer.

whats my point . I can see the point of North facing as an addition in the summer, but as the only aspect, it would be extremely frustrating.

Manion · 31-10-2022 8:25pm

I'm not sure I'll be frustrated as I'll have done the best I can. Mainly keeping an eye on the average cost per unit. I can see the frustration from having bought a property with solar that is just on the wrong side of useful.

slave1 · 31-10-2022 8:29pm

I have NorthEast facing panels on the rear of the house roof, expect them to be frosted over and not defrosted due to low sun at the depths of Dec and Jan for days on end with zero generation, great in the Summer though

Manion · 29-11-2022 11:46am

IMG-20221129-WA0001.jpg

IMG-20221129-WA0000.jpg

Finally happening. I didn't really believe they would get all 20 up there but now I see I could have got 21.

DC999 · 29-11-2022 12:16pm

https://www.boards.ie/discussion/comment/119934504#Comment_119934504

C

L

A

S

You're finally there. I'm very interested in the numbers out of curiosity. More solar we can plaster everywhere, the better.

SD_DRACULA · 29-11-2022 12:33pm

What size W are those panels, they look tiny

Manion · 29-11-2022 1:41pm

No, they're just far away 😉. They're 405 watt Longi hiMo panels. 2 meters by 1 meter.

graememk · 29-11-2022 1:59pm

https://www.boards.ie/discussion/comment/119934690#Comment_119934690

😂 Had to.

Galego · 29-11-2022 3:38pm

https://www.boards.ie/discussion/comment/119934504#Comment_119934504

What's in between 8,9,10 and 15,16, 17? Roof vents? Pity about those if so. It could've been an extra 3 panels.

Anyway, class job. Very interested in seeing how well it does. Keep us posted! :-)

SD_DRACULA · 29-11-2022 3:54pm

Lol I am looking at the windows below and they are about the same as my house, and the roof, height-wise about 6m looks fine but no way the width of the roof is 10m?

Manion · 29-11-2022 5:29pm

Sorry yeah I've been thinking in terms of rough size, the panels are: 1722 x 1134 x 30mm so Approximately 9 meters. Which is actually a bit more than I had on the plans, but shrug.

It's shaped like that due to vents. Another installed kiboshed the entire thing at the start of the year due to the vents but all that was needed was a bit of tetris. They're not allowed to cover the vents even if there would have been plenty of clearance for grant reasons.

I think I'm at the max with 20 panels, I'll have to check but I recall either the maximum per string or overall Max. I definitely could have got one more in. I think it looks great tbh, really stands out but not in a garish way.

SD_DRACULA · 29-11-2022 5:39pm

I'd put 4 more there after the grant, and split the strings 12/12

slave1 · 29-11-2022 8:55pm

Doubtful you'll get 12 410w panels on a string due to voltage capacity inverter side. I was maxed at 8 455w panels on my 6kW inverter

unkel · 29-11-2022 9:01pm

Depends on the spec sheet of the inverter and the spec sheet of the panel, but could well be perfectly fine in most cases.

Manion · 29-11-2022 11:56pm

What would one be looking for on the spec sheet. I see max voltage as 600 volts on the inverter dc input spec. Readings indicate 350 volts.

slave1 · 30-11-2022 12:18am

It’s the voltage rating of your panels, they are on your panels spec sheet

Manion · 01-12-2022 11:30pm

OK the inverter can support Max. Input voltage of 600v. Max output per panel is 31volts. I've 2 strings, so in theory should easily get 12 on each. Interesting.

So only two days so far but so far so good. Total I saw 3.5kWh yield. The average I'd budgeted around for December was 2kWh per day but I'll not count my chickens yet so to speak.

Solis hybrid datasheet.pdf

20220323-longi-data-sheet-lr5-54hph-400-420m-dg-version-v04-lowres-en.pdf

graememk · 01-12-2022 11:38pm

https://www.boards.ie/discussion/comment/119946798#Comment_119946798

Max voltage of the panels (VOC) is 37ish

31v is the working voltage.

But 12 on each string is possible, (even when cold etc)

slave1 · 02-12-2022 11:39am

Yeah, it's VOC, I was surprised I could only get 16 panels on my 600v inverter but they are 455w and big bois

bullit_dodger · 02-12-2022 12:58pm

https://www.boards.ie/discussion/comment/119947868#Comment_119947868

It's per string though mate - least I'd be pretty sure of that. So most people can get 12 panels (13 if you really push it and have a panel that has a lower Voc voltage) on each string, giving you 24 panels in total. There are of course some power (kw) considerations to also keep an eye on, but most 6Kw inverters can do 24 panels.

Galego · 02-12-2022 2:52pm

@Manion

Be nice to see what your panels produced today, relatively nice day in Dublin.

