Solar Gurus, please disect!

[SimonD]

Just got an email from my standing seam roof supplier but the followings stick on solar panels. I have no idea about price but given the shape of my roof, this could be a solution. At about 17.5% efficiency are these any good?

https://bipvco.com/flextron/ 

[JohnMo]

Solar and efficiency isn't really that important, it's just a measure of output compared to possible irradiation. So panels are bigger compared to 25% efficiency. As long as you have space, no issues.

 

From what I have seen price wise not a cheap solution - but maybe your only solution. Will you get payback? Maybe a long one. Would just a battery give a better bang for the buck? - possibly.

[Nickfromwales]

6 minutes ago, SimonD said:

Just got an email from my standing seam roof supplier but the followings stick on solar panels. I have no idea about price but given the shape of my roof, this could be a solution. At about 17.5% efficiency are these any good?

https://bipvco.com/flextron/ 

£/w cost is higher than generic, so ROI is lessened.

 

I have asked a few solar partners about these and they say the panels will likely have degraded somewhat by the 15 year anniversary, but also say these do eventually begin to become ‘un-stuck’ with heat / cool cycling over time.
 

The pro is they look a lot nicer obvs. 

[SimonD]

9 minutes ago, JohnMo said:

Would just a battery give a better bang for the buck? - possibly.

I'm rapidly beginning to wonder if battery first step is the way to go and just use the TOU we've got and rarely use our full allocation. 

[SimonD]

8 minutes ago, Nickfromwales said:

I have asked a few solar partners about these and they say the panels will likely have degraded somewhat by the 15 year anniversary, but also say these do eventually begin to become ‘un-stuck’ with heat / cool cycling over time.

This is definitely my concern particularly given the length of our panels and the expansion I had to account for when I installed the roof - I just wonder how these pv units can cope with this over the long term.

[Nickfromwales]

1 minute ago, SimonD said:

I'm rapidly beginning to wonder if battery first step is the way to go and just use the TOU we've got and rarely use our full allocation. 

Can you get a handful of PV panels on a garage / outbuilding / ground-mount?

[SimonD]

Just now, Nickfromwales said:

Can you get a handful of PV panels on a garage / outbuilding / ground-mount?

I've got max 7m x 2.2m minus a velux window which I can easily remove or just panel over on a south facing garage roof and could double that if I went with north facing panels. But this gets shaded by the house in the winter - so could use mini inverters. Then I've potentially got a 3.5 x 2.5, garden room roof but that's right at the other end of the garden compared to the garage. 

Just accepting the limitations of the garage, plus adding some batteries could be the first step, accepting the limitations.

[Nickfromwales]

6 minutes ago, SimonD said:

I've got max 7m x 2.2m minus a velux window which I can easily remove or just panel over on a south facing garage roof and could double that if I went with north facing panels. But this gets shaded by the house in the winter - so could use mini inverters. Then I've potentially got a 3.5 x 2.5, garden room roof but that's right at the other end of the garden compared to the garage. 

Just accepting the limitations of the garage, plus adding some batteries could be the first step, accepting the limitations.

Forget the north side, and use those panels on the second building. 
 

Defo MI’s, and then you can put them all on one string to simplify.

[JohnMo]

37 minutes ago, Nickfromwales said:

somewhat by the 15 year anniversary

Generally a thin film technology with a 15 year life. But can perform better than mono crystalline in low light conditions. But worth now days, most likely not.

 

28 minutes ago, SimonD said:

battery first step is the way to go and just use the TOU we've got and rarely use our full allocation. 

We runs ours on Cosy tariff, so you can actually size to meet just under 1/3 of peak winter consumption, as you get cheap periods to run house and charge the battery. Rest of the year I just charge to 60% and it does fine, never discharged low and never fully charged to help life of battery. We are paying 10p kWh instead of near 27-30p.

 

Plus get a compatible battery to allow you to join a VPP scheme (virtual power plant) and earn £1 per kWh on export events. Helps justify pay back a little better.

Edited 9 hours ago by JohnMo

[saveasteading]

1 hour ago, SimonD said:

standing seam roof supplier ....... the followings stick on solar panels

I'm no expert on solar but am on metal roofs.

Never make holes in a standing seam roof.

Are these glued on for that very reason?

And no cables penetrating either I hope.

 

Is there a spec on how they fix it? Very clean and dry roof as default.

And mention of effects on galvanised or plastic coatings?

[SimonD]

10 minutes ago, saveasteading said:

Never make holes in a standing seam roof.

Would never dream of it - I actually installed the whole roof myself so there is no way I'd let someone touch it in a way that would compromise its integrity. 

 

 

11 minutes ago, saveasteading said:

Are these glued on for that very reason?

And no cables penetrating either I hope.

Yes, that's the idea and also because curved standing seam roofs are so common. But following my research I have a feeling the industry has a bit of a problem with the standing seam clamps. Many of them essentially have a lip and use a grub screw, or some other type of vice clamp. The grub screw versions I wouldn't used on mine because this would almost certainly damage the coating and also potentially damage the galvanised surface. So either which way there are risks. 

 

 

15 minutes ago, saveasteading said:

s there a spec on how they fix it? Very clean and dry roof as default.

Apparently it has been designed for retrofit - but I have some questions about how this would successfully meet the real world of a standing seam! Most other similar products are factory bonded.

 

 

16 minutes ago, saveasteading said:

And mention of effects on galvanised or plastic coatings?

