Should RV solar panels be wired in series or parallel? Neither arrangement is automatically best. The decision depends on the panels, roof layout, shade patterns, cable run, temperature range, and solar charge controller.
What changes in series
In a series string, panel voltages add while string current remains approximately the current of one matched panel. Higher voltage and lower current can reduce voltage drop and conductor requirements on the run to the controller.
The cold-weather open-circuit voltage of the full string must remain below the controller's maximum PV input voltage. Series strings can also be more affected when one panel is heavily shaded, depending on panel bypass-diode behavior.
What changes in parallel
In parallel, panel currents add while array voltage remains approximately the voltage of one matched panel. Parallel wiring may limit the effect of shade on one branch, but the higher combined current can require larger conductors, branch connectors, and additional overcurrent protection.
Mixed series-parallel arrays
Larger RV arrays often use matched series strings connected in parallel. Each string should use the same number and model of panels and see similar conditions. Combining electrically different panels can reduce performance or create unsafe operating limits.
Check these values before wiring
- Panel open-circuit voltage (Voc) and temperature coefficient
- Voltage and current at maximum power
- Panel short-circuit current
- Controller PV voltage, current, and power limits
- Expected coldest temperature
- Conductor ampacity and voltage drop
- Connector and branch-fusing requirements
Use the current panel and controller data sheets. Do not choose a layout from nominal wattage alone.
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