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<p class="MsoNormal" style="margin-bottom: 0.0001pt; line-height:
normal;"><big><big>Allen:<br>
<br>
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</big></big></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; line-height:
normal;"><big><big>I asked you about a generator since the future
addition on one might influence your selected solution. <br>
</big></big></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; line-height:
normal;"><big><big>The GenReady ATS does not include any
load-shedding control algorithm based on AC input voltage
(representing full load/overload sensing) that would have to
be left unused. <br>
</big></big></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; line-height:
normal;"><big><big>The ATS "sensing breaker" and the "XFER",
"BAT+, and "BAT-" leads are intended to be used by a
generator's controller board to sense a grid brownout,
overvoltage, or failure condition, apply its internal timing
algorithms, then activate the ATS. There are no "smarts" in
the GenReady panel's ATS - it's a "dumb" switch.<br>
</big></big></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; line-height:
normal;"><big><big>I have a Generac EcoGen propane generator with
a 2-wire start, and no internal controller. It has no internal
"smarts" and relies totally on the controller functionality
internal to the PV inverter.</big></big></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; line-height:
normal;"><big><big>I'm using the Generac GenReady panel at my home
installation as follows for backing up critical loads:</big></big></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; line-height:
normal;"><big><big>(A) The inverter output from my XW system feeds
the "Generator Supply" breaker on GenReady panel. <br>
</big></big></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; line-height:
normal;"><big><big>(B) The AC1 grid connection on the XW is
connected to the lowest 2-pole breaker position on the top
portion (non-protected) side of the GenReady panel.<br>
</big></big></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; line-height:
normal;"><big><big>(C) The EcoGen generator is connected to the
AC2 (generator) input on the XW.<br>
</big></big></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; line-height:
normal;"><big><big>(D) In the "normal" configuration (no grid
failure), the GenReady internal ATS (automatic transfer
switch) is already activated, and the XW inverter's output is
feeding local protected loads. XW PV production in excess of
local load and battery charging requirements is connected to
the upper portion of the GenReady panel, and is consumed by
the local non-protected loads, or sold back to the grid.<br>
</big></big></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; line-height:
normal;"><big><big>(E) With a grid failure, the GenReady ATS
position does not change, and the inverter continues to feed
the protected loads (non-protected loads are "dead"). The XW
inverter will start/stop the generator as needed to keep the
batteries charged.<br>
</big></big></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; line-height:
normal;"><big><big>(F) So what is the GenReady ATS used for? It is
not needed with a dedicated protected loads panel, but
provided two advantages in my situation:</big></big><br>
</p>
<blockquote><big><big></big></big>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; line-height:
normal;"><big><big>(1) I needed to upgrade my main service panel
anyway, so choosing a panel with an internal ATS made sense.
Plus, I could connect a generator for the protected loads
(non-PV solution).</big></big></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; line-height:
normal;"><big><big>(2) With a PV solution, I use the GenReady
ATS to manually bypass the inverter. It's easier to do that
to flip the four breakers in the Xantrex AC Interconnection
Panel. I haven't done this yet, but it should be possible to
have the XW inverter control the ATS to switch the protected
loads back to the inverter if a grid outage occurs while the
ATS is in the inverter bypass mode.<br>
</big></big></p>
</blockquote>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; line-height:
normal;"><big><big>I totally agree with you that having an option
to provide a critical loads battery backup for solar
installations is an underserved market, particularly in rural
areas with frequent grid outages and brownouts. <br>
</big></big></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; line-height:
normal;"><big><big>An integrated inverter/charger, in conjunction
with a natural gas and/or propane generator, feeding a
separate critical loads panel is a great solution to offer
customers desiring an "UPS-like" configuration for critical
loads. The battery bank sizing will be a cost tradeoff between
hours of autonomy of the battery bank, versus size/run-time
for the generator (if equipped).<br>
</big></big></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; line-height:
normal;"><big><big>Hope this helps!<br>
</big></big></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; line-height:
normal;"><big><big>Regards,<br>
<br>
Gary Willett, PE</big></big></p>
<big><big>Icarus Engineering / Solar Services LLC<br>
NABCEP Certified Solar PV Installer # 031310-246</big><br>
<br>
</big><font color="#000000"><span style="font-size: 10pt;"><br>
</span></font>On 5/14/2011 4:28 PM, Allan Sindelar wrote:
<blockquote cite="mid:4DCEF3E9.8090103@positiveenergysolar.com"
type="cite">
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
Gary,<br>
Thank you for the referral to this product; I didn't know it
existed. If you reread my original post, you'll see that there's
no generator involved; this is purely inverter- and battery-based.
At the link you provided, I was able to download a spec sheet, but
the spec sheet lacked some of the information to determine how
well this would work in an inverter-based situation. It appears
that this unit includes a load-shedding control algorithm based on
AC input voltage (representing full load/overload sensing) that
would have to be left unused. It's not clear to me that this could
be set up to work as simply as a shift-to-backup on the critical
loads section could be automatic and based solely on loss of grid
AC. Have you used this in a GTWB installation? ?If so, what can
you tell us?<br>
<br>
This unit retails around $350 and is based on a generator-based
application. I would think that a simple series of AC critical
load panels, that include a simple 30 or 60A 120/240 automatic
transfer switch function in order to switch critical loads from
utility source to inverter source, would be a product with a
ready, small but growing market. We have requests for
sophisticated grid-tie with backup systems, intended as
preparation for possible permanent loss of utility electricity. <br>
<br>
Allan<br>
<br>
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<font face="Times New Roman, Times, serif"><b>Allan Sindelar</b></font><br>
<small><a moz-do-not-send="true"
href="mailto:Allan@positiveenergysolar.com"><font
color="#000099" face="Times New Roman, Times, serif"><u>Allan@positiveenergysolar.com</u></font></a></small><font
face="Times New Roman, Times, serif"><br>
<span style="font-size: 10pt;">NABCEP Certified Photovoltaic
Installer<br>
NABCEP Certified Technical Sales Professional<br>
New Mexico EE98J Journeyman Electrician<br>
<b>Positive Energy, Inc.</b><br>
3201 Calle Marie<br>
Santa Fe, New Mexico 87507<br>
<b>505 424-1112</b><br>
<a moz-do-not-send="true"
href="http://www.positiveenergysolar.com/" target="_blank"><u>www.positiveenergysolar.com</u></a><o:p></o:p></span></font>
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