Solar Efficiency & The Shading Problem
Why 10% shading can kill 90% of your power — and how to fix it.
The most common misconception in van life is that a 200W solar panel produces 200W of power. In reality, a single leaf falling on one corner of your panel can drop your output by 80%. This guide explains the engineering behind the "Shading Problem".
How Bypass Diodes Work
Most rigid panels are divided into 3 "strings" of cells. Each string has a bypass diode. If one string is shaded, the diode allows current to bypass it so the other two strings can still work.
Parallel Wiring
Lower voltage, higher current. If one panel is shaded, it doesn't affect the other panel at all. Best for vans with roof racks or fans that might shade a panel.
Series Wiring
Higher voltage, lower current. Starts charging earlier in the morning. However, if one panel is shaded, the output of BOTH panels drops to the level of the shaded one.
// THE SOLUTION"If you have space for two panels, wire them in parallel if you have roof obstructions. If you have a clean roof, series-parallel hybrid (2S2P) is the ultimate for efficiency."