<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div><span>Allan,</span></div><div><span><br></span></div><div><span>I was thinking more of a CT relay. Although you're right, if it's going to be on the battery cables, there would need to be some kind of programmable option to relay mechanism that would trigger only under a range of current values, not merely the presence of DC current. I'm sure there is something like that out there for industrial applications, but it would seem to be some exotic fauna. </span></div><div><span><br></span></div><div>On second thought, it would make more sense to use a CT relay on the AC input from the grid to the inverter. As long as the customer is pulling power from the grid, or supplying it, there will be current on that circuit, and no current when the grid goes out. You would have to supply power, then, to the relay and then run
another circuit to the alert load through the relay. I'm not sure exactly how the wiring for this system is set up, but that's an easier bar to clear. Near the BOS, you could mount a 125A sub-panel from the inverter AC protected loads output with 3 breakers: one feeding the load center in the house, one for the relay power supply and one for the alert load. Then you could run two #12 wires from the relay through the raceway that contains the main load center feeders to the alert load.</div><div><br></div><div>I found a company supplying AC and DC CT relays and switches on a cursory search on google:</div><div><br></div><div>http://www.automationdirect.com/adc/Overview/Catalog/Sensors_-z-_Encoders/Current_Sensors_(AC_-a-_DC)<br></div><div><br></div><div>Jeffrey Quackenbush</div><div><br></div> <div style="font-size: 12pt; font-family: 'times new roman', 'new york', times, serif; "> <div style="font-size: 12pt; font-family: 'times new roman', 'new york',
times, serif; "> <div dir="ltr"> <font size="2" face="Arial"> <hr size="1"> <b><span style="font-weight:bold;">From:</span></b> Allan Sindelar <allan@positiveenergysolar.com><br> <b><span style="font-weight: bold;">To:</span></b> JRQ <quackkcauq@yahoo.com> <br> <b><span style="font-weight: bold;">Sent:</span></b> Sunday, August 12, 2012 4:00 PM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [RE-wrenches] GTWB outage monitor question<br> </font> </div> <br>
<div id="yiv101478402">
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<div class="yiv101478402moz-cite-prefix">Jeff,<br>
Great in theory...but I'm missing a few details as to how to put
it into practice.<br>
<br>
Can you tell me where I might find a relay with a 175A contactor
capacity, with a rating of at least 65V DC and an AC coil? If I
understand you correctly, that's what you are describing. I would
be surprised if such a product exists. Then how would you set up a
circuit to close the relay when current exceeds a few amps DC?<br>
<br>
And yes, the batteries are with the rest of the BOS, away from the
home.<br>
<br>
Thanks, Allan<br>
<br>
<div class="yiv101478402moz-signature">
<title></title>
<font face="Times New Roman, Times, serif"><b>Allan Sindelar</b></font><br>
<small><a rel="nofollow" ymailto="mailto:Allan@positiveenergysolar.com" target="_blank" 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>
Founder and Chief Technology Officer<br>
<b>Positive Energy, Inc.</b><br>
3209 Richards Lane (note new address)<br>
Santa Fe, New Mexico 87507<br>
<b>505 424-1112</b><br>
<a rel="nofollow" target="_blank" href="http://www.positiveenergysolar.com/"><u>www.positiveenergysolar.com</u></a></span></font>
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On 8/12/2012 11:17 AM, JRQ wrote:<br>
</div>
<blockquote type="cite">
<div style="color: rgb(0, 0, 0); background-color: rgb(255, 255, 255); font-size: 12pt; font-family: 'times new roman', 'new york', times, serif; ">
<div><span>Allen,</span></div>
<div><br>
</div>
<div><span>If it's a backup system, the batteries aren't going
to draw a significant amount of current until the grid goes
down. </span>If you can find a DC relay that triggers after,
say, 2A or 3A, install it on the battery conductors. The relay
should come on, then, when the grid goes down, but not when
the battery bank is in float charge-mode. It will stay on for
sometime after the grid comes back up, but that won't
compromise its alerting function, and it could even be useful
to the customer to have a sense of the whole discharge-charge
cycle for his system. This is assuming that your batteries
aren't also remote from the home.</div>
<div><br>
</div>
<div>Jeffrey Quackenbush</div>
<div><br>
</div>
<div style="font-size: 12pt; font-family: times, serif; ">
<div style="font-size: 12pt; font-family: times, serif; ">
<div dir="ltr"> <font face="Arial" size="2">
<hr size="1"> <b><span style="font-weight:bold;">From:</span></b>
Allan Sindelar <a rel="nofollow" class="yiv101478402moz-txt-link-rfc2396E" ymailto="mailto:allan@positiveenergysolar.com" target="_blank" href="mailto:allan@positiveenergysolar.com"><allan@positiveenergysolar.com></a><br>
<b><span style="font-weight:bold;">To:</span></b>
RE-wrenches <a rel="nofollow" class="yiv101478402moz-txt-link-rfc2396E" ymailto="mailto:re-wrenches@lists.re-wrenches.org" target="_blank" href="mailto:re-wrenches@lists.re-wrenches.org"><re-wrenches@lists.re-wrenches.org></a> <br>
<b><span style="font-weight:bold;">Sent:</span></b>
Thursday, August 9, 2012 11:18 AM<br>
<b><span style="font-weight:bold;">Subject:</span></b>
[RE-wrenches] GTWB outage monitor question<br>
</font> </div>
<br>
<div id="yiv101478402">
<div> Wrenches,<br>
For a grid-tied-with-backup system that is still in the
design stage, we have a customer request for a signal to
let them know when an outage occurs and they are running
on backup power, so that they may turn off unnecessary
loads and "go into backup consciousness". The problem is
that the entire home would be on backup, with the GTWB
system tied into a meter and main disconnect location
away from the home, rather than the more typical main
panel/subpanel approach at the home. Any relay-based
alarm based on loss of grid AC would not likely trigger,
as the switchover is too quick. Any ideas for simple
solutions, please?<br>
Allan<br>
<div class="yiv101478402moz-signature">-- <br>
<title></title>
<font face="Times New Roman, Times, serif"><b>Allan
Sindelar</b></font><br>
<small><a rel="nofollow" ymailto="mailto:Allan@positiveenergysolar.com" target="_blank" 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>
Founder and Chief Technology Officer<br>
<b>Positive Energy, Inc.</b><br>
3209 Richards Lane (note new address)<br>
Santa Fe, New Mexico 87507<br>
<b>505 424-1112</b><br>
<a rel="nofollow" target="_blank" href="http://www.positiveenergysolar.com/"><u>www.positiveenergysolar.com</u></a></span></font>
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