low output until all panels in sun

[davey_b]

We have two arrays here, one with solaredge inverter and optimisers and one with an SMA TL inverter spilt into strings designed to minimise the effect of shading on the array as a whole (i.e one string connected to one of the MPP's gets 'hit' the worst) with optitrac enabled, both get very similar shade. To the annoyance of solar edge, it is very difficult to tell the difference... (there are other technical reasons for installing one of the arrays with solaredge)

Well there we go. It seems that the most straightforward, easiest and cheapest option is fit sma inverter.

 

[Worcester]

Possibly, though you will also want to sort it out into strings that get the worst / best shade / sun.

You should also have a string test doen to see if there are any faulty panels / miss wired strings, your current inverter may have two strings (and one MPP tracker) thouh how have they been physically wired? You want to put all the worst affected panels into just one string, so that will at a minmum mean a good crawl on the roof and look under the panels to see if you can see how they've done it. Most likely it will mean taking at least half the panels off and re-wiring them in the best order. So whilst you've got them off.... what would the cost of optimisers and control box be vs a new inverter...... probably very similar, though the latter may be less actual work.

 

[davey_b]

Possibly, though you will also want to sort it out into strings that get the worst / best shade / sun.

You should also have a string test doen to see if there are any faulty panels / miss wired strings, your current inverter may have two strings (and one MPP tracker) thouh how have they been physically wired? You want to put all the worst affected panels into just one string, so that will at a minmum mean a good crawl on the roof and look under the panels to see if you can see how they've done it. Most likely it will mean taking at least half the panels off and re-wiring them in the best order. So whilst you've got them off.... what would the cost of optimisers and control box be vs a new inverter...... probably very similar, though the latter may be less actual work.

I'm thinking more for the installer as I expect them to come and do this and pay for it. They could reuse my solarmax inverter on another job that has no shading and give me an SMA one that works with shading. Cheapest option for them by a mile.

 

[Worcester]

The regulations say that they can't re-use equipment defined as panels and inverters that have been once installed on a FiT registered installation on another one. One questions their competence to make any sensible decision or recommendation though, and I wouldn't be suporised if they tried to do that to the detriment of someone else....

Where are you with the conversation with your installer and what have they offered to do so far?

You have all the advice, it's now time to get it resolved...

 

[davey_b]

Emailed them yesterday but the manager is off this week so we'll see what comes next week.

 

[Gavin A]

Well there we go. It seems that the most straightforward, easiest and cheapest option is fit sma inverter.

Aurora Power One have the exact same shading functionality and dual MPPT set up, but for a fair bit less money.

Attached is one we installed earlier, with hard shading from next door house coming across the array from 5.40pm. full scan function set to 5 minute intervals on Aurora power one 3.6 Out-D, as the performance at 15 minute intervals was terrible, and I've approximated the shaded and unshaded production lines for comparison. The shading actually happens almost exactly as per our model, as does the performance.

btw can I ask, how did you end up choosing this company to install your system? This sort of situation is the entire reason that this recent race to the bottom with solar is a really bad idea,along with the get 3 quotes mantra - getting 3 quotes is all very well if people go with the best company, but far too often they're just going with the cheapest and assuming that solar is just simple technology / ignoring the benefits of going with an experienced well trained installer even if it might cost a little extra up front.... or often actually, people end up buying from some smarmy sales person who knows nothing about solar, then wondering why it doesn't all work out well for them.

Let this thread be a warning to others, if you buy from a company who doesn't know what they're doing, then it can all go very badly wrong for you especially where there is any shading involved.

I do hope you get this sorted, but at the same time, I can't help but feel that maybe you contributed to this by choosing a company that didn't know what they're doing for some reason, then expecting the experienced installers on here to assist you for free down the line when it's all gone wrong - the same experienced installers who're being undercut by the sorts of idiots you got to install for you.

Apologies if you think this is out of order, but I have had an ale and am going to get on my soapbox for a minute, as this is a serious issue for the industry and our customers and potential customers.

