Is additional North facing Solar Panels worth thinking about?

okmqaz42

TLDR:

Getting south facing solar panels - should I also get some north facing ones - did you and what was the result?

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I am pretty far along figuring out what I want.

I have a plan for 10 south (tiny bit SE) facing panels, Hybrid inverter to allow consideration for battery in the future and the ability to DIY a water diverter in the future.

But what I am wondering is has anybody added additional panels to the north facing roof and what results they have seen.

My logic is that it in the scheme of the over all project adding 4 panels to the north side is not a massive cost and during the summer/shoulder months will see some gains based on my maths/angles and historic sun hours.

I would be doing this mostly for carbon off-setting and hoping when the FIT comes in that my summer credits would help with winter bills.

Thoughts?

Panels are very cheap. If you have the space, go for it.

I can see myself filling my NE roof side at some stage in the future.

slave1

Forget about FIT.

I have NE facing panels, useless in Winter, frosted over 24/7 a lot but in the good months great for early morning sun and dribbles during the late afternoon evening.

But the question is would you make use of them at that hour or would you be producing excess after (future) battery top-up ?

BTW if you are looking at future battery setup then do it at install to maximize grants, to buy a hybrid inverter (twice cost of non-hybrid) for something you MAY do in the future is a waste of money.

I know you didn't word it directly but just in case, you don't need a hybrid inverter for a hot water diverter.

graememk

If your not going for a grant, go for a straight inverter, as slave1 says hybrids are twice the price.

And if you are going for a grant, get the battery as I don't think just having the hybrid qualifies for the full 3k grant.

If you go down the line of a battery then it might just be easier to have a storage inverter instead, not touch your installed system. ( Or swap out for a hybrid then and sell the normal inverter,)

okmqaz42

Thanks for the feedback guys. I had dismissed the battery from reading all the comments here but since i seem willing to just add extra panels to the north face the batteries might make sense regardless of the payback it still makes more sense than just sending it to the grid FOC?

https://www.boards.ie/discussion/comment/117739083#Comment_117739083

One battery is more or less free when you factor in the grant. There was peanuts in the difference for me if I went for battery or no battery. No brainer to go for one imo. Get quotes with and without a battery.

SD_DRACULA

I don't think it makes sense going by the numbers.

That's for 2kws of panels North facing, and you get about 900 kwh extra per year (most of it in the months where you have loads of generation from South panels). If you need to optimize all the panels it makes even less financial sense.

That's at my address in Dublin, but I wouldn't say it's crazy different across Ireland, work it out yourself https://globalsolaratlas.info/

okmqaz42

https://www.boards.ie/discussion/comment/117771620#Comment_117771620

Thanks for that link. It’s more or less the conclusion I’d reached. Was not so much about the cash cost but doing something so pointless does not make sense

SD_DRACULA

Having said that I don't have much else that I can do panel wise with my current setup, so who knows might do it next year just for the hell of it.

When the sun is high it might make enough to keep the battery topped up until later in the evening (when I waste the most) but I wonder if it will have a negative impact on the south facing panels since they would be on the same string 🤨

okmqaz42

https://www.boards.ie/discussion/comment/117773302#Comment_117773302

I think the optimisers or mini inverters work out the shading issue - based on my limited reading anyway. I’m not doing a battery yet so I think for me I’m firmly kicking this one down the road but do appreciate the comments

slave1

https://www.boards.ie/discussion/comment/117773302#Comment_117773302

All of my 8 NE facing string can be frosted/frozen over in Winter so I think yes, they could impact other panels if all on the same string

reklamos

I am in the same boat. Have North facing roof that could take 2-3kw of panels. I had some testing done and as most mentioned, in winter there is no use of them but summer evenings would add good amount or would keep the battery topped up. I have inverter with 2 strings and only one is being used. I was thinking to add them earlier next year if I can source them cheap and get someone to mount them.

https://www.boards.ie/discussion/comment/117771620#Comment_117771620

With the way climate change is going.... that can be used to offset the future air con install

SD_DRACULA

I'd say it's worth it if you don't need optimizers and can mount them yourself otherwise they might not pay for themselves

Maxxx17

The panels are very cheap. If you have the space you can try it. I can see myself filling in my northeast side of the roof at some point in the future. 

