Solar PV Hints, Tips & Troubleshooting Part 2

I've noticed that the load on my inverter doesn't appear to be right, see graph below where the load between 08 to 12 is virtually zero and from 22 to 04 is also virtually zero — this isn't right because the house base load is minimum 300 to 500w whereas the load recorded around is .01

So is it a faulty meter? Its Acrel ACR10R

TIA

I was initially going to suggest that the ambient temperature was going to impact production today, but voltage2 and current2 are way too low for that and appear to be indicating an issue as you said. What aspects are the strings on and do you have optimiser modules fitted? Is one string shaded or badly impacted by some obstruction?

Both south facing aspect. The larger array is a ground mount and the smaller array is on a steel shed. No optimisers and no shading issue before 5pm when the shadow of an ESB pole crosses the ground array.

I've noticed 4 or 5 large blobs of bird crap on the ground array. I'll get the garden hose and a brush out later but I suspect that's not the issue.

UPDATE: Panels washed but still an issue with the ground array.

Very interesting thread. Maybe somebody can give a bit of advice.

I have a 3.6kwp Solis Inverter on a south facing roof operating as a single string, and I'd like to add a second identical inverter with two strings split between east and west.

From doing the calculations the total export could never exceed 25A as the South+East would max out at 5.5kW, and then the South+West would do the same, but my question is whether or not this set-up is permitted? Is it common? Does it require a 25A Current Limiting Device? Is there such a thing?

Thanks for informed advice.

PV2 voltage likely below the MPPT minimum for a string, meaning it won't generate, hence the zero current

I had a grounding fault in February after a few days of significant rainfall. The issue went away a few days after things dried up. I wonder is that ground earthing becoming an issue again.

The cables from the ground array are running through a duct which appeared to be quite fragile and easily cracked if dropped. I wonder has the duct collapsed underground (it's buried about a metre down) and causing the DC cable to earth ....but the inverter isn't registering the fault so I'm a bit at a loss.

following on from @graememk answer does your hybrid support monitoring of other inverters?
I have an AlphaESS Smile5 which is hybrid inverter but has a mode confusingly called "hybrid" where the CT meter is connected to a second CT meter which monitors the output from my second string inverter (or multiple string inverters). This allows my system report the generation from the other inverter and also means grid/generation/load are all calculated correctly

So the ground array is PV2 and is larger than PV1 ? So what should it's voltage really be ?

The first thing that I would do is to measure the voltage of the string at the panels before the cable goes underground.

Approximately, what should it be ?

I had a dead fireman switch last year. I have 2 inverters and 2 fireman switches. Meant one inverter was offline. Powering off the AC and DC isolator and fireman switch didn't resolve.

Installer replaced at no cost. I expected to pay labour but fireman unit has a 5 or 7 year warranty.

And bearing in mind that ~500v DC is potentially present. 👍️

Let's be cautious here. That adage is correct to a point.

While testing a solar system with an MPPT input rated up to 600v DC which would you prefer to receive:- a shock of 50mA at 500v DC, or 100mA at 100v DC?

500v has the potential to do more damage to skin as it needs to overcome a lower skin resistance to pass through the body. You might have less chance of death due to the lower current of 50mA versus 100mA, but the burns will be deeper because your muscles will seize and the current will remain conducting.

I'd be making sure that my multimeter test-leads were in good condition and that the probe ends were short and well away from my fingers. 👍️

Exactly.

Thanks guys for all the advice. I think it's best to contact the installer as now both arrays are down. Things were going swimmingly for most of the past 12 months. Error pv-iso-pro-002 is now appearing which is a ground fault code for the positive.