SolarTown, 12/15/2010
Review of Schott 235W Solar Panel
If you want a good American-made module Schott's are a good choice and they'll earn their keep over the life of the module. You may puzzle over the American-made part of this review. The Poly 235s are engineered in Germany and manufactured in Albuquerque, New Mexico in an ISO 9001:2008 certified facility, thereby qualifying for made in America. You may be surprised to learn that Schott Solar has manufactured solar products since 1958. The Schott solar modules compete with low cost Asian modules by delivering more power on a PTC basis.
Appearance - The Schott Poly 235 is a polycrystalline, 60-cell module with a white back sheet and an anodized aluminum silver frame. As a polycrystalline panel it displays a faceted and slightly blue hue.
Electrical Data - The STC output of this panel is 235 watts at 1000watts/m2, AM1.5 and 25ºC. The PTC rating is 212.4 watts under PTC conditions (1000 watts/m2, 20ºC, wind speed = 1 meter/sec and 10 meters above ground). The PTC/STC ratio is 90.4%, in good standing as compared to to the other panels we sell at SolarTown. (Take a look at our comparison of solar panels.)
- Maximum Power Voltage (Vmp): 30.2V
- Maximum Power Current (Isc): 7.78A
- Open Circuit Voltage (Voc): 37.1V
- Short Circuit Current (Isc): 8.42A
Schott solar panels also carry a positive power tolerance of 4.99 watts, or 2%. These panels are also compatible with Enphase micro-inverters (M190 & D380).
The STC efficiency of the Schott 235W solar panel is 14.0%, and the PTC efficiency is 12.7%. This is slightly lower than some of the efficiencies of other panels that we carry at SolarTown, but still competitive at this wattage level. These panels are about an inch longer (66.34") and slightly narrower (39.09") than other solar panels in this range that we carry at SolarTown.
Qualification - Schott modules are UL1703 listed and are manufactured in an ISO 9001:2008 certified facility. All of Schott's modules undergo thermal cycling, damp heat, and load pressure tests to ensure reliability in the field. Manufacturing is also highly automated, ensuring consistent manufacturing quality. This solar module has a Class C Fire Safety Classification.
Warranty - Schott offers a strong warranty - 5 years for module materials and workmanship, and a 25-year linear power output warranty. Year 1 assures the modules deliver 97% of their minimum rated power and the modules will degrade no more than 0.7% per year for years two through twenty-five. This results in a module delivering more power over the life of the product - if you do the math on this you will find these modules still deliver over 81% of the rated power after 25 years.
Glass - Schott poly 235 watt solar module uses 4mm, low-iron tempered glass which is comparable to some other American-made modules and thicker than some Chinese-made modules.
Frame -Schott Modules pass a wind loading pressure test at 5400Pa. They are durable in both wind and snow.
Weight & dimensions - The Schott Poly 235 is 66.34" x 39.09" x 1.97" inches. (993mm x 1685mm x 50mm), 18.01 square feet (1.67 square meters) and 50.6lb (23Kg). Panels at this wattage are on average 17.3 sq. ft. and 43.8 lbs. These panels are significantly heavier than other panels at this wattage, which should not be a problem unless you are thinking of installing these panels on a flat roof or other roof where you have to make sure with your engineer that it can hold up under the additional weight.
Junction Box/Connector Type - Schott modules use Tyco SolarLok connectors, and the modules have 3 bypass diodes. Bypass diodes help panels produce energy even under shady conditions, and are commonly employed.
Cost & Value - These modules are a good competitor to foreign and domestic panels. They are slightly more expensive, but they have a strong power output warranty. We think that these modules will earn their keep.
Opinion/recommendation - The Schott 235s offer a competitive product and a good value. Buyers can benefit from the made-in-America qualification when hunting for incentives and feel confident that the modules will deliver their planned power over the life of the array.
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