SD_DRACULA

Can someone with some N facing panels put their generation here for a year/per month? Curious to see real life values not estimates.

unkel

The estimates are pretty accurate. Basically a N facing panel at a typical angle roof in the Dublin area (or any other of the better solar PV areas in Ireland) produces about 50% per year compared with a S facing panel. The higher the angle of the roof, the smaller this percentage. Does that not give you enough to work with?

I have an empty north facing roof and if I didn't have almost 8kW of panels, all south facing, already, I'd plaster that roof too. Maybe some day I will if restrictions on max output are relaxed and we get a decent FIT.

SD_DRACULA

Well predictions for Ireland are at best optimistic, i.e. this August was predicted 700kws but only 500kws so far so it's good to see real life to compare.

I know many factors can affect it, it's not like someone has them next door to me to get an 100% picture.

SD_DRACULA

Was speaking to the midsummer guys and they said it's not a good idea to mix N and S on the same string because even with optimizers the N panels can bring down the S ones so if that's the case then N needs its own string, shame the Solis only has 2.

graememk

https://www.boards.ie/discussion/comment/117805652#Comment_117805652

August might be the only month that I wouldn't beat the prediction.

The first 3 weeks were gloomy at best!

On average it's accurate enough

slave1

https://www.boards.ie/discussion/comment/117804994#Comment_117804994

LOL, restrictions, that's hardly stopping you now

unkel

https://www.boards.ie/discussion/comment/117807085#Comment_117807085

It is. If I get checked for FIT and my system would not be compliant, I won't get it. Don't want to risk that.

unkel

https://www.boards.ie/discussion/comment/117805652#Comment_117805652

LOL, I didn't think you meant predictions for the next day, week or month 😂

Estimations for the year are pretty accurate, but of course these are averages and vary year on year

unkel

https://www.boards.ie/discussion/comment/117806600#Comment_117806600

There are 3 MPPT input string inverters. Or you could have a separate system with its own inverter for your N facing panels. Or of course an off grid system. Might come in handy for all those blackouts we hear about in the media that are coming to us from this winter...

SD_DRACULA

https://www.boards.ie/discussion/comment/117808323#Comment_117808323

I am technically at the 1 phase limit with my current 6kw inverter so if I were doing this right, I'd need a 3 phase supply, change the solis to a 3P hybrid 10kw and then I could put 3kws N on its own string and bring everything to 10kw 🤤

Going to put in that ESB NC form for 3 phase today, they said it costs nothing for the assessment so why not.

KCross

https://www.boards.ie/discussion/comment/117809578#Comment_117809578

You do realise that requires more than just work on the ESB side? You'll need to get rewiring done inside the house as well which wont be in the ESB quote! If its all just to get a few extra kWp on your roof, 3ph will never pay for itself.

unkel

Much easier to stay 1ph and just limit your max export to 6kW?

SD_DRACULA

https://www.boards.ie/discussion/comment/117809778#Comment_117809778

For sure, I doubt I will go for it just for that but curious about the price and some futureproofing since 3p can charge EVs faster also.

https://www.boards.ie/discussion/comment/117809799#Comment_117809799

Yeah that's exactly what I would do

unkel

Charging my car at home at 23kW would be nice alright 😁

Eva777

Hi all, I woud be grateful for some advice: Using a compas app on my phone, I figured out that my roof is exactly 45 degrees North East facing. There is room for a maximum of 8 panels. As the Irish sky is mostly cloudy and overcast, I'm wondering if it worth my while to get a solar system with this type of roof?

con747

https://www.boards.ie/discussion/comment/120180039#Comment_120180039

Have a look here https://play.google.com/store/apps/details?id=jp.gr.java_conf.siranet.sunshine&hl=en_IE&gl=US

and here https://re.jrc.ec.europa.eu/pvg_tools/en/tools.html It will give you an idea of what you can generate and where the sun will be during the year on your roof.