Glossary

Solar yield

Unit Wh/day

What is Solar yield?

The energy a solar system actually delivers — calculated from panel power, peak sun hours and a system efficiency covering controller, temperature, soiling and cables.

Yield = Wp × peak sun hours × efficiency

What matters about Solar yield in practice?

Peak sun hours are not daylight hours but the hours in which a panel would, in theory, deliver its full rated output — depending on region and season, between barely one and a good six per day.

For the design, what counts is not the good day but whether the battery bank bridges the poor ones. In winter, at most locations solar covers hardly more than the system's standby current.

How do you calculate solar yield?

Daily yield in Wh = panel power in Wp × sun hours × system factor. The system factor covers controller, temperature, soiling and cables and is roughly around 0.75. Example: 200 Wp × 4 sun hours × 0.75 = 600 Wh, about 50 Ah a day at 12 V.

What influences yield most?

  • Season and latitude: in a German winter it is often only about one sun hour a day.
  • Orientation: panels lying flat on roof or deck deliver well in summer and little in winter.
  • Shading: a mast, tree or roof unit can knock out a large part of the panel.

How much solar power do I need?

Divide daily consumption by sun hours and system factor. If you want to be self-sufficient in summer, calculate with summer values; if you travel all year round, you also need alternator or shore power. The solar calculator does the calculation.

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Still unclear?

We are happy to explain it for your specific case.

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