Solar PV Hints, Tips & Troubleshooting

championc

Just in case, are you reading the right figures ? That output graph looked fine although I would agree that the voltages look odd. With low current, the voltage should increase

garo

I got 55 kWh in December. Where is the chimney located? North side or south? You'd be surprised at how long shadows are in Dec/Jan even at midday. I thought I didn't have a problem with shading but then discovered shading from the south neighbours roof - which is the same height but offset by a couple of metres.

mun1

That’s your problem, both strings are picking up the same sunlight (voltage ). I would expect the east string to pick up sun AM and west in PM .

wires are mixed up somewhere and west panels are dragging down the east panels in the morning and vice versa in the evening. But not last august as sun is higher in sky.

what angle are the panels at ? They could be too shallow for the low winter sun.

rainbowtrout

https://www.boards.ie/discussion/comment/118550870#Comment_118550870

Chimney is southside, panels are placed as far from them as possible, which I know is limited on a roof. Haven't noticed shadowing issues.

rainbowtrout

https://www.boards.ie/discussion/comment/118550840#Comment_118550840

Well those are the figures from the app for the two days I posted. E.g. on the app 22nd Dec and 25 Dec recorded 0 kwh (was at parents for christmas so not in the house to check anything). 22nd was shortest day of the year and was very overcast so wouldn't be expecting much in terms of output.

garo

That's not zero though. Maybe your app is rounding down to the nearest whole kilowatt-hour?

If your chimney is south-side I would be very very very surprised if it is not casting a shadow at this time of the year. The sun is at 19 degrees altitude at its highest which means the chimney will cast a shadow about three times as long as its height. Go out and midday tomorrow and take a look at the panels. Even if one of the panels is shaded it will bring down production on all the string.

Edit: Could a mod move the discussion here to the right thread? @DrPhilG ??

championc

@rainbowtrout we can continue discussing your issue here.

Are your wires coming into your attic ? If so, could you disconnect the negative in the attic of a known string and see if the same string is knocked out.

As @mun1 says, it could be that the two cable pairs have been mixed up

rainbowtrout

https://www.boards.ie/discussion/comment/118551389#Comment_118551389

Yes, they are, I can try that tomorrow and see what happens. Thanks for the help.

championc

https://www.boards.ie/discussion/comment/118551478#Comment_118551478

Also, a positive and negative should come into the attic from each side of the roof. There should be no link of any kind between the east and west strings.

You'll possibly need a long nose pliers or screwdriver to open the MC4 connector. Hopefully there is a connection point up there.

garo

Be careful not to pull the plug when under load. Either do it at night or switch off the inverter before doing so.

DrPhilG

Will do if I can figure out how...

DrPhilG

I think it worked, yay!

garo

Thank you! Great to have mods again.

rainbowtrout

https://www.boards.ie/discussion/comment/118551721#Comment_118551721

So to follow up, as I'm not an expert on wiring panels and inverters, I was limited in what I could do to test them, but I did switch off each set East and West in turn to see if it made a difference and I wasn't able to get any further with my conclusions. I put together my data from the app and contacted the company who installed them who got back to me within 5 minutes of me sending the email and said that yes, I was correct and there's something wrong and they will send someone out to have a look to find out what is wrong and will compensate me for the lost solar over the last few months. So I should get sorted in the next week or so. I look forward to posting some improved data.

garo

Nice. That's the best outcome.

championc

Data is king - you cannot argue with data. Lucky you took an interest in what your system was doing.

But that was exactly the reason as to why I started the monthly thread - so people could see what they were getting and what they should be getting

rainbowtrout

https://www.boards.ie/discussion/comment/118561559#Comment_118561559

To be fair, the company have been excellent to deal with and I had no issues there, and there was no argument on the phone, they said straight away there was something wrong and they would sort it and offered the compensation straight up without any query from me. I only have the panels since August so it's hard to know straight off if there's something wrong when I didn't have past data to compare to, and it was only when I was seeing people post here that I knew something was definitely wrong and it wasn't just a weird anomaly. There are no faults showing up on the system so it's something else, probably what was suggested here about the strings being connected incorrectly. Over the five full months I've had them I've produced 46% of the expected output, only it was more obvious in the winter months.

garo

https://www.boards.ie/discussion/comment/118563937#Comment_118563937

Moving the discussion from the monthly output thread @bullit_dodger

So I have a bit of shading in the morning which means my output often doesn't hit the prediction from Nov 1-Feb 10.

