Solar Panels under performing majorly!!

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Solar Panels under performing majorly!!

Postby chods1 » Mon Feb 12, 2018 4:38 pm

:( Hi everyone. I have a new solar array just installed [4 months]by Euro Solar claimed 6KW, 22 panels at 275 w ea. A Solax inverter model, x 1-5.0-T-N [AU]. According to my calculations this array should produce about 6kw under ideal conditions however my array [according to the inverter] is producing a max. of 2600-2700 w under ideal conditions ie no shade , midday etc.
I had a tech look at it he reckons that because of the distance to our pole [about 500 m] and the size of the cable [16mm diameter] there is too much pressure, as he put it, for the panels to produce more is this correct? Any thoughts?
Thanks in advance. :?
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Re: Solar Panels under performing majorly!!

Postby Gordon-Loomberah » Mon Feb 12, 2018 5:44 pm

I suspect one string of panels is not connected.


tech dude wrote: ... too much pressure, as he put it, for the panels to produce more

:lol:

If you can draw 5kW from the mains, and I find it difficult to image that you can't, then you should be able to export a similar amount back to the grid, assuming you don't run into voltage rise limits. However, you will generally always have some loads running at the house, so you would not expect 5kW to be exported, but rather, 5kW less any loads.

The inverter will clip its output at 5kW (I haven't looked up specs for that inverter, but perhaps (unlikely) it has an export limit set?), the extra panels wont allow it to exceed that, just let the inverter produce close to its rating for a bit longer in the middle of the day.

How is your array arranged - Tilt angle, direction etc?
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Re: Solar Panels under performing majorly!!

Postby chods1 » Mon Feb 12, 2018 6:38 pm

Thanks Gordon. The tech says that both strings are connected. I have 11 panels facing NW at about 22 degrees and 11 facing NE at 22 degrees.
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Re: Solar Panels under performing majorly!!

Postby Gordon-Loomberah » Mon Feb 12, 2018 6:57 pm

Can you verify that both strings are connected yourself? If you scroll through the menu I'd expect there should be displays of string 1 and string 2 voltage and current. Also grid voltage would be handy to know.

This could tell you too, if you have it:

Solax manual>>

WiFi
This inverter provides a WiFi port which can collect information from inverter including status, performance and updating information to monitoring website via connecting Pocket WiFi( purchase the product from supplier if needed)
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Re: Solar Panels under performing majorly!!

Postby chods1 » Mon Feb 12, 2018 7:14 pm

As the panels are in shadow now these are the readings,Net voltage 245.2,Current 1.5 amp, PV1 293.6v, PV2 331v, PV1 amps .4, PV2 amps .4, PV1 143w, PV2138w.
What do you think Gordon?
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Re: Solar Panels under performing majorly!!

Postby Gordon-Loomberah » Mon Feb 12, 2018 7:29 pm

hmm, I think you need to get the data when the panels are in full sun ;)

>>PV2 331v, PV2 amps .4, PV2138w.

331 * 0.4 = 132W, so I'm not sure where 2138W comes from.
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Re: Solar Panels under performing majorly!!

Postby chods1 » Mon Feb 12, 2018 7:32 pm

Sorry that's PV2 138w
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Re: Solar Panels under performing majorly!!

Postby Privatteer » Mon Feb 12, 2018 10:13 pm

I think I can see what the tech is pointing at, others will have to confirm.

500m is a long distance to have 16mm2. According to some rough calcs:
5000w over 500m at 255V = 8.4% volt drop or 21.4V
2700w over 500m at 255V = 4.5% volt drop or 11.6V

I can see the possibility that 245V(current line voltage) + 11.6V =256.6V volt rise while trying to export. Since most invertors shut down or limit at 255V I can see your local voltage at the house getting to that and it not being able to export any more power.
I'm assuming there is probably a tranformer at the end of the 500m run?


Since you have a split array NE/NW two readings on a sunny day, say 10:00am and 2:00pm would give us a better idea if the actual panels are working correctly and what the local voltage is doing.
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Re: Solar Panels under performing majorly!!

Postby Gordon-Loomberah » Tue Feb 13, 2018 6:04 am

I agree that 16mm^2 is rather small for such a long run, but 256V is well within the inverter's operating grid voltage range, but unless the inverter is set to limit output to 2700W, surely it would just disconnect when the voltage goes too high?
If output is limited at a certain voltage, then output would limit at export + household loads. If you turn on a say 2.4kW load, does the inverter still only produce 2700W?

According to p37 of the manual, you need to have a separate meter installed if a grid export limit is to be set.
I'm sure the tech would have mentioned if a low output limit had been set in the inverter.

If you have large loads at the house - electric stove, hot water, oven etc, with more than one operating at once, you may have a case for having the cable size increased, as there would be excessive voltage drop, due to undersized cable- cable that is not fit for purpose.
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Re: Solar Panels under performing majorly!!

Postby chods1 » Tue Feb 13, 2018 8:02 am

That's what I do not understand. The low amount of power produced by the array for use at the house. Never mind the export.
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