Shading and Solar Edge

[Inti]

Hi Guys

At a job today and quite a lot of shading with a chimney on the middle of roof and a big tree. I'v created a model on PV Sol and from that calculated the overall shading. Thinking I would use a Solar edge Inverter. The following is a series of images that show the modelling and the shading. Looking for comments on the logic of my final calcs.

First Image shows the house with panels on the south west aspect and the garage on the same (Dorma on rear of house not on model)




Second Image shows the House roof shading analysys caused by the chimney tree and probably house next door to a lesser extent.

































Third image Shows shading on garage mostly caused by tree.




And the table below takes all of the panels shading and then because there is individual optimisers on each panel I divide the shading by 10 (the total number of panels:



Any comments gratefully received

 

[Worcester]

See if enphase will do the calcs for you - they are desparate to establish a foothold in the UK..

 

[Inti]

Nobody willing to comment on the logic of my calcs?

 

[Worcester]

Nope, solaredge / enphase will give you the answer!

We have a solaredge installtion here, and I actually see very similar losses to an MPP tracked string system immediately alongside it. Despite four 250W panels in full sun the other day, the more heavily shaded (at that moment in time) MPP system was outputing more than the solaredge system.

From your drawing I would say that you are correct in considering either Solaredge or Tigo or a micro-inverter solution, however as above, I suggest you speak to solaredge for a reasoned response to their acceptance of your figures.

 

[Inti]

Sorry guys, I just thought that if someone was experienced in using this system they would be able to confirm if the logic of my calcs was sound or not.

I have taken a simplistic view that if a panel is shaded by 10% then because every panel has its own inverter the panel would be unaffected by anything else and would therefore produce 90% of the time.

So my basic calculation simply takes this theory forward for each panel and adds them altogether to get a total. Simple.

It would seem that no one would care to confirm this is sound logic or not. Does this mean that no one knows?

I have sent my report to Solar Edge and waiting a call back from Enphase and will post my findings when I get them.

 

[Inti]

Sorry guys, I just thought that if someone was experienced in using this system they would be able to confirm if the logic of my calcs was sound or not.

I have taken a simplistic view that if a panel is shaded by 10% then because every panel has its own inverter the panel would be unaffected by anything else and would therefore produce 90% of the time.

So my basic calculation simply takes this theory forward for each panel and adds them altogether to get a total. Simple.

It would seem that no one would care to confirm this is sound logic or not. Does this mean that no one knows?

I have sent my report to Solar Edge and waiting a call back from Enphase and will post my findings when I get them.

Asked very specific question about shading and how individual panels are treated by Solar Edge got back this reply:
Hello,

You can use our Site Designer Toolif you want to calculate your production:

http://www.solaredge.com/files/zip/solaredge-site-designer.zip


We do not use / Support any otherDesign tool.

Best Regards,
Tal.


Complete waste of time!!.

Enphase phoned me back and simply agreed with me but the guy I spoke to didnt really fill me with any confidemce. I tried to involve hin in conversation on the subject and found out he hadn't even heard of Solar Edge which was very strange considering they must be their main competitors.

I have written back to Solar Edge and asked again but I wont be holding my breath.

 

[Inti]

Actually got a very quick response fro Solar Edge who have confirmed my cals with the following reply:

"Using a standard inverter wouldprobably deem this system uneconomic because there
would be a degree of shading on oneor more panel for a large part of the day and shading
on one panel brings every otherpanel down to the lowest output level.

Using Solar Edge technology everypanel has its own optimiser which means only the panel
that is shaded has lower outputwhilst all other un-shaded panels will produce maximum
results."

 

[Worcester]

"all other un-shaded panels will produce maximum results"

That's the theory, it's not quite what we are seeing in practice... we are seeing lower outputs than that. I'm not saying that they are not better than what you'd get from a string inverter, just don't believe all the hype.
​

 

[Eco Deal]

Worcester I have installed 100's of solar edge system and in shading situations they are much better than a string inverter.

