Step 3 - Select a "Nominal" DC side voltage that the design will be based on

The next step in the design process is to choose the operating DC side voltage of the system.

Most PV System components are built for Voltages in multiples of 12 except for batteries. Batteries are typically available for 2, 6 and 12 volts, which can be combined in series of parallel to meet PV Panel, Charge Controller and Inverter specifications. Batteries build for the Marine industry is available at 36 Volts but are not recommended for PV Systems. So, PV Panels, Charge Controllers, Invertors are built for "Nominal" system Voltages for 12, 24, 48 and higher in multiples of 12. In general, using a higher voltage system has the benefit of lower Current and consequently lower diameter of conducting wires. Recommended DC side system voltages are based on power rating of the system. For a system with less than 500 Watts power rating use 12 Volts, for 500-2000 Watts use 24 Volts and for more than 2000W use 48V and higher.

Select the DC side operating voltage before you proceed to the next step

• Step 0: Determine the Solar Hours of your location
• Step 1: Estimate the critical loads that need to be supported
• Step 2: Determine the days of Autonomy for the system
• Step 3: Select a "Nominal" DC side voltage that the design will be based on
• Step 4: Select the PV Panels to be used for the system
• Step 5: Select the Battery manufacturer and model to be used in System
• Step 6: Select an appropriate Charge controller
• Step 7: Select an appropriate Inverter
• Step 8: Calculate and select BOS components