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<p>That sounds like a generator problem. I've seen many gen sets
put out a horrible waveform under load, when battery charging.
The waveform, (if you have an O-scope) usually has a spike on the
front of the wave, and then the wave flattens significantly
after. The peak should be 169 v on a 120 vac RMS sinewave. I've
seen it as low as 135v on crappy generators that are over loaded.
THD is a great thing to check, but also check your peak voltage,
if you have a quick capture feature on your meter. <br>
</p>
<p>It also could be related to altitude, gen sets can perform badly
when they can't get enough air. You didn't mention gen set
model, or whether the frequency was a solid 60 hz. I've seen bad
things happen when the frequency got out of spec too. I'm
guessing a bad voltage regulator on the gen set. <br>
</p>
<p>Ray Walters<br>
Remote Solar<br>
</p>
<div class="moz-cite-prefix">On 4/25/2024 11:24 AM, Kevin Pegg via
RE-wrenches wrote:<br>
</div>
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<div>Hi Wrenches, </div>
<div> </div>
<div>Curious if anyone else has seen this issue. </div>
<div> </div>
<div>New XW Pro off-grid system installed Dec 2023. Pretty
standard config for us, XW Pro, 5 kW PV, 50 kWh UnigyII
battery, 8 kW high quality diesel generator. This system ran
fine all winter long \u2013 powering customer\u2019s big RV they were
living in while the house
is built, Shop, computer controlled outdoor wood boiler,
domestic loads + 3 person construction crew. Gen ran daily
on auto start as we don\u2019t get much sun Dec \u2013 Feb. No issues
reported. </div>
<div> </div>
<div>Couple weeks back I did a new system check up. All
performing well, happy client. Part of that service I
upgraded the XW firmware from 1.09 to 2.04, and insight from
1.16 to 1.18. Gave the system a quick check, ran gen. Lots
of sun now, batteries full
so didn\u2019t do a long generator test. Yes I set the region
codes for off-grid. </div>
<div> </div>
<div>A week later, while I was out of town and it was not so
sunny so gen running, client and their electrician called me
in a panic. Two smoke detectors had literally melted, as
well as several dimmable LED fixtures all failed.
Electrician replaced the burned
up devices, only to have the same thing repeat a few days
later. Talking with them it was only when the generator was
running there were issues. Told them to lock out gen and I
will get there when I can. </div>
<div> </div>
<div>Once back I attended site, fired up gen, and could hear
the inverter sounding terrible during gen charging. Lights
flickering bad, and I personally verified the smoke
detectors beeping and getting warm and the house smelled
like burned plastic. I hooked
up my power quality analyser and could see the THD gradually
building to over 36%. Gen voltage was at 125/250V a bit
high, so adjusted that, but no change. By reducing the
charge rate on the XW Pro to 50% was able to get the THD
down around 12% and less light
flicker. But it\u2019s still too high. Image attached shows THD
with gen on original programing, then at reduced charge
rate. </div>
<div> </div>
<div>Have now gone from a happy client to a pissed off client
threatening legal action for endangering their lives & a
bill from the electrician. Ugh. Having a hard time
explaining this to the client why a system previously
working fine went sideways so badly.
Old guy blames the \u201cdarned computer stuff\u201d and he\u2019s not
wrong with that opinion. </div>
<div> </div>
<div>At another site, similar config but larger system with
dual XW\u2019s that I upgraded to 2.04 firmware remotely few days
ago and now the two inverters are literally fighting each
other under generator charge \u2013 one load building to +6 kW
and one (minus)6 kW.
</div>
<div> </div>
<div>Sure makes me reluctant to upgrade firmware on systems
that are working fine. </div>
<div> </div>
<div>Any suggestions? </div>
<div> </div>
<div>Kevin </div>
<div> </div>
<div> </div>
<div><img
src="cid:DD1960AB0F60C14E984E9E8B7D9B7D74@CANPRD01.PROD.OUTLOOK.COM"
moz-do-not-send="true"> </div>
<div> </div>
<div> </div>
<div> </div>
<div> </div>
</span></font>
<br>
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