My 4kwp produced 3.7kwh yesterday and today 6.3 so far. I'd be interested to see if you do the half of my number to see if north this time of the year produces around 50% of south.

Manion · 02-12-2022 7:24pm

Alas only 2.9kWh generated today.

Galego · 02-12-2022 8:04pm

https://www.boards.ie/discussion/comment/119950106#Comment_119950106

That's not too bad. I am starting to think that it's impossible to compare productions for different systems as location (even within few Kms) plus other variables seem to make massive differences. One day your system may do better than mine and the day after could be the opposite.

A learning curve here for me.

DC999 · 02-12-2022 8:52pm

https://www.boards.ie/discussion/comment/119950106#Comment_119950106

Don't sweat it. You're live at the lowest production of the year. I got under 5kWh on a 5kWp system and we had decent sun at times today. I was spooked when mine went live at first and was the weather. And I was spooked looking at stats from people with similar systems who got better output. But some months mine outperforms them. As @Galego says, no rhyme or reason on a daily or weekly basis. Only get the picture when look at a longer time frame.

To compare 'not apples and apples', but to give you some comfort of output at this time of year, here's my downward staircase of output. Only live since late July so ignore that month. Aug was huge compared to prior years re others, Sept nearly half of that, Oct dropping but not hugely, Nov nearly half of Oct (or a quarter of Aug!!), god knows what Dec will bring :)

Looking at stats from others, it will start to climb again in Jan (slowly) and ramp from March.

For those of a certain vintage, as Yazz once said many moons ago, the only way is up, baby! Well, post the solstice :)

I still think you're brill for trying it. I re-read the thread the other day and it started in Jan this year with 'is this idea nuts, or not'. And then flip-flopped a few times. We need that bravery at the moment.

Solar yield by month 2022 (live end July).png

SD_DRACULA · 02-12-2022 10:58pm

I want to see daily/monthly stats for these panels, might be my next project 😉

Manion · 03-12-2022 1:21am

Ah yeah, I'm really very happy. The thing about north being roughly half the output of south is taken over a full year. On any given day it could be way better less than half or way more.

The comparison to south orientation is interesting but ultimately miss leading. The real benchmark is again the cost of importing power and the average cost per unit.

The batteries aren't working properly yet, the installer needs to call back. I think once that's sorted I've be at zero export and 8pm before pulling from grid most days. That would be my advice to anyone looking into this, pick a goal and work backwards to what you need. 90% self consumption and off grid till after dinner where my goals.

unkel · 03-12-2022 1:34am

That's exactly it, @Manion. Pick an ambitious goal and work towards it. My goal is to no longer use any fossil fuels at all and also to produce more energy than I use.

Fingleberries · 06-12-2022 5:05pm

Just want to say thanks to everyone for contributing to this thread. It's a very interesting read because the south facing side of my house (mid-terrace North county Dublin) has a dormer window that takes up valuable space for Solar panel - I think It would probably fit about 6 or 8 panels, if I eyeball it and if panels can be installed with vertical or horizontal orientation.

The north facing roof would be similar to Manion's, and I'm monitoring this thread to see if it would be worth putting many panels on it (with the understanding that Winter will have minimal production, and even in Summer it'll be much less than south facing).

Snugbugrug28 · 08-12-2022 2:30am

Sorry to be the guy that didn't trawl back through the thread but what was the final cost here?

Manion · 09-12-2022 11:48am

Hi,

Final cost was 16K before grant:

* 8.2 kWp - 20 410 Longi panels - LR5-53HPB-410M

* 10.6 kW - Waco 5k3 Batteries - DC Connected

* 6 kWh - Solis Invertor - Solis-RH1-6K048ES-5G

Cost comes basically at or slightly below the guidance.

Snugbugrug28 · 12-12-2022 8:54pm

https://www.boards.ie/discussion/comment/119974347#Comment_119974347

I'd love to do it myself but I'm in a new build A2 rated house (east/west) and my last 2 month bill was 200e. I don't think I'd qualify for a grant and the payback time would be just too long

DC999 · 12-12-2022 9:11pm

https://www.boards.ie/discussion/comment/119988852#Comment_119988852

You mean the payback would be too long if you didn’t qualify for the grant? Why no grant available? Re Solar Electricity PV Grants | Home Energy Grants | SEAI ‘All homeowners, including landlords, whose homes were built and occupied before 2021 can apply.’ Maybe you moved in after that date.

I’ve an E/W and it produces a solid amount. If you get an EV it will use maybe 3000kWh a year for ~15000kms – crude benchmark.

FIT pays up to 22c a kWh now. So helps reduce the payback time.

Snugbugrug28 · 12-12-2022 9:24pm

https://www.boards.ie/discussion/comment/119988911#Comment_119988911

Yes I just occupied from July this year unfortunately. No EV and don't drive enough to justify one (yet).

