Allen,
If it's a backup system, the batteries aren't going to draw a significant
amount of current until the grid goes down. 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.
Jeffrey Quackenbush
________________________________
From: Allan Sindelar <[email protected]>
To: RE-wrenches <[email protected]>
Sent: Thursday, August 9, 2012 11:18 AM
Subject: [RE-wrenches] GTWB outage monitor question
Wrenches,
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?
Allan
--
Allan Sindelar
[email protected]
NABCEP Certified Photovoltaic Installer
NABCEP Certified Technical Sales Professional
New Mexico EE98J Journeyman Electrician
Founder and Chief Technology Officer
Positive Energy, Inc.
3209 Richards Lane (note new address)
Santa Fe, New Mexico 87507
505 424-1112
www.positiveenergysolar.com
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