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<div class=Section1>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'>All:</span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'> </span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'>I haven’t read the whole email but I
want to let everyone know that we have had terrible problems with the Xantrex
XW product. Part of the problem is that not everyone in tech support there is
equally knowledgeable about their XW line and they give inconsistent advice and
in some cases incorrect advice, Chalk it up to good intentions if you will but in
this case they paved the way to my private hell.</span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'> </span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'>We have had problems with the last two XW
systems we have installed and in each case the resolution was slow in coming. To
make things worse, Xantrex kept trying us to upload “new firmware”
as a panacea, which requires a piece of equipment that they charge the
installer for, and a laptop. The bottom line, it takes another week for the
stuff to come, another service call to upload the firmware and shipping the equipment
back to Xantrex (if you want you CC charge reversed).</span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'> </span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'>In one case the “new firmware”
was suggested for an XW that was manufactured two months earlier. So either
Xantrex has prematurely released the XW line (by over a year) or they’re
just guessing at our time and expense).</span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'> </span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'>I would like to nominate “I think some
new firmware should solve your problem” as one of the “top ten WAGs”
in the inverter tech support community. Does anyone want to share their
favorite?</span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'> </span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'>- Peter</span></font></p>
<div>
<p><font size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:
Arial;color:navy'>Peter T. Parrish, President<br>
California Solar Engineering, Inc.<br>
820 Cynthia Ave., Los Angeles, CA 90065<br>
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885<br>
CA Lic. 854779, NABCEP Cert. 031806-26<br>
peter.parrish@calsolareng.com</span></font><font size=2 color=blue face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:blue'> </span></font></p>
</div>
<div>
<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=2 width="100%" align=center tabindex=-1>
</span></font></div>
<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
re-wrenches-bounces@lists.re-wrenches.org
[mailto:re-wrenches-bounces@lists.re-wrenches.org] <b><span style='font-weight:
bold'>On Behalf Of </span></b>Mark Drummond<br>
<b><span style='font-weight:bold'>Sent:</span></b> Friday, April 24, 2009 12:40
PM<br>
<b><span style='font-weight:bold'>To:</span></b>
RE-wrenches@lists.re-wrenches.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> [RE-wrenches] Sunny
Island does not support using a transfer switching grid tie mode</span></font></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Hello Wrenches,</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>We’ve installed 2 sunny island systems, and were
planning to install three or four more, until we identified what I consider to
be a serious functional deficiency with the product. In commissioning the first
two inverters (different customers, but around the same time) I found that the
Sunnyboy inverters that were feeding the island would error out for AC
frequency tolerance exceeded when the inverter was in backup mode (no grid
signal present) and the batteries were mostly charged with charge current
coming in from the array. The SI frequency modulates to reduce battery charge
current and control battery voltage to absorption or float voltage – this
causes the SB to error, wait 5 minutes (because frequency returns to normal
once charging stops) then restart and error out again. This is particularly
problematic with a smallish battery bank and largish array as voltage can go
high fast.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>When I first reported this to SMA tech support it was
described as a communication problem. Apparently if the two inverters are
communicating, the SB is informed by the SI that it needs to operate in
off-grid mode and it should disregard the normal grid frequency tolerance. So
after a few return trips with new RS-485 cards and checking and double checking
the com wires to no avail, I was told that this was a firmware bug and that a
fix could be expected in some months, but with no solid time frame commitment. An
alternative was presented that the SB can be reprogrammed to run in off-grid
mode permanently, but since our systems have an inverter bypass transfer switch
in then we could not do that, because if that switch is switched then the SB
would be connected directly to the grid without the isolation of the SI, and
would take responsibility for anti-islanding. That’s clearly a no-no. </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>The transfer switch at the time was a requirement of the
