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sencha asked

PV YIELD ON SUNNY DAY GOES UP AND DOWN

Hello, being a newbie to the subject and the PV solar power as well, I would like an explaination to the following graph. It shows PV YIELDS (in Watts) during a sunny day with absolute clear sky. What I don't understand are those drops (see-saw pattern) in the graph. I'm using MultiPlus-II 48/3000/35-32 system with SmartSolar MPPT VE.Can 150/85 rev2 charger.

Thank you for any hints or explanations.

system-pv-yields-june-03.jpg

Multiplus-IIMPPT SmartSolar
system-pv-yields-june-03.jpg (80.7 KiB)
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2 Answers
mvas avatar image
mvas answered ·

Refrigerator turning on and off ?

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sencha avatar image sencha commented ·
Do AC Loads in the house (in the grid) affect PV Yelds levels?
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JohnC answered ·

Hi @Sencha

It's probably the mppt tracking, which it does every 10 minutes. And it's coinciding with the sample times of the GX/VRM. You can see it in detail in Victron Connect (Trends). It will also stop when the mppt reaches it's target charge state.

To get rid of it, try powering down the mppt for (say) 30 seconds, and the graph should smooth. It will still track, you just won't see it.

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sencha avatar image sencha commented ·
Thank you, @JohnC, for your explanation. It sounds reasonable. The only think that makes me still wonder is that we are 3 friends living relatively close to each other having the same system from the same company installed and --- THE SAME PATTERN IN THE PV_YELDS GRAPH. Could it be about a certain "software" setup that the company does? Or just a mere "coincidence"?
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JohnC avatar image JohnC ♦ sencha commented ·
@Sencha

In a simple system the mppts operate pretty much standalone. So I call coincidence. You can test it yourself, but using 10 min samples on VRM won't cut it. Try the per-second sampling of Connect, and you'll actually see the 'triple-dip' of the scan when it happens.

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