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Daily output of one panel
The rated output, scaled by the local sun and reduced by real world losses.
The Formula
daily kWh = (watts / 1000) x peak sun hours x (1 - losses)
The rated output, scaled by the local sun and reduced by real world losses.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| E | Daily output | kWh | The energy one panel makes per day. |
| W | Panel rating | watts | The nameplate watts of the panel. |
| H | Peak sun hours | hours | Equivalent hours of full sun per day. |
| losses | System losses | decimal | The fraction lost to heat, wiring, dirt and conversion. |
What Each Symbol Means
EkWh
Daily output
The energy one panel makes per day.
Wwatts
Panel rating
The nameplate watts of the panel.
Hhours
Peak sun hours
Equivalent hours of full sun per day.
lossesdecimal
System losses
The fraction lost to heat, wiring, dirt and conversion.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate solar panels needed page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate Solar Panels Needed, filed under Everyday Life. Every number the guide produces comes from substituting into this one line.