Panel array not producing as expected

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leonb asked May 29, '21

Panel array not producing as expected

Hello All,

I installed a 3 phase system at a client with 3 x 5kVA Multi's, 1 x 20kWhr FreedomWon, and 30 x 370w panels, 2 x 250-100MPPT with VEdirect connection on Venus.

Roof is approx 10deg facing NNW, and both Lorentz data and PVGIS for that set of info has given me my design parameters. Problem is I am not getting near the expected deliverables, I am seeing approx 45% less than expected. Let me elaborate a little

1. The 1 MPPT mostly always leads the other, by a fair wack

2. Client's load is heavy, very heavy, so I dont think thats the problem, no reason for MPPT's/ panels to not deliver, strangely bell curves under advanced look rather good, but just not what it should be.

3. I am seeing max kw from panels as expected based on Lorentz/ PVGIS data, BUT NOT the kwhrs.

4. We initially thought shading was an issue, but all trees cleared now, but no noticable increase in yield from panels.

5. All fuses, voltages on strings checked in combiner box. Cant see a problem.

6. MPPT reset to factory defaults and reprogrammed

7. Venus updated.

What I have not checked is the BMS, and if that is not being restrictive, and also cleanlyness of panels, doubt this will make any difference, but other than that I am stumped??

Any advice maybe

Best Regards

MPPT SmartSolar solar sizing

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klim8skeptic ♦ commented · May 29, 2021 at 10:29 AM

" Let me elaborate a little "

Please do. As the designer, installer and the person who is responsible for your end work, you have fallen well short.

The first people you have contacted is the community of volunteers on the Victron Community webspace.

You have given no facts or figures, or even an location.

You expect some help. Cough up some details.

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Elimac commented · May 29, 2021 at 10:46 AM

Is this offgrid or ESS system?

Of course, if offgrid, this might be completely normal!! What is the SOC state values reached during each cycle?

Please add more information, VRM graphics of MPPT production + Load + SOC would be ideal.

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Modifications Space

Node Red Space

Answer 1 · 2021-05-30T17:13:50Z

Alexandra answered · May 30, 2021 at 05:13 PM

@LeonB

https://www.victronenergy.com/mppt-calculator

Once programmed the page at the bottom has a kwh forecast based on location. Maybe conpare the figures you were expecting with the possible forecast ones given at the bottom of the page.

Time of year, solar day atmospheric conditions have a huge effect on yeild. I know i had a surprise for our location when i saw the forcast yeild. Glad we panelled for the really poor months. We have run for two years and it has been on point.

Maybe also check the irradiance on your two sites, for the month as well. For us we have one good peak month, but it is 840 w/m² but panels are rated at 1000 w/m² in STC.

But as others have pointed out. We cannot help you more unless there is more info.

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