Must read up on the FIT

Mr Q · 13-12-2022 1:20pm

https://www.boards.ie/discussion/comment/119988852#Comment_119988852

I didn't qualify for the grant and installed an E/W system for much less than what people are paying on the quotes thread after the grant.

Don't rule it out even if you can't get the grant. If you can DIY any of it or have family/friends that could help, you will come in at a lower cost than what people using installers and getting the grant are.

unkel · 13-12-2022 3:36pm

Much cheaper. Good point @Mr Q. I have bought parts quite cheaply over the years and regularly see quotes mentioned that are ballpark on the guidelines and are after grant twice as much of what I spent, for half the size of the system that I have. And I haven't even done everything DIY, I did have a roofer out one day and I have paid for an electrician once too.

Snugbugrug28 · 13-12-2022 9:36pm

I wouldn't have a clue how to DIY such a thing, do you guys know of any guidance for it?

unkel · 13-12-2022 10:45pm

https://www.boards.ie/discussion/comment/119993453#Comment_119993453

Yep guidance is youtube. But you will probably end watching hundreds of hours of stuff. Or more. Don't ask me how I know 😁

Start with the usual suspects like offgrid garage

https://www.youtube.com/%40OffGridGarageAustralia

and Will Prowse

https://www.youtube.com/%40WillProwse

graememk · 13-12-2022 11:36pm

https://www.boards.ie/discussion/comment/119993774#Comment_119993774

another one ive recently stumbled across is Projects with Every day dave

https://www.youtube.com/@ProjectsWithDave

He has some start to finish guides, (although in the US but a lot still apply) Seems to love optimisers though!

Fingleberries · 05-01-2023 2:13pm

https://www.boards.ie/discussion/comment/119951496#Comment_119951496

@Manion - I'm hoping to learn as much a I can from your experience for my own potential install. The south facing roof on my mid-terrace house has a dormer window sitting in the middle of it (I reckon I could probably squeeze 4, or maybe 5, panels on it). But the North facing roof has much more room (excluding a velux window), and I could probably fit 5-8 panels on that.

Going by the vague rule of thumb that a north-facing install would produce maybe 50% of a south facing install (using https://re.jrc.ec.europa.eu/pvg_tools/en/ appears to bear that out for the most part). I'm shopping around and weighing up my options - but your install is giving me hope, as I thought north-facing was a complete no-no in Ireland.

How have you found it since the install was completed? What sort of results did you see for December? (also, is your install solely north-facing, or do you have a separate install on south-facing also?

Manion · 05-01-2023 8:19pm

Hey,

Some stats from the Inverter.

Monthly Yield(kWh) 61.000
Total Yield(kWh) 74.000
Monthly Energy to Grid(kWh) 3.710
Monthly Energy to Battery(kWh) 119.000
Monthly Energy from Battery(kWh) 159.000
Monthly Consumption Energy(kWh) 398.000
This Month Full Load Hours(h) 7.440

I didn't have all my stats set up until Christmas week so not pretty graphs and also I had an issue with the battery that wasn't resolved until the same week so stats there are down. The model predicted that I would hit 75 kWh for the the month of December but I only hit 61. For most days of the month I was getting about 20% above the predicted daily yield but then the ice came and kinda ruined that trend.

The entire roof is Northfacing. So far I'm pretty happy with it, I'm thinking of ways I can tweak the meter CT clamp so I eliminate all exports. The thing to keep in mind is at the moment I'm not getting half a south facing install, I'm getting about 25%-30% of one and during the summer months I'll get about 60% of one. The generation is much more focused around the summer months. The biggest consumer of energy in our house is sockets, which isn't seasonal. Followed by the heatpump and the hot water heating. So there are a lot of specifics to this which make it a good idea. Furthermore we've a massive roof, 62 square meters, 20 panels, absolutely no shading from nearby buildings or obstructions.

You generally have the option of two strings for your solar installation, if I was you I'd install as much as possible south facing, even 4 panels and max out what you can install north facing. Think of the north facing panels as augmenting and south facing installation. It wasn't that uncommon a few years ago for people to have 2kWh installations. Putting 6kWh of capacity on the north facing roof then just becomes a matter of the marginal costs. All of this really just comes down to the cost of installation.

unkel · 05-01-2023 9:41pm

Good point about the much lower marginal install / labour costs of installing lots of panels on a N facing roof.

Fingleberries · 06-01-2023 12:40pm

https://www.boards.ie/discussion/comment/120068782#Comment_120068782

Quick update: The first company I called out for a quote was a complete bust. They came out to the house and didn't even go in, they said they could probably only fit 1.6kWp on South and they wouldn't install anything on North-facing (because, and I quote, "The SEAI won't give the grant for North Facing" - which I believe is pure waffle). Their loss, I'll move on to other companies for quotes and the like, I'll update here as I go along.

Is north facing solar a complete waste

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