Sanyo 190's and MX 60's in cold temps [RE-wrenches]

[Doug Pratt]

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On the other hand Dave... the MX60 doesn't blow up or let the smoke out of
components if the input voltage rises above 150 volts. It just shuts off and
waits. Those dark modules are going to warm up in the sun, the voltage is
going to drop, and when it drops under 150v, the MX60 will turn back on. 

This isn't quite so critical as string sizing to stay under 600v on grid-tie
inverters. (Which, as we all know by now, DO blow up, or at least
permanently stop working if they go over-voltage.)

Cheers,
Doug Pratt

-----Original Message-----
From: Jeffery Wolfe, Global Resource Options
[mailto:jeff at globalresourceoptions.com] 
Sent: Sunday, July 10, 2005 1:03 PM
To: RE-wrenches at topica.com
Subject: RE: Sanyo 190's and MX 60's in cold temps [RE-wrenches]


Dave,

Sounds like it's too high. Believing the NEC and Code, you'd need to
multiply that 135Voc by 1.25 = more than 150 V. In reality, there is a
cell temperature factor, and even if it's half of what the NEC says,
you're still over 150V. And the Sanyo panels are rated at -0%, +5%, so
you're not getting any relief by sub-nameplate performance, and will
probably be over nameplate on voltage.

If it was me, I would not series string them. It's just begging for
problems down the road. Some of the Outback engineers tend to
underestimate our climate up here. It means more strings, more fuses,
but less trips back to the site later!

Jeff
Jeffery D. Wolfe, P.E.
Global Resource Options, Inc., Solar Energy Solutions
601 Old River Road, Suite 3, White River Junction, VT 05001-9030
800-374-4494 x107 Toll Free     802-295-4415 x107 Phone
802-295-4417 Fax
Jeff at GlobalResourceOptions.com             www.GlobalResourceOptions.com

-----Original Message-----
From: David Palumbo, Independent Power & Light [mailto:ipl at sover.net] 
Sent: Sunday, July 10, 2005 3:11 PM
To: RE-wrenches at topica. com
Subject: Sanyo 190's and MX 60's in cold temps [RE-wrenches]


OutBack Power tells me to go ahead and series two Sanyo HIT 190's into
their MX60. They said to make sure it is a new model MX60 which is now
good for 150 VOC.

HIT 190 is 54.8V Max Power and 67.5 OCV, in series will be 109.6V Max
Power and 135 VOC

Site is in the North East Kingdom of Vermont, wicked cold (30 to 40
below occasionally), and will have reflection off of snow (top of pole
mount with array tilted at 85 degrees for winter). I have experienced
brightly sunny days where it has warmed all the way up to 10 below for
the highest daytime temp. Through in edge of cloud effect also.

My question is how much higher will the 135 VOC be pushed by the cold
temp.
and the snow reflectance?

Dave

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