Two main reasons why solar panels are almost never connected in series only are:
- Vulnerability to Performance Drop from One Panel: In a series connection, the current is limited by the weakest panel in the string. If one panel is shaded, damaged, or underperforming, it reduces the current of the entire series string, significantly lowering overall system output and efficiency.
- High Voltage and Safety Limits: Connecting many panels in series increases the total voltage, which can exceed safe operating limits of inverters or system components, posing safety risks and potentially causing equipment damage. Voltage also varies with temperature, which can push voltage beyond inverter maximums in cold conditions.
Therefore, to optimize efficiency, safety, and reliability, solar installations typically combine series and parallel connections to balance voltage and current while minimizing the impact of shading or panel mismatch.
