... 25 years at outdoor performance.Frequently Asked Questions1. What is the brand for this panel?HQ solar, ... manufacturer of this panel, OEM service is available, wholesales is welcome2. What kind of Solar Cells does it ... 16-18.9% for solar cells.6. What is the Nominal Voltage --18V, so it can charge 12V battery., ... series, if you not sure what to do, just mail us.7. What is the Warranty Period, How many ...