Series and parallel panel calculator with MPPT validation (Fronius and Victron)

Enter the panel data and string settings, and check whether it is Compatible with your Fronius inverter or Victron/SmartSolar charge controller: maximum cold-state voltage, minimum hot-start voltage and maximum MPPT current. Avoid the most costly mistake in photovoltaics: exceeding the voltage limit.

Panel

Configuration

The three rules of the string

1. The cold start voltage must never exceed the equipment’s maximum voltage. The voltage rises as the temperature falls: at -5 °C, a 49.5 V panel can output more than 53 V. Exceeding the maximum voltage (1000 V for Primo/Symo, 600 V for Primo and GEN24, 100/150/250 V for SmartSolar) will damage the equipment and invalidate the warranty.
2. Hot Vmp above the minimum voltage. In summer, the panel loses voltage; if the string falls below the minimum (or Vbat + 5 V in Victron), the device stops charging at midday.
3. Current within the MPPT. Each MPPT input has a maximum current rating; with current panels rated at 13–15 A, many MPPT controllers only accept one string per input.

Further help: Victron MPPT calculator, how to choose an MPPT controller y codes 307 and 309/313 at Fronius.