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jbakuwel avatar image
jbakuwel asked

Flickering lights in off grid with SMA PV inverters

Hi,

I have two customers complaining about flickering lights at certain times. I found this rather non-verbose :-) reference "Fronius has a special firmware available, on request, that fixes light flickering issues that occur on certain installations under certain circumstance".

One customer also has a DC coupled SmartSolar charge controller; the other one does not yet have that.

These customers have SMA PV inverters, not Fronius PV inverters. Does anyone know which "certain" installations and "certain" circumstances are referred to here so I can discuss it in sufficient detail with SMA?

Jan


MultiPlus Quattro Inverter Charger
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2 Answers
mblowes avatar image
mblowes answered ·

Could it be water pumps cycling?


I've just done an offgrid.. it happened to be 3 phase.. I was moving some load between circuits and lights started to flicker intermittently afterward.. Turns out I moved the fresh water pump to same phase as lights. Moved it to 3rd phase and problem solved.

Multi's could start pump no problem.. but there was this little flicker.. Not sure if there are other ways it could be solve... Pump is just a small 1hp 230V AC induction type.. driven from 2 Multi 3kVA in parallel on that phase.


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jbakuwel avatar image jbakuwel commented ·

Hi mblowes,

It's surely not pumps starting. I think it's quite normal to see a minor flicker once when a substantial load turns on.... here in NZ we even observe that in grid connected houses.


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Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

I had a little experience with this before and after it was resolved by the Fronius firmware fix.

It generally occurred during the threshold periods between production and non-production, or charging and not-charging.

For example, at the start and end of the day when the inverter was right on the edge of it's available voltage window, but still had very little power production.

Also when the battery was full and the PV inverter needed to ramp down to nothing, then slightly back up again, and then the Multi would switch from charging, to discharging and then back again.

Whatever was happening would only effect some appliances (mainly some brands of LED lights) and some installations (household wiring?). Whatever those details were, as far as my experience everything was resolved with the Fronius firmware update.

Taking my Victron hat off, I am only hypothesising now, (risky) but my anecdotal observations were that the Fronius added some small (seconds) additional delay between the conditions being right to start-up, and beginning actual production, to prevent the hysteresis condition.

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jbakuwel avatar image jbakuwel commented ·

Hi Guy,

Thanks for getting back to me. I haven't been able to get 100% clarity about the circumstances when this is happening but it surely is happening when the batteries are full (and the PV inverters are ramped down). The Multi is making a "repetitive humming sound" (as if it's asked to supply power, then stop, then start, then stop) with a frequency of a couple of Hz. The lights flicker with a higher frequency and the flickering of LED lights is quite a problem (headache material).


May I ask how Fronius was "prompted" to create this firmware that is only available on request? It would be great if SMA could be prompted in the same way (but I'm not holding my breath). Or ... would it be possible to get a bit more detail about this fix so I can see if one of the many Sunny Boy parameters might help?


Perhaps relevant is that - as far as I know - this does not happening with the combination Sunny Island (battery inverter) and Sunny Boy (PV inverter). We have one customer with that combination and there are no complaints.

thanks,

Jan


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