proper inverter [RE-wrenches]

[Darryl Thayer]

Hello
looking for some ideas or solutions.   Perhaps an
inverter recommendation.
I have a system not of my creation, that is composed
of 32  (12 volt) modules mounted tight to the standing
seam roof.  I have reason to believe the modules are
120 watt. Connections are under the modules arranged
in rows of 4 across and 8 rows high, tight together. 
The connections on the end of each row are brought to
junction boxes and then 100 feet to the inverter
location.  The conduit is large.  The installer has
changed his expertise and left the area and no owner’s
manual.  

My problem is they are connected in series and I
measured the open circuit voltage at over 648 volts on
a heavy overcast and cool day. .  My guess is on a
cold day this would exceed 720 Voc.  The owner wants
it fixed at low cost, just a new inverter and change
the wiring.  The roof is difficult to reach, being
high and at a 45 degree angle.  I can reach a splice
every 4 modules connected in series. Such that I can
create 84, 168, 336, 672 Voc by reconnecting into sub
arrays.  If my guess is correct the Vmp is 16.9 and my
sub arrays would be 68, 135, 270, 541 Vmp.     I have
worked mostly with Outbacks and Sunny Boys.  The 3840
watts seems to high for the Outback.  The voltage
range of 270 Vmp seems to low for the SB voltage
window when the modules get hot.  What
recommendations?
I know you that work with lots of inverters this seems
stupid.
Thanks you
Darryl


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