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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 – powering customer’s 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’t get much sun Dec – 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’t 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’s 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 “darned computer stuff” and he’s not
wrong with that opinion. </div>
<div> </div>
<div>At another site, similar config but larger system with
dual XW’s that I upgraded to 2.04 firmware remotely few days
ago and now the two inverters are literally fighting each
other under generator charge – 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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