utility (all loads must be able to be served directly by the utility if
necessary). This requirement was just removed by the PRC, but there are serious
design issues that are unacceptable in my eyes with removing the bypass. </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal style='margin-left:.5in;text-indent:-.25in'><font size=2
face=Arial><span style='font-size:10.0pt;font-family:Arial'>1)</span></font><font
size=1><span style='font-size:7.0pt'> </span></font><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'>If the sunny
island breaks, there is no option to power the critical loads directly from the
grid. We sell battery backup systems so that people have reliable power to
their critical loads. This would be clearly a better designed system if the
inverter could be bypassed. The other backup systems, like outback and Xantrex
(DC coupled) have easily integrateable and supported transfer switches for this
purpose – as they should. </span></font></p>
<p class=MsoNormal style='margin-left:.5in;text-indent:-.25in'><font size=2
face=Arial><span style='font-size:10.0pt;font-family:Arial'>2)</span></font><font
size=1><span style='font-size:7.0pt'> </span></font><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'>If the
inverter was out for repair (say it’s out of warranty, and has to be sent
for repair, not just quickly swapped out) the sunny boy would be down too as there
is no alternate path to the grid. With a bypass/transfer, the customer could
still be producing power and net metering while the backup system is down.</span></font></p>
<p class=MsoNormal style='margin-left:.5in;text-indent:-.25in'><font size=2
face=Arial><span style='font-size:10.0pt;font-family:Arial'>3)</span></font><font
size=1><span style='font-size:7.0pt'> </span></font><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'>Because the
SI is 120Vac, and the SBs are all 240 V, this means there must be a transformer,
or two inverters (and most people don’t need 10Kw of backup power). Some
customers would choose to forgo the automatic backup in favor of eliminating
the efficiency loss of the transformer in day to day grid-tie operation by
leaving the bypass switch activated except during a power outage, and manually
activate the backup system only when it’s needed. This is a less critical
issue, but having the option would be better.</span></font></p>
<p class=MsoNormal style='margin-left:.25in'><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Page 122 of the SI manual warns that if the batteries are full,
the frequency shifts and the inverter shuts down, but this is not quite true.
If the battery is small relative to the array size, the voltage will shoot up
fast, even when it is at a lower state of charge. It appears to be an all or
nothing charge – no tapering. I watched as one system continued to go
down In SOC until it got to the low eighties. I did not stick around to see how
low it would get. I reconnected the grid and promised the customer to try to
get to the bottom of it. 95% of the time during this test the SB was completely
disconnected. Because it waits 5 minutes to reconnect, it doesn’t even
work as well as the old series charge controllers (like the Trace C30A).</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>When we were designing the systems, we sent one-line
drawings to SMA to make sure it would work the way we wanted, and they were
given the thumbs up. This includes a more complex arrangement on a 3-phase
service that has not been installed yet and is on hold. We do not want to
install any more of them until this is resolved. We have customers with
battery-less systems that would like to retrofit. We’ve told many of our
customers that if they want to add battery backup later they can. I’m
anxious to see the fix.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Has anyone else seen this problem?</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Does anyone have a solution?</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Do any of you have systems that might have this problem, but
haven’t been put to the test?</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Am I missing something in the programming and tech support
just hasn’t caught it?</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Any help would be greatly appreciated</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Thanks,</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoAutoSig><font size=5 color=green face=Coronet><span
style='font-size:18.0pt;font-family:Coronet;color:green'>Mark Drummond</span></font></p>
<p class=MsoAutoSig><font size=3 face="Palatino Linotype"><span
style='font-size:12.0pt;font-family:"Palatino Linotype"'>Field Manager</span></font></p>
<p class=MsoAutoSig><font size=3 face="Palatino Linotype"><span
style='font-size:12.0pt;font-family:"Palatino Linotype"'>Positive Energy, Inc.</span></font></p>
<p class=MsoAutoSig><font size=2 face="Palatino Linotype"><span
style='font-size:10.0pt;font-family:"Palatino Linotype"'>NABCEP Certified PV
installer</span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
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