Apparently fine - it's suggested that it would be fine with my Greencoat PLX roof - but would need to confirm this with the manufacturer as they even had some very clear instructions on the type of sealant that's acceptable in the double seam - which is required in some installation instances where there's a very shallow pitch such as mine. 

[SimonD]

44 minutes ago, JohnMo said:

We runs ours on Cosy tariff, so you can actually size to meet just under 1/3 of peak winter consumption, as you get cheap periods to run house and charge the battery. Rest of the year I just charge to 60% and it does fine, never discharged low and never fully charged to help life of battery. We are paying 10p kWh instead of near 27-30p.

We're on Octopus intelligent go, so just going through a calculation to understand our usage patterns. We're currently paying average of about 17p/kWh so there's room for improvement.

 

45 minutes ago, JohnMo said:

join a VPP scheme

I will look into this.

[SimonD]

57 minutes ago, Nickfromwales said:

Forget the north side, and use those panels on the second building. 

 

Good point.

 

57 minutes ago, Nickfromwales said:

Defo MI’s, and then you can put them all on one string to simplify.

The hybrid inverter I'm looking at has dual string capability, so I can run the south face on one string and then use MIs for a second string without compromising efficiency. These MIs cost a pretty penny don't they so if I can reduce this it would be good!

[Bancroft]

2 hours ago, SimonD said:

Just got an email from my standing seam roof supplier but the followings stick on solar panels.

These look to be the same roof panels that Catnic are using for their solar roof solution (both sites show the same photo so it's either that or one of them is being loose with the truth!).

 

Catnic were, I think, the early adopters of these panels but I'm seeing other suppliers entering the market now.

 

Speaking with reps about this, they can be bonded to the steel panels in the factory or applied afterwards.  The roof manufacturer's preference is factory bonded, naturally, and I would have thought that they would be longer lasting in terms of stickiness but if the roof is already thre then options might be limited.

[JohnMo]

54 minutes ago, SimonD said:

will look into this

I am using Axle VPP. 3 events this month so far.

[saveasteading]

1 hour ago, SimonD said:

but I have some questions about how this would successfully meet the real world of a standing seam! 

I think you know more about this than the solar people. The sales people have seldom been on a ladder.

It's clear you will keep control.

 

Having been working with tyvek lap tape today, I'd suspect it could pull off some plastic coatings OR be impossible to remove at end of life.

[SimonD]

38 minutes ago, saveasteading said:

I think you know more about this than the solar people. The sales people have seldom been on a ladder.

It's clear you will keep control.

 

Having been working with tyvek lap tape today, I'd suspect it could pull off some plastic coatings OR be impossible to remove at end of life.

Yes, I dread to think about 1) what it'll take to clean a standing seam roof that's been on for 6 years prior to installation and, 2) what it would take to clean to roof when replacing the panels - at end of life or following premature failure. It just took me 20 minutes to clean the old adhesive off a Festool saw guide rail to put a new splinter guard strip on! 

[Dillsue]

2 hours ago, SimonD said:

The hybrid inverter I'm looking at has dual string capability, so I can run the south face on one string and then use MIs for a second string without compromising efficiency. These MIs cost a pretty penny don't they so if I can reduce this it would be good!

If you're looking to hook up panels to the inverters second MPPT dont use micro inverters as they push out AC whereas your inverter is needing a DC input. Optimisers is what you want if you're connecting to the MPPT input.

 

I don't know how much Tigo optimisers are but I beleive you can use solaredge optimisers with any inverter if you turn off the safe shutdown function with a Solaredge optimiser Key. You can pick up SE optimisers off eBay very cheaply if youre prepared to wait. Last time I looked the Key is about £80

[saveasteading]

There should be clamps designed for every standing seam product, allowing you to use standard solar panels.

The downside is you lose sight of your expensive roof.

[SteamyTea]

Why do you want PV?

I very much suspect that stick on flexible panels will be cost effective.

 

[JohnMo]

6 minutes ago, SteamyTea said:

flexible panels will be cost effective

Just looked at cost of flexible stick down panels - scary prices.

[Nickfromwales]

2 hours ago, Dillsue said:

Optimisers is what you want if you're connecting to the MPPT input.

I was sleeping on my feet, and meant to say this earlier…. 

[Dillsue]

3 minutes ago, Nickfromwales said:

I was sleeping on my feet, and meant to say this earlier…. 

Don't think you were napping....... MIs were an option til Simon mentioned connecting to an inverter

[SimonD]

3 hours ago, Dillsue said:

f you're looking to hook up panels to the inverters second MPPT dont use micro inverters as they push out AC whereas your inverter is needing a DC input. Optimisers is what you want if you're connecting to the MPPT input.

 

Thank you for the heads up! I just checked back a realised I'd got a couple of things confused. The MIs had been specced donkeys ago for a system that was also on the main roof and included the south face of the garage to account for the predicted shadowing over the year! This plan never got anywhere because the solar designer couldn't find a roofing contractor that would touch our roof and standing seam.

So, yes, scrub the suggestion of MIs into the inverter.

[SimonD]

2 hours ago, Nickfromwales said:

I was sleeping on my feet, and meant to say this earlier…. 

 

2 hours ago, Dillsue said:

Don't think you were napping....... MIs were an option til Simon mentioned connecting to an inverter

 

I think I was the one napping. When I was asking about the inverter I was told it had two MPPT strings so I could run the north face on the second, not using MIs - that bit was me being dopey.