[RE-wrenches] strings of older solar panels
Allan Sindelar
allan at positiveenergysolar.com
Wed Nov 18 11:03:57 PST 2009
Lee,
Note also that the MSX series was known to have some defective modules. They
showed correct Voc and Isc but essentially a flat I/V curve slope, meaning
very weak output; that was a real headscratcher for installers. I had a set
of 12 from around 1994 with this behavior. Solarex never recalled this bad
series, but I heard about it from another old-timer. Solarex replaced all of
mine under warranty, but warranties back then were 10 or 12 years, so by now
expired. Of course, back then there was a Solarex. But they knew which
serial numbers were prone to be defective.
I would encourage you to test array output before putting any effort into
making it a GT system. If these are low output, push hard on BP(?) to cover
them as known to be defective.
Allan Sindelar
Allan at positiveenergysolar.com
NABCEP Certified Photovoltaic Installer
EE98J Journeyman Electrician
Positive Energy, Inc.
3201 Calle Marie
Santa Fe, New Mexico 87507
505 424-1112
www.PositiveEnergySolar.com <http://www.positiveenergysolar.com/>
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Brian
Teitelbaum
Sent: Wednesday, November 18, 2009 11:33 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] strings of older solar panels
Lee,
I also have an old spec sheet for the MSX60/64 that does not state the max
system voltage. It does, however, state that it passes a 2700VDC frame/cell
isolation test. I don't know if that is the required test for a 600VDC
rating or not.
If I remember correctly, they were not sold with bypass diodes installed, so
if you do use them in a system above 24V, be sure to add the diodes.
Brian Teitelbaum
AEE Solar
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Solar Plexus
Sent: Wednesday, November 18, 2009 9:33 AM
To: RE-wrenches at lists.re-wrenches.org
Subject: [RE-wrenches] strings of older solar panels
Hi Wrenches.
I have a customer with 32 of the Solarex MSX-64 solar panels an
a battery-based system. He wants to go batteryless inverter. So I am
looking at 2 strings of 16 in series. But the solar panel spec sheet
doesn't say anything about system voltage rating. Can I do this?
If one solar panel in the string is shaded, does it see the
full string voltage of around 280 volts? Is there something in the way new
panels are made that makes them more able to handle this voltage, or is it
just that they are now tested for it?
My guess is this request may be happenning a fair amount. Is
there a reason these panels are not listed on the California GoSolr website?
Lee Tavenner
Solar Plexus
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