The prices from SMA to solar edge is not much between them now , Id just pay for solar edge for extra warranty of 12 years over SMA 5 years and online monitoring !


how much is a web box £300 - £400

so solar edge you got 12 years warranty
online monitoring FREE

plus indivdual MPPT's

a major benefit that every one over looks is you can mix and match panels

so think about it if you have a string inverter and in 10 years time a panel goes faulty what are your two options

remove panel from string or buy same panel (but will the panel you get today be on the market in ten years)

with solar edge you could just get a panel that looks the same as the other on the roof.

there is a down side to solar edge which is you have upto an extra 16 items that could go wrong .

we have had two power boxes go down now .....

 

[Worcester]

@MEP Elec, I know you're a great fan of SolarEdge, and I also strongly believe that they have their place / uses.

I have a real life back to back installation solaredge vs string. The string one is actually in worse shading (trees to be trimmed in spring ) I'm just not seeing the kind of improvement that I would have expected from the claims / way they are supposed to work.

Our Solaredge installation has allowed us to mix and match panels - that's why we installed it ..

 

[Worcester]

For SMA - got a pc and a bluetooth dongle? - don't need a webbox - free software and live monitoring on pvoutput.

 

[Worcester]

We're about to install 5 minute monitoring on a single platform, than I'll be able to give you a real set of back / back results.

 

[grandfortune]

Our Solaredge installation has allowed us to mix and match panels - that's why we installed it ..


Sry to jump on the post , Worcester why would you mix and match panels?

cheers grand

 

[Worcester]

Because we had lots of 'end of containers' / end of pallets left over

Attached two systems same size (4kWp, one Solaredge, and on SMA String Inverter on 2MPPT's) image compares daily output / kWp installed, string installtion is actually in worse shading ....

We took the string system down for a day to do some rewiring hence the gap on one day.

 

[poheZ]

i would agree

We have done about 12 solar edge installs and they all seem to be performing the same or worse than our string inverter installs.

 

[Eco Deal]

yes with sma you can have sunny explorer but you can not monitor the indivdual solar panels , which I really like.

dont forgot every property is diffrent so you can not really compare unless you set up experiments etc.

 

[Worcester]

@MEP thats precisely why these two systems are set up alongside each other... As per an earlier post the reason we choose to use the solaredge was becasue of the fact that we have mixed panels. So the choice was Solaredge, Tigo, Enecys, Enphase or Involar. Tigo threw their hands up and said theirs wouldn't work, of the rest Solaredge was the cheapest....

 

[gr7]

I'm glad I read this thread. We were about to quote on a system using solaredge to get around seasonal shading from an adjacent property. Given the results Worcester has provided, I think I'll stick with SMA.

@worcester - can you tell me whether OptiTrac was enabled on the SMA please?

 

[Eco Deal]

as you know I still prefer a solar edge system over sma any day any situation not just for indivdual MPPT's

warrantys
mixing panels
online monitoring (each panel)
safe dc voltage
remote fault finding is possible to.

down side as I said 16 more items that could fail

 

[gr7]

Whilst I understand these benefits I am still concerned about your earlier post stating that you have had 2 power boxes go down. Accessing and removing a panel to change a power box would be time consuming, expensive and awkward on most installations.

 

[Worcester]

Re optitrac, no it isn't! So we may get even better performance.

as MEP Elec says, module based power management has its place and we will always consider it as an option.

 

[gr7]

It would certainly be interesting to see how your systems compare with optitrac turned on.

The shading on this job will only affect the array between Nov-Feb anyway so I may as well go for the SMA3000TL-21 with the lower panels on a separate tracker.

 

[SolarCity]

Regarding the OP, is that General Sherman that you're planning on installing alongside? That tree is enormous!

 

[finchy]

We're doing our first solar edge soon due to partial shading at different points of the day. I like the future proof option with solar edge and the plug and play monitoring as standard.

 

[Worcester]

I can see in 5 years or so a simple panel add on that will work with any panel and you dial in the required parameters to match your replacement panel to your existing ones. Probably cost no more than £25 then. Either that or a 'universal panel' with the same technology built into the junction box on the rear.

 

[Eco Deal]

I do place the power optimizers on the Top rails or lower rails so they are only at arms length away to replace .

It took about 20 mins to replcae WITHOUT moving the panel or scaffold using ladders and cat ladder only.

So it not too bad the problem is if the install is a fair distance.

one of the Power boxes had bugs inside which I have spoke about before . the bugs where half scottish and half isreali !!!