The 26th was my joint highest as I got the same production as the 24th.

That difference in angle makes a huge difference. Right now at 12:06 on Feb 1st your East 091 at 35 degrees has an angle of 73.87 degrees to the normal and cos of that is 0.278. OTOH for my East 100 at 24 degrees the sun is 68.53 degrees from normal and cos is 0.366 So I am getting a third more insolation than you. Over the course of the day the difference for the East/West panels is: 1.34/1.24 for you vs 1.72/1.12 for me.

Here's the sheet: play with it to your heart's content: https://aces.nmsu.edu/pubs/_circulars/CR674/welcome.html

slave1

Angle makes a big difference, I am kicking off a second array groundworks today and using galvanized tubing, 4way tilting for the seasons will be incorporated into build

bullit_dodger

Ohh absolutely Slave - angles do matter. (and smart move to incorporate 4 options of tilt, though in reality you only need 3 settings, right? Spring being the same as Autumn right? You'll get an extra 20% for the same panels doing that - though naturally for me with a fixed roof, sadly not an option.

But my point was more that 12-13 degrees difference in slope between me and garo doesn't really matter much this time of year (with an east/west split where the sun is predominantly to the south). If your panels were facing south, then yeah it would matter more, but the angle of incidence isn't affected much by this amount. To confirm plugging the same sizes panels , one with 22 deg slope and other with 35 deg slope into a forecaster tool will show you it's <0.5% for Jan!

Interesting puzzle.

samdeluxjones

https://www.boards.ie/discussion/comment/118565626#Comment_118565626

Thinking of doing the same meself, December and January rarely passes 3kw during the day so a second array added to existing system would boost it on the short days and use it in the morning and evening(on a timer) in the summer months to flatten the curve.

bullit_dodger

ECO_Mental's statistics are a great example of the benefits of a south facing ground array with a high incidence angle!!

Moneypoint basically! :-)

handpref

I just checked there and my system says zero generation for January -

I have emailed my provider to see if they can tell me anything.

After being treated appallingly after the install, grant held up for two years and then charged €1000 for the grant to be ‘processed’ I don’t have much faith in them.

I have a Givenergy system- but I’m not sure how to get the report info from each string- I do remember checking it before but with the new site layout I can’t find it, any help would be appreciated-

Lastly if anyone else has a givenergy system in and can recommend their installer I would have no problem paying for a second opinion- for a 5.4kwp system I’m thinking it could do better, but without an independent assessment I’ll never know - many thanks

championc

Are you charging your battery from the grid at night ? If so, the bottom section could well prove that you are correct.

The totals and battery info proves that the portal is being updated.

Is there any screen display on the inverter ? Is there a mechanical or fuse DC disconnect between the solar panels and the inverter ?

And when did you last generate any power (according to the portal) ?

bullit_dodger

I think there was some problem this month on the report from GivEnergy. I saw they reported it themselves that it was wrong. I don't pay much attention to the reports myself as I look at the telemetry directly. For example..... my own report reckons I generated zero for the month. LOL

If you are looking for the wattage per string it's in the "Inverter" settings and "PV data"

championc

I also keep a note of my grid meter readings, so if something was wrong, it will show up there for sure.

handpref

Thanks Bullit, I have it up on the desk top here and can’t find a pv data box -

below Is what I see - thanks for the help

bullit_dodger

Go in via the "beta site" on the login page.

And then select your "inverter" .....and there is a "PV data" tab that can show you the details for each string like as follows.....

handpref

Fair play to you, great step by step info, I was going in through the wrong portal - that string data really is hidden deep within the settings -

Can’t find any historic data log , does it exist ?

Im thinking the angle of my roof is so shallow it’s not able to do bugger all nov-dec

Always super info here - thanks to all for their input

bullit_dodger

yeah, you can use the little calender function as I've highlighted below to go to various dates.

And the other highlighted button you can download the raw data for that day and slice/dice it in Excel if you want. Overall the new dashboard site which is in Beta is way superior to the old one. Sure, something are moved about and not as "intuative" as before, but it's quite flexible.

I wrote my own scraper for the data and I've a seperate app, but can apprecaite that this isn't something that everyone would do.