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<div class="moz-cite-prefix">Corey;<br>
<br>
Would you mind sharing what relay didn't work, and which ones did,
along with inverter output current? Since the relays will be
running for hours at inverter rated output, my thinking would be
to oversize the relay by at least a factor of three. I might try
Outback's relay/ breaker ( ROCB) if possible. <br>
<br>
Thanks again for sharing,<br>
<pre class="moz-signature" cols="72">R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760</pre>
On 7/31/2013 12:24 PM, Corey Shalanski wrote:<br>
</div>
<blockquote
cite="mid:CA+SmqZ2K8m7bJhg3F6-SN=_688iV1UU3h31ogVmYQZPWQzMKug@mail.gmail.com"
type="cite">
<div dir="ltr">Mac,
<div><br>
</div>
<div>We have installed about ten AC coupled Magnum systems over
the past year.<br>
<div class="gmail_extra"><br>
</div>
<div class="gmail_extra">Overcharge protection is accomplished
by frequency shift, but Magnum recommends an auxiliary form
of battery management. The cheapest way to do this is to
program the relay driver on the Magnum advanced remote
control (ARC) to open/close a solid state relay at specified
battery voltage setpoints - similar to what Kelly mentioned.
Unfortunately the "cheapest way" sometimes comes back to
haunt us in the form of unanticipated extra costs. We had
two customer callbacks indicating their inverter had
mysteriously shut down - site visit revealed a fried relay
in each case.. so I would recommend at least investing in a
good quality relay if you choose this route.</div>
<div class="gmail_extra"><br>
</div>
<div class="gmail_extra">One other thing we have learned is
that not all grid interactive inverters are compatible with
the Magnum inverters. Specifically Power One Aurora string
inverters cannot seem to synchronize in off-grid mode - we
have had to switch out Auroras on two projects because of
this. We have had no such synchronization issues with SMA
inverters so far.</div>
<div class="gmail_extra"><br>
</div>
<div class="gmail_extra">--</div>
<div class="gmail_extra">Corey Shalanski</div>
<div class="gmail_extra">Joule Energy</div>
<div class="gmail_extra">New Orleans, LA</div>
<div class="gmail_extra">
<br>
</div>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On Wed, Jul 31, 2013 Mac Lewis <<a
moz-do-not-send="true" href="mailto:maclewis1@gmail.com">maclewis1@gmail.com</a>> wrote:
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<br>
Here is a paper on AC coupling the magnum.<br>
<a moz-do-not-send="true"
href="http://www.wholesalesolar.com/pdf.folder/inverter%20pdf%20folder/MagnumACcoupling.pdf"
target="_blank">http://www.wholesalesolar.com/pdf.folder/inverter%20pdf%20folder/MagnumACcoupling.pdf</a><br>
<br>
The key is to connect the AC input terminals on the
Magnum to the main<br>
panel (or a panel closer to the utility feed) and then
feed the utility<br>
interactive inverter to a subpanel that is connected to
the AC output<br>
terminals on the Magnum. Under normal operation, the
Magnum passes the<br>
power through and the utility interactive inverter is
connected to the<br>
grid. If the grid goes down, the internal relays
isolate the Magnum and<br>
the critical load panel from the grid and the Magnum
starts to make a sine<br>
wave that the UI inverter will export power to.<br>
<br>
You have to keep the critical load panel amperage below
the pass through<br>
rating on the internal relays on the Magnum, and the
grid connected<br>
inverter needs to have a lower output than the Magnum (I
think by 10%).<br>
Also, I'm not sure if the diversion controller Magnum
has been working on<br>
is out yet or not.<br>
<br>
I've never done this, but I am about to. Any wrenches
have experience<br>
doing an AC coupled magnum?<br>
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