What is the difference between maximum MPPT voltage and open circuit voltage as described on a solar module data sheet and which parameter should be considered when sizing a system?

The MPPT voltage is the voltage at which the PV module can produce maximum power.

The open circuit voltage is the voltage measured across the terminals when there is no current flowing in the circuit (no load connected), this represents the highest voltage that the panel can ever have.

The open circuit voltage should be considered when designing a PV system as it has a direct effect on other devices connected to the same system.

Failure to consider the open circuit voltage may lead to damaged system equipment.