Shedhenge

[spread-tee]

Oh yes definitely gas approved, I'm not saying which gas mind Works a treat installed on the first floor bedroom and did make a big difference to the ground floor as well, the lofty doesn't get too hot as it is super well insulated. It is the 9000 BThU unit which seemed to be using about 600 Watts today while the PV was knocking out about 390 ish, so provided we are careful with the timing we shouldn't break the bank.

Desp

[spread-tee]

Hallo folks, I need to stop procrastinating and order up the PV kit from Bimble but to be honest I am nervous about spending 5 grand plus on stuff that is a bit out of my comfort zone, so if you would oblige with a few more questions I would be grateful.

We have lots of roof but as it is a hip end with a dormer and two veluxes and a bunch of solar thermal it isn't very friendly to the 375 watt Canadian panel sizes, so two questions :-

Do all the panels on a single string have to be the same size/output or doesn't that matter?

Do all the panels on a single string have to be at the same inclination??

Also we could have panels facing east , south and west in various quantities, but most inverters I have seen only support two strings, so what are the options in this case?

Thanks in advance,

Desp

[MoSTiE]

So...

Do all the panels on a single string have to be the same size/output or doesn't that matter?
it would be preferable, unless you were going to throw them up out in the garden to tinker with, then it wouldn't matter but if i was doing a proper roof install then yes

Do all the panels on a single string have to be at the same inclination??
Again it might work but in my opinion ... yes

Also we could have panels facing east , south and west in various quantities, but most inverters I have seen only support two strings, so what are the options in this case?
Just get 2 inverters with 2 MPPT inputs, the Solis ones have the lowest startup i've seen, just add up the voltages of the string to make sure.

[nowty]

You can have a string with a mixture of panels with different voltages as long as the current is the same or similar. If you put one in with a much lower current output it brings the whole string down to the lower current, although the string voltage rises to some extent to slightly compensate. So preferably the same panels or very similar specs of different brands.

All panels on a single string should face the same direction and inclination but small changes (like say 20 degrees) wont matter much. You can put two equal strings facing different aspects into a single MPPT, Nowty Towers uses this technique and it works. I say equal strings, they can vary by a few volts because there is some leeway around the max power Voltage point.

So with a dual MPPT inverter, you can put the South string in one MPPT and equal East and West strings in parallel into the second MPPT.

For example, these two strings are in parallel and feed into a single MPPT.
These 5 Panasonic ones are 45 degree angled and face SW.


They are in parallel with these 6 Hanwha ones at 10 degrees angled facing NE, both strings are within 10V of max power V, but have different currents.


If you have a seriously troublesome roof you can go Solar Edge with optimisers so panels in a whole string can have different inclination, different aspects and shading. You can also use TIGO optimisers just on the odd shaded or single panel facing the wrong way.

Like I've added this wall mounted one with a TIGO into another string.

[AE-NMidlands]

Like I've added this wall mounted one with a TIGO into another string.

The weather this summer has made me seriously rethink my priorities... I have a south-facing solid wall with effectively no insulation and an adjacent east-facing wall (LHS of pic) which is mostly window (or internal wall.) The south-facing walls are now warm to the touch on the inside, as are the east-facing bits (which I hadn't planned to insulate as a) most of it is double-glazed window and b) it loses the sun before midday.)
Some of the internal surface temperature will be picked up from the room air temps, but we have been keeping the curtains shut when the sun is shining in...
Nowty's picture makes me wonder whether I should bring my EWI for these 2 walls forward and plan it to include mountings for a S-facing vertical array at first-floor height? It would work best in winter, and in summer would also provide an extra energy-absorbing skin which could convect excess heat away from behind it (and from in front, I suppose.)
Thoughts?
A

[spread-tee]

Mostie, Nowty, thank you so much for your thoughts, I think I will crack on with the south and west facing strings as they are a lot easier to access, but will order up the extra panels for the east and remaining south facing panels for a later project using the optimisers if needed. Or maybe a second string on the woodstore roof coupled with the existing shed array

AE, are you planning to install the EWI yourself? it is a lot easier than many people think, sticking the panels, beading and mesh up and spreading the basecoat is well within the capabilities of a competent DIYer and doesn't need any special tools, then you could get a Spread to put on the topcoat and make it all look nice, the gear doesn't cost too much either so as a mainly DIY project it pays back pretty quickly. Just set some timber pattresses onto the wall where you need the mountings for the PV and photograph them before you cover them up then you are good to go.

