How the Panel Replacement Algorithm Works

Before scoring, every candidate panel must pass three hard filters. Panels that fail any filter are excluded entirely — they cannot safely replace the original.

Six electrical parameters are compared between the original and candidate panel. Each parameter has a tolerance range (ideal zone), a hard-exclude threshold (automatic rejection), and a scoring weight reflecting its importance for string safety.

Panels that pass pre-filters and hard-exclude thresholds are scored on a 0–100 scale. Higher scores indicate closer electrical match. The algorithm works in three steps:

The numerical score maps to four match quality levels. Each level indicates how closely the candidate matches the original panel.

Let's walk through scoring two candidates for replacing a 550 W panel. The numbers below are computed exactly as the algorithm does.

The replacement algorithm is a useful screening tool but not a complete engineering assessment. Keep these limitations in mind:

• The algorithm compares STC datasheet values only. Real-world performance depends on irradiance, temperature, shading, and degradation.
• Mechanical compatibility (dimensions, mounting, connectors) is not checked. Verify physical fit before ordering.
• String-level compatibility with your inverter is not verified. Always run the replacement through the String Compatibility Calculator.
• Degradation is not accounted for. A new replacement panel paired with aged panels may cause mismatch current.
• Warranty and certification requirements may restrict which replacement panels are acceptable for your installation.
• The database may not include every panel on the market. If your ideal replacement isn't listed, upload its datasheet.

• "Same wattage = safe replacement." Power rating alone says nothing about voltage compatibility. A 550 W panel with 72 cells has completely different Voc than a 550 W panel with 144 half-cells.
• "Same manufacturer = compatible." Different series from the same manufacturer can have very different electrical characteristics.
• "Higher wattage is always better." A higher-wattage replacement may push string voltage above inverter limits, especially in cold weather.
• "Current mismatch doesn't matter." In a series string, the panel with the lowest current limits the entire string's output. A significant Impp difference reduces overall production.
• "Temperature coefficients don't matter for replacement." Different TcVoc values change how the string voltage shifts with temperature, potentially exceeding inverter limits at extreme temperatures.