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 [email protected] 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: [email protected] [mailto:[email protected]] 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: [email protected] [mailto:[email protected]] On Behalf Of Solar Plexus Sent: Wednesday, November 18, 2009 9:33 AM To: [email protected] 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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