Electrolux - Solar Energy

Voltage and Solar Panels

PV modules have three different voltage ratings that it’s handy to understand.

• Nominal Voltage : The nominal voltage of a panel could also be called the “conversational voltage.” When we talk about the voltage of the panels and the other components of the system, we’ll most often use the nominal voltage. Nominal voltage actually refers to the voltage of the battery that the module is best suited to charge; this is a leftover term from the days when solar panels were used only to charge batteries. The actual voltage output of the panel changes as lighting and temperature conditions change, so there’s never one specific voltage at which the panel operates. Nominal voltage allows us, at a glance, to make sure the panel is compatible with a given system.
• Voltage at Maximum Power or Vmp : This is the highest voltage the panel can produce while connected to a system and operating at peak efficiency.
• Open Circuit Voltage or Voc : This is the maximum voltage that the panel can produce when not connected to an electrical circuit or system. Voc can be measured with a meter directly contacting the panel’s terminals or the ends of its built-in cables.