Solar PV Hints, Tips & Troubleshooting

We are getting a 22 panel ground mount system installed in a couple of weeks configured as 2 strings. The panel array will be about 45m from the inverter following a gentle curve. I need to lay the conduit in a trench and am wondering about 50mm ESB ducting vs 4" (110mm) Wavin pipe. Wavin also do a 60mm duct similar to the ESB 50mm. My feeling is that with the 50/60mm ducts it should be easy enough to pull the wires through but installer has a preference (though not a requirement) for 4" Wavin. The latter requires multiple 6m pipes being joined together whereas the ducting will be continuous with no joints. My preference is for the ducting with no joints. Has anybody had any experience of pulling wires (5x 4mm2) through ducting over this distance? Also interested in opinions regarding the choice of 6mm2 rather than 4mm2 for the wires from the panels to the inverter.

We are getting a 22 panel ground mount system installed in a couple of weeks configured as 2 strings. The panel array will be about 45m from the inverter following a gentle curve.

hmmm, you might want to be a little careful there, or define in more detail what you mean by "gentle curve". Panels which are in a string, typically like to have the same light falling on each panel. If your string is on a curve you'll find that a panel at each end will be angled differently away from the sun. Depending on that difference, you (might) see problems. Couple of degrees would be find I think, but if it was 20-30 degree difference, dunno……

It's not something that's normally done, you may require optimizers, but easy enough to add later I guess if on the ground.

Apologies for my poor phrasing! As slave1 pointed out correctly, I actually meant the wires from the panel array to the inverter will follow a gentle curve to avoid obstacles. My feeling is that the 50mm conduit will work especially as the end of the run is in an open field where there is good access for pulling the wire (even gently with an ATV if necessary). But I do accept that 4" Wavin should be a bit easier to pull through. Another issue is that the installers normally use 4mm2 wire (2 pairs in my case) whereas I thought that 6mm2 was the usual default. I need to work out the losses over 45m for both.

A quick calculation using 6mm2 vs 4mm2 wires (panels to inverter) would suggest a voltage difference at the inverter of about 2.4V maximum for the different wire thicknesses. At a max power current of 13A this would mean a rate of loss per string of 13*2.4=31.2W or about 62W max for both strings. In general it would be less than this but how much less I don't know in order to estimate the kWh lost. If we assumed that on average the panels were operating for 8 hours per day at 50% of their peak, it would give a daily loss of 62*.5*8=248Wh (or 0.248kwh) per day. This is quite small so probably not worth fitting thicker wire?

That is true and probably the hardest part to guesstimate! (My formula P=IxV is the same as yours P=I^2xR). My fudge is what did I mean by 50% of peak and I took it to mean 50% reduction overall. I presume there is some data somewhere on actual performance in Ireland vs theoretical. In any event I am happy to go with the 4mm2!

Nobody really will ever have two strings from different manufacturers but with the same orientation connected to the same inverter, to compare.

You'd have to find a geek doing tests with an individual panel in their back garden with a micro-inverter and a WattMeter

I have panels and a 5kw dyness battery installed since October 2023. Everything seems to be working fine and I haven’t been taking much heed of it but I am noticing now that as the battery charge drops in the evening it gets to around 35-40% and then just bombs down to 18-20% within a 5 minute window on the solis app. Here is an example:

It is happening at different times but always when the soc drops to around 40%. Have I a dodgy battery?

The blue line is grid import but I think that kicks in because the battery seems to overshoot its minimum soc of 20% therefore triggering the grid charging to bring it back up to 20%. Green line is battery charge/discharge.

Edited to correct line colours

Im seeing that 80% to 100% jump at around 04.30 now too. Odd alright. But tell me this: If 101% is 6kWh and you have a 5kWh battery, what does the inverter think the capacity is?

I think that may be the mystery solved. It seems to jump from 80-100% when the eddi comes on to charge. I changed the maximum amps to charge the battery from 50A down to 25A on something I read here but I think it only now ever goes to 80%. I've reset the charging to the original setting and will see if that fixes the issue.

A nice ground-mount being shown in this RTE News article here too:

https://www.rte.ie/news/2025/0303/1499810-storm-eowyn-renewable-energy/

I'd like to think that these are also bifacials. I wonder how long white paint would last under those given that Sligo can be damp enough.

Hey all - I'm coming up to two years since getting our Solar PV system installed and in general, few complaints. However, the biggest one is a bit of a pain; for the past few months, the data shown in our Solarman Smart app has been truncated, and in fact the number of hours covered each day has reduced a time goes on. At this point, the app only shows data from 6.50am each morning (seemingly when the first rays of light hit the panels outside) until about 6.40pm (a while after the last bit of power is registered). The consumption for the rest of the day is not tracked or recorded in the app.

No clue is this a problem with the app or the logger; I previously reset the logger in the attic but nothing changed. I also contacted the company that installed the system, Swyft, but they haven't engaged with me at all.

Any thoughts on what could be wrong and how I can fix this?

Do you have a battery ? It sounds a mewhat like you do, as only hybrid inverters stay powered on 24 x 7 and only they have grid CT clamps which can track consumption.

So if you do have a battery, the inverter looks like it is now ignoring it, or the battery is dead