Solar PV Hints, Tips & Troubleshooting

Hi All, so as solar only was installed in Nov, PV production has been some what limited. Now i have been charging batteries at night and then using during the day. I thought i was just managing it well by turning on appliance when batteries topped up to full again during the day as I have never have actually exported anything to the grid. Now today i have noticed that my battery was filled to 100% by 1117am and the graph shows that the Solar PV production has dropped right down to just 182w on each string even though the sun is shining brightly no different to earlier when I was getting 1500-2000w. SO it is obvious that the solar pv panels are not continuing to produce their maximum and exporting the excess to the grid. I'm really annoyed now as I feel that my production figures are not actually true since mid November if this has been happening. Has anyone else experienced this and how do i fix it? Is this a setting on my solis inverter or do i need the installers back to fix? Thanks

Yes sadly. See the elevated voltage and lower current. That usually is a tell tale sign of shading.

I was also worried abou tthe Backflow setting - but indeed mine is set to 0 as well. Many of the Solis videos and guides meniton chnaging this - but they are also aimed at different countries setup.

Ive decided NOT to seek any firmware upgrade or to change my current setup as mentioned above. My battery has gone to 100% via the Sunshine last 2 days - and as expected will export to grid if theree is no house load. I did notice that it takes a "good while" for it to move from 99% to 100% even with over 1Kw shining down on it. SO the tiny amount of power Im feeding it from the grid at night would take much much longer obviously.

I still dont know exactly what will happen when at night, charging from grid i reach 100% battery - but tbh IM ok with my current result as is.

When you say degradation, what happened the batteries?

Are they not covered by some sort of guarantee?

So Solis came back to me today and told me to check the export power setting and said to turn it to off. Mine was turned on so that was likely the issue. I wont know for sure until the next sunny day but it looks like that was the cause.

So i guess to ensure excess power is allowed to be exported to grid and maximum yield be achieved you can do it one of two ways:

• Ensure Export power set is turned off OR
• If export power is turned on then ensure the export power setting is at +4900w (assuming 5kw inverter capacity)

First electric bill minus a week before the solar was installed.

Previous units used 420 day and 607 night

Current units used 183 day and 556 night

Saving approx. €39 on previous bill although not a true reflection as the prices went up about midway through that cycle.

Using less than half of the days units and slightly less night. Night units are not such a big difference as we would be charging the battery at night with less EV charging so balances each other out.

Would expect the night units to come down when longer evening are here and the battery will not be charging at night.

I'm having a similar issue. I got my panels installed in August and I'm just comparing my output with all of the posts here in the thread and mine is way off what seems to be the norm. I'm in north Roscommon but there can't be that much variance.

4.3kwp East West split. (2.16kwp equal split as house faces almost due west).

49.8 Kwh for November

16.6 kwh for December

Coming to the end of January and total production is 31.2 kwh

Those figures don't make sense in comparison to similar size systems, smaller systems etc producing multiples a lot bigger.

Are the east/west panels on 2 different strings or are they combined together into one input on your inverter ?

is there shadowing on your panels in winter ?

can you see the voltage outputs to inverter on app ? This might tell you what’s happening with output.

i have one south facing string (12 x 300W panels ) and one west facing string (four panels) on different strings into my inverter.

the west facing contribute very little in winter but the south give a decent output in winter (dec = 97KWh, jan = 120 kWh)

Thanks for the pointers.

They are on two different strings, on the app/website I have PV1 (East) and PV2 (West).

There is no shadowing on the panels. I can see the voltage inputs to the inverter and they are almost identical. The screenshot is from yesterday. I'm guessing because you asked, that these should be different. Looking back through other days, they are all mirror images of each other with small variance.

The first one is from yesterday. The vast majority of output graphs between November and January look similar to this. There are a few where the output from the west facing panels was higher in the afternoon when there was late afternoon sun. But most mirror each other fairly closely. Unlike the August one above which was the day after the installation.

Roof is at 30 degree angle. Have a chimney on the roof but not directly beside panels, so not a problem. It might not be a huge amount, but mine is only producing about 50% of yours. It only produced 16kwh in December. I'll have to contact the installers and get them to have a look at it.