Solar Basics3 min read1 views
How to Read a Solar Panel Datasheet in 2026: A Step-by-Step Guide
Wattage, Voc, Imp, temperature coefficients — decode every number on a modern panel spec sheet so you can compare brands like an engineer.
BySolarBazaar Team
Wattage, Voc, Imp, temperature coefficients — decode every number on a modern panel spec sheet so you can compare brands like an engineer.
## The numbers that actually matter
Ignore the marketing and look at four figures: rated power (Wp), module efficiency, the temperature coefficient of Pmax, and the open-circuit voltage (Voc). These decide real-world output and how many panels fit on your string.
## Reading it line by line
1. Rated power (Pmax): output at Standard Test Conditions — the headline wattage.
2. Efficiency: higher means more watts
per square metre, useful on tight roofs.
3. Temperature coefficient of Pmax: how much output drops as panels heat up — closer to zero is better in hot climates.
4. Voc and Vmp: string-sizing voltages your inverter must tolerate.
5. Tolerance and degradation: check the year-1 and year-25 warranty output.
## Comparing two panels fairly
Always compare at the same conditions and normalise by price-per-watt, not sticker price. A cheaper panel with a poor temperature coefficient can produce less energy over a Pakistani summer than a pricier one.
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