[RE-wrenches] Inverter output fluctuations

[Howie Michaelson]

Hi,
I was finally able to get to the site with the light pulsating issue. It
turns out it is that it directly corresponds to the AC coupled SolarEdge
HDwave 6kW inverter.  Moreover, the pulsating gets stronger with higher
output of the SolarEdge inverter (as more sun pouches more current through
the inverter). And the hum of the XW+ very noticeably fluctuates in direct
proportion to light fluxuations. It affects all the lights in the house,
regardless of manufacturer, wattage or age. I did not have an oscilloscope,
but looking at the Hz, it does sag very slightly to 59.9 when the SolarEdge
is producing, down from a rock solid 60 Hz when the SE is not producing.
The output voltage does not change at all.  The fluctuations in both the
lights and the inverter hum immediately stops when the SolarEdge production
is shut off. So it is clearly some interaction between the 2 inverters
causing this issue.

Has anyone dealt with this issue before? Does anyone have any suggestions
for dealing with this, short of replacing the SolarEdge with a Schneider
high voltage Charge Controller?
Thanks,
Howie

On Mon, Jul 3, 2023, 7:09 PM Dave Angelini Offgrid Solar via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> I think I would try eliminating things. Turn off the AC coupling for a few
> days and get results. Turn of DC solar and get results. Measure AC voltage
> with a scope or just observe voltage during the flicker. Are all of the
> lights flickering? Are they on dimmers?  Are there any loads failing that
> could be the source? Is the output with-in spec? Rock solid 60 HZ right.
>
> Do an AC bypass of XW with the genset and check for flicker symptoms.
>
> Are they on Insight? They really need it for you to monitor.  Are there
> any faults, warnings or events ? Check history.  There are a few settings
> in the old XW+ that could have been glitched by a surge or nearby lightning
> strike.
>
> XW+ could have a damaged FET. Open the unit and do a  visual.
> There would be a smell and transistor fragments on the bottom right side
> of the power bridge. 90% of XW failures have visual evidence.
>
> While you have it open, Check the DSP sensing and control board, both LEDs
> (light-emitting diodes) D24 and D25 are on.
>
> Last thing is a DC power down of the unit and the DC buss for 5 minutes.
> If that does not work, then a reset to factory values.
> This is off an old list I got from Support many years ago and combined
> with my findings over the years. Really rare for this kind of weirdness and
> why it would be getting worse without visual evidence.
>
> Good Luck Howie!
>
>
>
>
> *Dave Angelini Offgrid Solar
> "we go where powerlines don't"
> http://members.sti.net/offgridsolar/ <http://members.sti.net/offgridsolar/>
> e-mail  offgridsolar at sti.net <offgridsolar at sti.net>
> text 209 813 0060*
>
>
>
>
> On 2023-07-03 12:42 pm, Howie Michaelson via RE-wrenches wrote:
>
> Hi All,
> I upgraded an old clients' off-grid system about five years ago to a
> Schneider XW6848+ and 2 Blue Ion 2.0 cabinets (32kWh). When the batteries
> were moving toward full, if the charge rate was on the higher side via
> generator or solar (AC coupled w/SolarEdge 6kW and DC coupled with an FM
> 80), they would start to get pulsating lights similar to symptoms of other
> older inverters when using a generator for charging. The solution for this
> pulsation has usually been to kick back the AC charge amperage just enough
> so the pulsating calmed down to a tolerable inconsequential level.  And
> that worked in this case as well.
> However, a few weeks ago, the pulsating became more noticeable and has now
> become fairly intolerable.  To my knowledge, no settings changes we made
> within the previous year, and these clients would be loath to make any
> changes, so I doubt there were any. More puzzling is the pulsating has
> started to happen at seemingly random times not related to charging.  It
> happens at night or pre-dawn mornings without the generator, or during the
> afternoons with solar charging.  And it is getting progressively worse.
> Anyone have any thoughts on why that would start getting worse now?
> Howie
>
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