Solar panels and battery - any real world reccomendations?

Alright I need the brain trust here!

Install started today but it's clear that the layout the installers picked won't work, they had three panels stacked horizontally on the left/upper roof, and that is no bueno.

I have come up with two core designs that seem to work:

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Design 1 on the left fits all 12 panels on the roof, but it's a little messy because I have to mix and match portrait and landscape modes.

Design 2 on the right drops 2 panels down to 10, but it's got a bit more breathing room.

Dimensions are shown above, including those for a panel in case anyone has any good ideas I've missed? 30mm clearance on the very edges for safety/wind loading/space to install bird mesh, which is the section in pink/red.

Which do you prefer? Bearing in mind that Design 2 loses 740W of panel generation (4.44kwp => 3.70kwp) which means I may as well have just gone 3.6kwh inverter and no DNO route, would have been cheaper and quicker.

In theory it's possible to add 6 panels horizontally to Design 2 but I'd have to move them up a little. Design 1 could also have a 13th panel added vertically but it would lose that sense of balance doing so.

Roof is to the rear of the house, I won't really see it myself unless I'm at the very back of the garden. I do however not want to put up something that is too ugly.
 
Design 1, and shouldn't the 30mm be 300mm, presumably a typo

I actually have one roof with 6 in portrait, and two in landscape.
 
I can in theory add a 13th panel to Design 1 I think.

I think it sort of looks like it will work well to add it in? that roof is a bit longer than the other one.

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Ron-ski said:
Design 1, and shouldn't the 30mm be 300mm, presumably a typo

I actually have one roof with 6 in portrait, and two in landscape.
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Yes, I made a typo, it's 300mm :)

The top/bottom clearance combined is only about 80mm though, They said the side was more important and not going above the ridge at the top.
 
HungryHippos said:
Lucky 13 it is!

Installer said extra £300 basically and the panel is a done deal :)
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Yes get as many panels up as you can, as they help in the winter. I managed to squeeze 4 more in. Only paid for the two tho (£375 for the both of them) as a compromise for not having the jinko 400w panels available. I ended up with some TW solar 390w instead. Panels should be seen as replaceable anyway imo. Who knows what the panels will look like in 5-10 years time? If they are 600w as standard, and a similar size. It might be worth getting them replaced, an easy job if the rails, clamps and wiring is in place etc.
 
casper_uk said:
Yes get as many panels up as you can, as they help in the winter. I managed to squeeze 4 more in. Only paid for the two tho (£375 for the both of them) as a compromise for not having the jinko 400w panels available. I ended up with some TW solar 390w instead. Panels should be seen as replaceable anyway imo. Who knows what the panels will look like in 5-10 years time? If they are 600w as standard, and a similar size. It might be worth getting them replaced, an easy job if the rails, clamps and wiring is in place etc.
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Yep, should be a good system, overall price is fairly keen still, even with the uplift of £300 for the new panel (I don't think £300 sounds like a great deal, but it's not that bad on top of what I was paying I think).
 
To confirm something I read earlier in the thread; if I get solar and battery, I'm still connected to the grid. Do I have access to solar and battery power during grid faults? Or is it shut off to protect workers?
 
You could do both but usually the kill switch isn't included and is extra cost with not many suppliers offering it as it involves yet more approvals.
 
DampCat said:
To confirm something I read earlier in the thread; if I get solar and battery, I'm still connected to the grid. Do I have access to solar and battery power during grid faults? Or is it shut off to protect workers?
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I was quoted an extra £700 to have the necessary switch installed
 
This is a diagram of what our ten panel will look like on the roof. The four panels on the right in blue are shaded till about 9.30am by the neighbours house. The sun moves right to left so panels 4 and 9 will clear first and then 5 and 10. The orange line shows shading from the chimney in the early evening (6.30pm at the moment). Note we will be installing Tigo optimisers on all panels.

