Solar PV Hints, Tips & Troubleshooting

DC999

https://www.boards.ie/discussion/comment/119345404#Comment_119345404

I00%. While the solar we all bought is ours and we can use the power as we choose, what's the point heating water in a house no one is in. Will only serve to make the house warmer in summer. Better it goes to the grid so it's not lost.

Maximising what you send to the grid that you don't need is good karma in my mind :)

And if you are lucky enough to have a backwards spinning meter still, the more you send to the grid the better. As you get a temporary 1 to 1 credit until that meter is replaced.

DrPhilG

How are you all performing today on this scorcher?

I just did a quick comparison with my best ever day, June 4th when I took in 50kWh.

June 4th at 9am

Generating 1.46kW

Today at 9am

Generating 0.92kW

Difference being that June 4th was nowhere near as warm in general.

Just how badly does the high temperature of panels and inverter affect production?

Gerry

I'm only new to this, but I had read about inverters being affected in high heat. On saturday I felt production was not what it should have been, in clear skies I was getting 70% of what I expected. I checked the inverter with a laser guage which is accurate to within 1/2c - it was reading 50-55c on both the heatsink and the inverter itself. I added a small fan blowing at it and it came down to 45-47c . Its max stated operating temp is 60c so I will add something permanent there - I don't like it running that hot.

Yesterday there was far more wind, which also created some circulation in the attic, the inverter was running under 40c

I did not measure the panels, I will do today. I think wind or lack thereof would make a big difference. PV panels are generally mounted above the titles to get air underneath them for cooling, but you need a bit of wind too.

It would be interesting to see graphs of saturday vs sunday for a period with clear skies.

<edit> just wondering - do you have clear skies today? </edit>

DrPhilG

I've got clear skies, and much lower generation than I'd expect.

4kW capacity on the south facing garage and I'm only just reached 1.8kW at 10:15 on a clear day.

I'd expect it to be north of 3kW already.

bullit_dodger

It's not so much the inverter which affects production performance, it's the temperature of the panels. Most panels have a "temperature efficiency formula" where they state the drop off in performance for every 1C above 25C. Usually it's about 0.4% for every 1C. Of course if today is 30C ambient temperature, that's not of course the temperature of the panels which (being black) might be 60-70C baking in the direct sunlight. A breeze helps cool the panels, so part of the reason they leave a gap between the panel and the roof is to help cooling. You can have a read about it here.....

How Temperature & Shade Affect Solar Panel Efficiency | Boston Solar

Inverter temp in the 50-60C range isn't unusual also. My own one regularly hit 58C-59C (it's max rated is 65C). Like you I have a little fan working on it in the summer months. I don't think it will break, but at the same time a fan consuming 10-15 Watts helps "unstress" the box, so it's no harm

DrPhilG

Anyone with Solis Cloud app want to check their temperature readings?

My "internal operating ambient temperature" is 37.8° at the minute.

Hit 62 this morning when I was charging the car.

silver_sky

https://www.boards.ie/discussion/comment/119352413#Comment_119352413

42.8C here currently. Mine hit 76.8C yesterday afternoon when charging car and at the peak of the generation. Highest I've ever seen.

silver_sky

Solis Cloud managed to find my inverter over the weekend without the need to call them. I lost it when I swapped out the data logger in an incorrect way. I'm assuming they run some scripts or something to fix such issues.

Gerry

https://www.boards.ie/discussion/comment/119352409#Comment_119352409

Yup, I'd come around to the same conclusion. While my inverter temps higher than I'd like, they aren't causing the drop.

I will check temp of my panels once we get near peak ( my panels are SW facing ).

Thanks

championc

https://www.boards.ie/discussion/comment/119352388#Comment_119352388

Of course, you've a different inverter now in the mix 🤔

DrPhilG

https://www.boards.ie/discussion/comment/119352641#Comment_119352641

That crossed my mind too. Surely a newer bigger inverter wouldn't result in poorer performance?

Gerry

surface of the panels ( with full sun ) is 38c now. production got to 2.8kw ( 2.92 theoretical max ) before the clouds arrived so I'm happy enough now tbh.

DrPhilG

Interesting. Inverter internal temp peaked at 67°, then dropped sharply.

Generation seems to be have peaked at around 4.8kW at the same time.

Gerry

67c is awfully high - I'd be looking at getting a fan in place.

I've just found my inverter locally on the network, got into its local web server, which is good.. and its internal temp has gotten to 43c. The spec sheet says its good till 60c, but there may be de-rating from 45c upwards. There hasn't been sustained clear skies here today really.

So I'd try pointing some sort of fan at yours, get the temp down and see if output goes up.

