question

clint avatar image
clint asked

Off-Grid AC-Coupled Inverter Noise

I'm running a Multiplus-II GX in an off-grid system with AC coupled PV Enphase microinverters

I'm getting really bad flickering in the lights and humming from electronic devices under certain conditions

The issue happens when the PV inverters are under partial load (either cloudy conditions or output ramped down when bulk finished)

I've measured the current waveform coming out of the PV inverters and under these conditions the sine-wave gets very distorted with 2nd and 3rd harmonics

Has anyone else had experience with this? My thoughts are either trying to filter the PV inverter output or even just the light circuit as the flickering is the main issue for me

Multiplus-IIoffgrid
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2 Answers
Alexandra avatar image
Alexandra answered ·

@Clint

Not with enphase but Frounius does it too, and also the throttled down stages near sunset.

It is most likely the awkward range and interaction between the light control/power circuit as well. In many ways you also need bulbs that can handle dimming. Which not all leds can.

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clint avatar image clint commented ·
So it looks like i'm gonna have to replace the led bulbs with dimmable/dimmer compatible versions

What about sensitive electronics? What can i do to make it safe so it won't cause damage?

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jeanmarie avatar image
jeanmarie answered ·

Your issue @Clint sound quit similar to

https://community.victronenergy.com/questions/134143/unstable-microgrid-multiplus-ii-fronius.html

Unfortunately no other option than to wait and hope Fronius will soon releases an updated firmware.

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