So how best to wire them? The inverter we're getting is a Givenergy 3.6 Gen2. This has a start up voltage of 150v and an MPPT range also starting at 150v. The solar panels have a voltage at maximum output of 38.6v. I think there are the following options:

1 - Put panels 4, 5, 9 and 10 on one MPPT and the other six on another MPPT. This means that six of the panels can start generating quickly and the other four (4, 5, 9 and 10) will come on stream when they are all clear of shade. BUT - 4 x 38.6v = 154.4v. This is only JUST in the usable range for the inverter - it feels a bit too tight for me.

2 - Put two equal rows of five on each MPPT - so 1, 2, 3, 4, and 5 on one MPPT and 6, 7, 8 , 9 and 10 on the other MPPT. But this means that although 1, 2, 3, 6, 7 and 8 have enough voltage to start the inverter, there isn't enough for each MPPT and won't be until the remaining panels are clear of shade. This looks like the worst option to me.

3 - As per option 1 - put 4, 5, 9 and 10 on one MPPT and also add panel 3 and put the others on the other MPPT. This at least means that five (1, 2, 6, 7 and 8) will start generating quickly and there will be a comfortable voltage on both MPPTs (5x38.6 = 193v). This configuration might also help later in the day given the way the shade from the chimney falls as 3, 4, 5, 9 and 10 are the least affected.

4 - Put all ten on one MPPT. Without Tigos this would be a non-starter but even with Tigos, still not sure it' the way to go.

The main issue here is the high startup voltage of the GivEnergy inverter. I know there are other inverters with a significantly lower voltage requirements but difficult finding an installer to who you can say "I want THIS inverter, THIS battery, THESE panels" :)

Any advice greatly welcome ahead of a site visit from installer.
(Apologies if some members might have seen this also on a different discussion board).

free cdn image hosting


 
upnorth said:
Any advice greatly welcome ahead of a site visit from installer.
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As you pointed out you have shading from different parts, so optimisers are the obvious choice. I would be looking at 3, 4 ,5 ,9 ,10 in one string with the remaining panels in the second string. Startup voltage and current should not be an issue then, and you'd be doing the best you could. How often is panel 3 shaded, or not at all, e.g. would there be full sun on it before that of 4, 5, 9 and 10?

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On a separate topic, can see this thread getting busier from today, now that figures have landed for the new price cap on both gas and electricity. Just in time to get quoted huge sums of money for a system then might have got 50% cheaper only 9 months ago, therefore making the payback time as long as before they might have considered installing it on a cost/price basis. I don't know whether that is sad or good, as we'll be generating more renewables as the bonus.
 
Journey said:
As you pointed out you have shading from different parts, so optimisers are the obvious choice. I would be looking at 3, 4 ,5 ,9 ,10 in one string with the remaining panels in the second string. Startup voltage and current should not be an issue then, and you'd be doing the best you could. How often is panel 3 shaded, or not at all, e.g. would there be full sun on it before that of 4, 5, 9 and 10?

------------------------------------------------------------------------------------------------------------------

On a separate topic, can see this thread getting busier from today, now that figures have landed for the new price cap on both gas and electricity. Just in time to get quoted huge sums of money for a system then might have got 50% cheaper only 9 months ago, therefore making the payback time as long as before they might have considered installing it on a cost/price basis. I don't know whether that is sad or good, as we'll be generating more renewables as the bonus.
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Thanks Journey - you've agreed with my option 3 :-). Panel 3 isn't really affected at all. I have asked the neighbour to demolish her house - but up to now she's refusing.
 
If you are getting optimisers (tigo?) surely you want to get both strings up and running asap.
If you put 3,4,5,9,10 on one would it not delay 3 kicking in until the sun is higher, than say 1,2,3,4,5 on one string where it should kick in earlier and 4 and 5 would start to add in as they came out of shade?

Actually reading again it sounds like the inverter is a little on the edge for your setup with two strings.
Whats the max voltage? If its 400+ I think I would ask the installer if one string is the way to go personally
means it should kick in far faster as the sun rises surely?
 
Update on mine, Fronius inverter dead RIP, new inverter fitted yey!, Oh wait new inverter cant cope with the 750V solar voltage, keeps tripping out soon as the sun comes out DOH... so as of now solar is only working when its cloudy of the voltage is less than I think 650v.

Another 3 week wait before it can be swapped out for the correct voltage capacity inverter.

What a wind up.
 
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