SCP50W12VA heavy-duty anodized aluminum frame provides strength and convenient mounting access. Cells are laminated between high transmissivity low-iron 3mm tempered glass and sheettedlar-polyester-tedlar (TPT) material by two sheets of ethylene Vinyl acetate (EVA). This protects against moisture penetrating into the module. Mono-Crystalline cells areup to 20% efficient and is said to have a service life of about 25 years.Output Power (peak): 50WMax Power Voltage (Vmp): 17.6vMax Power Current (Imp): 2.84AOpen Circuit Voltage (Voc): 21.6vShort Circuit Current (ISC): 3.07AWorking Temperature: -45C to +85CTolerance: +/- 5%Size: 640x661x35mmRecommended Controller: 12V-10A When using a solar panel to charge a batterya Solar Charge Controller is required and sold separately.