<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><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 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> RE-wrenches <re-wrenches@lists.re-wrenches.org> <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>
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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>
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<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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