The EWI shop has a calculator to cost and quantify the stuff you need to give you a good idea of the budget too.

Desp

[Mr Gus]

There are London based courses on that And EWI site, am thinking about it myself seeing as I shuffled kit off another member (still doing internals though)

If anyone wishes to make a day of it on a group day out perhaps we could strong arm a discount

[AE-NMidlands]

Thanks Mr Gus and Desp
I am thinking of DIY, and the course is very tempting, plus a bulk-buy, or even just meeting up there. The basics look pretty straightforward but I'm particularly interested to find out about detailing and fitting in around services.

I have almost no eaves (see earlier photo) just a barge-board fitted against the rafter ends flush with the wall so I am planning a roof extension.




The upper blocks are just to see if the shape works, there will be an upper "wall-plate" as well. I'm thinking of screwing the spacer blocks to the wall-plates from "behind," then screwing the wall-plates to the walls with the attached blocks (off scaffolding) then fitting the bottom and sides (soffit and fascia?) after that.
This will both let me fit a wider gutter (overdue ever since the house was built) and make space for 4 or 5" of EWI below it, but first I have to deal with the soil pipe and vent stack. I could just saw it off and fit a mushroom in the short term, but those seem to be for interior use. Long term I have to get it past the roof extension and the wider gutter, also work out whether it can be boxed in or whether it needs moving outside the EWI.

SWMBO thinks I'm going completely over the top, (and I confess I do usually over-do things - but they very rarely go wrong!) but I can't see how to do it otherwise without a big wet-attracting step at the top of the EWI - and the gutters would still be inadequate and overflowing into it!
A

[spread-tee]

Hi AE,

there are a couple of ways we have used to deal with the lack of soffit, one way is to remove the eaves tile course and the facia to expose the rafter ends and then fix an extension made of the same timber section as long as you need, and then fix a new facia/soffit and gutter. This would lower the soffit a little but you seem to have the needed clearance above your window to cope. The other option is to bevel the top of the insulation and fix a flashing to weather-proof it, this is a lot easier but does leave a bit of the wall with less insulation and doesn't look as good IMO.

The soil pipe could just be butted up against which again leaves a bit of the wall exposed, or if you want it could be cut off at low level (or even underground) a pair of 45 degree bends and space it off the wall the required amount for your insulation, it is alre3ady plastic so not a big job at all.

Having said all that it would be a shame to loose the Flemish bond brickwork, fancy a go at brick-slip cladding??

Anyone thinking of dropping in at the Chessington EWI branch is always welcome to pop in for a cuppa, we are only a couple of miles away. Drop us a PM and I will put the kettle on

Desp

[AE-NMidlands]

Hi AE,

there are a couple of ways we have used to deal with the lack of soffit, one way is to remove the eaves tile course and the facia to expose the rafter ends and then fix an extension made of the same timber section as long as you need, and then fix a new facia/soffit and gutter. This would lower the soffit a little but you seem to have the needed clearance above your window to cope. The other option is to bevel the top of the insulation and fix a flashing to weather-proof it, this is a lot easier but does leave a bit of the wall with less insulation and doesn't look as good IMO.

The soil pipe could just be butted up against which again leaves a bit of the wall exposed, or if you want it could be cut off at low level (or even underground) a pair of 45 degree bends and space it off the wall the required amount for your insulation, it is alre3ady plastic so not a big job at all.

Having said all that it would be a shame to loose the Flemish bond brickwork, fancy a go at brick-slip cladding??

Anyone thinking of dropping in at the Chessington EWI branch is always welcome to pop in for a cuppa, we are only a couple of miles away. Drop us a PM and I will put the kettle on

Desp

Thanks, I will probably take you up on the offer of a visit and a cuppa.

However our rafters are sawn off horizontally (underneath) and nailed down to the wall-plate, leaving no thickness of rafter to fix to or extend! Hence my over-engineered construction/solution (not "bodge") to get round the original problem - a fascia just nailed or screwed to the wall and wall-plate! It's actually upside-down skirting board This will also deepen the roof for more pv...
There is more English Garden Wall bond on the side of the house, the front is Ruabon Red brick in Flemish bond, so I was thinking that it wouldn't be a big loss to have one or two similar-coloured plain rendered faces.