300 W PERC solar panel with 60 cells. Voc 39.39 V · Isc 9.78 A · TcVoc -0.318%/°C.
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String Compatibility Calculator
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Panel Matcher
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How the Algorithm Works
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Voc
39.39 V
Vmpp
32.09 V
Isc
9.78 A
Impp
9.35 A
TcVoc
-0.318 %/°C
TcPmax
-0.427 %/°C
Pmax
300 W
Cells
60
The Viessmann Vitovolt 300 M300 PA is a 300 W solar panel. Finding a compatible replacement requires matching the original electrical characteristics — particularly Voc, Vmpp, Isc, and temperature coefficients — to ensure safe operation within the same string.
Use the form above to find panels that match these specifications. Then verify the replacement in the String Compatibility Calculator with your inverter.
The most critical specs to match are: cell count (must be exactly 60), Voc close to 39.39 V (within ±5%), and temperature coefficient TcVoc close to -0.318%/°C. If Voc differs significantly, the string voltage at extreme temperatures may shift outside the inverter's MPPT range. The replacement finder above pre-screens all candidates by these criteria.
A higher wattage panel usually has a higher Vmpp or Isc, which can affect string voltage and current. Small increases (up to 10–15%) are typically safe if the other electrical specs align. The replacement finder shows a compatibility score — 'Exact match' means the specs align closely. Always verify the replacement in the String Compatibility Calculator with your inverter before installation.
If the replacement has a significantly different Voc or Vmpp, the string voltage may shift outside the inverter's MPPT range, reducing energy production or causing faults. This effect is amplified at temperature extremes: at low temperatures, voltage rises by the TcVoc coefficient. The replacement finder automatically accounts for this — it scores candidates by how closely the electrical specs match the original Viessmann Vitovolt 300 M300 PA.