It's an example of why cheap / big but know nothing companies aren't always best. We recently took someone on who'd been British Gas trained for solar and worked for them for 18 months, then worked for another company, so total 2.5 years solar experience, mainly with SMA.... he'd never been shown how to set up the optitrac global peak shading function on their inverters, or even told that it existed.

As a counter point to that, we trained our guys in it within a few days of it being released, and bought laptops specifically for them to use to set this up, and went back to upgrade a lot of customers inverters with the updated firmware within weeks, which really is the difference between a highly specialist company, and some fly by night, or big company that's decided to move into solar.

If you have shading, then please find a company that really knows their stuff to deal with, otherwise this sort of situation will very likely be the result. Solar is not simple, it can not be learnt properly via a 3 day course led by trainers who've only done a couple of installs themselves, or have competence properly assessed by assessors who've only done 5 installers themselves.... unfortunately that makes up much of the industry, and is all the MCS requires, so as a customer if you have a complex install you really need to make a judgement about whether the installer seems to know what they're talking about or not.

tbh this is more of an indictment of the industry regulators than anything, unfortunately the public get misled into thinking that all MCS companies must know what they're doing, when the reality is very different - MCS is no guarantee of quality or competence, it's basically a minimum standard, and you're left to assess for yourself whether the company actually knows their stuff beyond that bare minimum standard.

I hope you get this sorted though, as far as it's possible to be sorted.

 

[davey_b]

Totally fair points there.

I was of course fairly influenced by price but I checked the company out and spoke to previous clients. To be fair to them they've not yet had a right to reply so we'll see what their response is.

 

[davey_b]

Had the guy out today and to be fair to him he was really decent and is keen to get this sorted. He's said we can have a different inverter and has said sma sunny boy and aurora power one both have technology to deal with shading. I think sma has software to track the global peak whereas aurora has 2 mppt.

So the question is which one is best to go for? Any thoughts?

 

[telectrix]

i'd be buying one of these babies.

 

[Worcester]

Power-one also has software to specifically cope with shading across multipel strings. As with the SMA inverter, you have to specifically switch it on.
Power-one on-screen configuration, SMA via the sunny explorer software. In your case, I would slo check that the installler has the knowledge as to how to do this - or even if they know that the functions exists beyond the twin MPPT. Additionally with Power-One you can manually change the re-scan interval time to check it has the best value (it time it scans the output will be affected as it searches for the best value)

Horses for courses. We've installed both!

SMA has easier and better monitoring built in and with Sunny Explorer on your PC, the display and ability to store detailed output is 'free' (you DO NOT need a 'SunnyBeam) Add in some extra free software and you could have a live link to PVoutput.org as well. Power-one is a little more complicated.

 

[digital48]

SMA has easier and better monitoring built in and with Sunny Explorer on your PC, the display and ability to store detailed output is 'free' (you DO NOT need a 'SunnyBeam) Add in some extra free software and you could have a live link to PVoutput.org as well.

Not wanting to hijack the thread, but could you point me towards the 'extra free software' please? Sounds like just what I want!

Thanks.

 

[mdovey]

Not wanting to hijack the thread, but could you point me towards the 'extra free software' please? Sounds like just what I want!

Thanks.

There's a list here: Help

but others will have to comment which of the SMA ones listed work best

Matthew

 

[taffbutc]

The top right panel apprears to be shaded at the top. this covers the full panel. the by-pass diodes are activated and causing this. Next time it is sunny take a look at the shading. take output. Then when shade goes off the panel check again. If it shoots up quickly (which is what i believe you are saying) i would move the panels to the left. Your output over the year will be improved

 

[davey_b]

The top right panel apprears to be shaded at the top. this covers the full panel. the by-pass diodes are activated and causing this. Next time it is sunny take a look at the shading. take output. Then when shade goes off the panel check again. If it shoots up quickly (which is what i believe you are saying) i would move the panels to the left. Your output over the year will be improved

Yeah that's pretty much what was described in the first post in this thread.

 

[Worcester]

Hi @digital48 - I use the sma-uploader - VB Script to upload PV data from SMA inverter to pvoutput.org - Google Project Hosting it was the simplest one to install and setup.