Solar panels in series vs parallel: wiring explained

Updated October 2026

How you wire panels together decides the voltage and current the inverter or controller sees. Series adds voltage and keeps current the same. Parallel adds current and keeps voltage the same. Power, in watts, is the same either way.

Example: four panels of about 550 W

Each panel is 41 V and 13.4 A at its working point, which is about 549 W.

Which to use

• Series gives high voltage and low current, so you can use thinner cable and lose less on long runs. This suits MPPT controllers and grid-tied inverters, which accept high input voltage.
• Parallel keeps voltage low and current high, which suits low-voltage controllers and shaded roofs, because one shaded panel hurts only its own string. It needs thicker cable and fuses for each string.
• Series-parallel mixes the two to fit the input window of your equipment.

The limits you must check

• Total open-circuit voltage, times about 1.2 for cold mornings, must stay below the maximum input voltage of the inverter or controller.
• Total current must stay below its maximum input current.
• Connect only panels of the same type in one string.

Work on live panels is dangerous, so use a licensed installer for the final connection. Next step: read the MPPT vs PWM guide and use the calculator.