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Wrenches,<br>
Please tell me if I'm overlooking something, in what appears to be a
design weakness:<br>
<br>
I would like to use an Outback Radian system for a standard GTBB
system. In order to take full advantage of the system's
capabilities, I have to use all of Outback's main components; in
this case the FM60 or FM80 charge controller. The problem is that
the most common (and lower-cost) modules today are 60-cell, meaning
20 Vnominal. Given the 150V DC hard maximum voltage limit of the
FM-series charge controller, in our cold climate I can only use
these 20V modules in 60 Vnominal series strings; that is, in
multiples of three modules. As the Radian is (wisely) offered in 48V
only, pairs of modules would provide too low a voltage, and series
strings of four modules would exceed 150 Voc in cold weather. <br>
<br>
The base Midnite Classic 150 will safely operate to 198 VDC in this
application, but it won't communicate with the Mate3.<br>
<br>
Is this a fundamental design limitation in the Radian system,
suggesting that Outback is due for a controller upgrade, or am I
missing something obvious? It appears that arrays and racks have to
be sized in ~720-watt sets of three-module series strings, which can
be problematic in some designs. In the design in question I would
like to use 16 240W modules on two 8-module pole-top racks (for
seasonal adjustability); nothing in sets of three meets the
customer's output and aesthetic needs. <br>
<br>
Any solutions would be welcome.<br>
Thank you,<br>
Allan<br>
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<font face="Times New Roman, Times, serif"><b>Allan Sindelar</b></font><br>
<small><a href="mailto:Allan@positiveenergysolar.com"><font
face="Times New Roman, Times, serif" color="#000099"><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 href="http://www.positiveenergysolar.com/" target="_blank"><u>www.positiveenergysolar.com</u></a><o:p></o:p></span></font>
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