3 orientations headache

KungPao

Hi all,

New to all this and in the Googling every little thing phase…

So, my roof is a bit odd. I can only fit 4 panels on east and 4 panels on west, not so bad, but I can also fit 2 on the south part. However, I heard that's not going to work, as those 2 panels won't generate enough for the inverter.

Am I stuck with a setup where my southern roof cooks at midday but has no panels to make use of it, or can some magic be done with micro inverters for those 2 panels? Or in reality would the load be fine at midday as the east and west panels would generate enough to make up lost power from the 2 south panels. Or do I suck it up and just go with east and west?

Angle of roof is about 28 degrees.

This is my roof and ideal setup of 10 panels. Any advice appreciated!

con747

https://www.boards.ie/discussion/2058425454/3-orientations-headache

I'm not sure if paralleling the south and east or west on one MPPT might work because of the 2 panels but others would know for sure.

DC999

My roof is the same. Based on the hassle I had, go with E and W and ignore the tiny S. Inverters take 2 strings on different orientations and you have 3 - so that is problem #1.

You are correct that S won't start up with only 2 panels. I've 3 and it misbehaves a lot as the startup voltage isn't reached. Installed are unlikely to want to add micro inverters. But ask by all means.

See can you get more E or W panels on an extension - I use two roofs on my E string. Then you aren't limited to 8 panels. I've 20.

In time you can DIY panels on your shed with micro inverters. I did that twice.

KungPao

Thanks for the help.

@dc999 is your roof a steeper pitch than mine at 28ish degrees? If I could use micro inverters on 2 south panels - I think it may be okay for me as at midday my east and west panels will be in good sun too, I can see right now actually, my east and west sides are totally in the sun (and south obviously) - not bad for nearly October, then a bit later west and south will equal sun, then west only later of course. So 8 on main inverter, 2 on micros, maybe it's still bad overall for performance?

So right now I could be collecting from 10 panels, then 6, then 4 in the early evening…

Half thinking another option would be to have 2 panels on the south, on micro inverters and only connected to an Eddi, get some use of that aspect at least, and the hot water would be very welcome over May to October when the central heating isn't on much. Cheaper than thermal solar I guess…

keno-daytrader

Do you have a garage? I have 10 on my house and 10 on my south garage.

KungPao

https://www.boards.ie/discussion/comment/123852104#Comment_123852104

Sadly not, only options are the roof of the house. No shed either and garden doesn't suit for ground mounts. So it's either 8 for a basic east/west system, or 10 with some luck.

keno-daytrader

Some solar guys are really good with coming up with solutions, others only want to install a bog standard x panel system and get on to the next one. Id ask for 4kWp inverter and 2 microinverters for the 2 south and see what prices you can get. The FB group with 72k Irish members are really good for inquires like yours.

KungPao

https://www.boards.ie/discussion/comment/123852142#Comment_123852142

Thanks for that. I've just had one company give a good quote but like you say, it's east/west only and on one 3.6kw inverter and job done, and they say it's not enough power to have a battery…bummer.

I'll have a look at that group for sure.

I want to get this done properly and make the best use of it, I'd hate looking up at a bare part of my roof…facing south like…

Zardaz

Suggestion 1:

Put the 4 W panels on one string. (they dont appear to be shaded)

Put the 4E AND the 2S together on the other string. But you will need optimisiers on all those 6. (will probably cost €200 - €400 extra)

suggestion 2:

Look into using smaller panels. You might be able to fit more of those and cover more roof area, getting more KWp overall.

Suggestion 3:

Get better measurements. Can you fit panels in 2 landscape rows instead of one portrait? Would need a roof 'height' of 1134mm*2+500+200, or about 3 meters. (that's about 10 rows of 30cm tiles)

Suggestion 4:

Use the N roof for more panels. But they will only be 50% as good as the S ones, will need to share a string, and will need optimisers.

Suggestion 5:

Do try and get the battery. Even if you don't have enough power comming off the roof to put much into it, you could charge it for cheap overnight. You will need a hybrid inverter for that. (a few 100 more expensive, but the battery will be ~1K+ anyhow for 5KWh)

conor_mc

I have 3x orientations, and I used optimisers to put 2 orientations on one string. I also had some potential shading from a chimney so it made the decision on which orientations to pair up easy, ie one with potential shading plus one potentially below start-up voltage. In your case, S+E I think.

ECO_Mental

Have you got a 48V battery? if you do why dont you just get a solar charge controller https://www.victronenergy.com/solar-charge-controllers and put that on one string. Job done…this will charge the battery and it wont affect your NC6 either as its not grid connected. Simple easy solution if you have a battery that is

MakersMark

Is Pv hot water an option on your south section.

Hot water is a very large part of energy consumption.