DrPhilG

Way ahead of you @Gerry

This arrived today, will get it fitted in the next day or so.

Need to change that plug first.

DrPhilG

Anyone else got pictures of their fan setup?

But of a bother to mount them facing up into the inverter with this stuff in the way.

For now I've just popped it on top here facing down, and it has dropped the internal temp from 47 to 40 in less than 5 minutes.

Wouldn't want to leave it there long term mind you. Although I could mount it there once I get brackets, raise it up an inch or 2.

Edit, now down by 10 degrees.

steamdave

https://www.boards.ie/discussion/comment/119355889#Comment_119355889

If you cannot put the fans under the inverter, how about reversing the fan direction to pull air upwards?

Dave

yankinlk

https://www.boards.ie/discussion/comment/119355889#Comment_119355889

Is this inverter temp data recorded anywhere else ? Can we see a history of it thru the app? I didn't know where to find until I saw your SS... 38C this morning. Would love to know what it hit yesterday

DrPhilG

https://www.boards.ie/discussion/comment/119357338#Comment_119357338

This is my temp graph from yesterday, from the Solis Cloud app.

Very unusual, peaked at 67.5 and then dropped sharply, then eased off as the generation faded.

The bit I circled in red was when I got home. I moved the fan that was in place, and the temp went up. Bit of messing with the position explains the little dip and increase, then I left the fan on top and you see the big 15 degree drop.

Funnily enough the fan was on a timer and when it cut off at 9pm, you see the temp shoot back up from 32 to 45. At that point I noticed it and turned the fan on again, dropping it back down.

DrPhilG

And again this morning. I had the car charging a bit from 6:30 til 7, so the temp shot up to 55.

Unplugged the car and turned on the fan and the temp dived.

yankinlk

This is great thanks @DrPhilG i didnt even know i had access to all this data!

My starting point over night is 30C and it peaked at 52.6 yesterday. I dont have any cooling in place but the inverter is at the back of the house on ground floor. Anyone running these in attics or with zero air flow should take care! The room its in is also used for running the dryer and it was running around the time that the temperature peaked... dropped off when it finished and declined the rest of the day.

Meant to add yesterdays ambient temp in my area was very close to 30C.

bullit_dodger

For a non-solis inverter data point, here's my GivEnergy inverter temp for yesterday. (Highest recorded)

Normally it hovers in about the 50-55C range when under load, bit like this ....

Max operating temp is supposedly +60C, so yesterday pushed it a bit. Might look as others of you have done just getting a cheap and cheerful fan (even one of those USB jobbies) and improve the circulation at that part of the attic. Couple of days like yesteday or close to it in the high 20's wouldn't be good for it.

DrPhilG

I've got a standard room fan blowing across the batteries towards the inverter, and currently the 3 piece PC fan that I bought is blowing from the end of the batteries up towards the bottom of the inverter.

I'll get a better mounting job done soon, currently it's just sat there.

Keeping things pretty cool though even as the generation creeps up.

Batteries sitting at 26°, they were at 37° when I got home last night.

DrPhilG

Generating 184w at 2:30pm.

Something ain't right here.

79w on a 4kW south facing string and 101w on a 3.4kW west string.

Gerry

unless you got visited by the thunderstorms? if not, contact installer..

DrPhilG

https://www.boards.ie/discussion/comment/119359566#Comment_119359566

I wasn't home, but the neighbours tell me there was a wee bit of rain and thunder but nothing substantial.

Nothing that would explain sitting below 200w for long spells.

SD_DRACULA

Think someone asked for the fan setup a while ago and eventually got to the attic today:

DrPhilG

https://www.boards.ie/discussion/comment/119361962#Comment_119361962

Yup it was me asking. I'll go with something similar. Too much traffic underneath.

DrPhilG

Anyone with the Solis Cloud app who had a similarly terrible day in Tuesday fancy comparing the voltage graph?

This was mine on Monday compared to Tuesday. Monday,consistent voltage across the day, only starting to drop late in the evening.

Tuesday, lots of voltage drops where one string drops to 75v while the other stays in the 350v range.

Jonathan

https://www.boards.ie/discussion/comment/119361971#Comment_119361971

I've more panels on my string than you, but I rarely see any voltage drop during daylight hours. Attached is screenshot from today when generation stopped for a few mins during a thunderstorm. Voltage dropped, but only slightly. (Ignore the voltage rise at 17:20ish, RCD tripped).

Also attached a screenshot from Christmas Day last year when I didn't generate anything. Again voltage is reasonable consistent throughout the day despite the dull day. Something not right with your string voltage.