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electrical:solar:shading [2020/02/07 06:36] frater_secessus [examples] |
electrical:solar:shading [2020/03/17 16:15] frater_secessus [Partial shading] |
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+ | Words of Wisdom: | ||
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====== Partial shading ====== | ====== Partial shading ====== | ||
- | Partial shading can have surprisingly dramatic effects on panel output. The weirdest part is that //partial// shading can have more devastating effects on output than //full shading// like heavy overcast or evenly shaded forest canopies. | + | Partial shading can have surprisingly dramatic effects on [[electrical: |
- | + | ||
+ | ===== reminder: | ||
+ | **Before we begin:** solar panels are " | ||
+ | ces"; | ||
+ | Partial shading in this context means: | ||
- | It works this way: | + | * light is falling on the panel |
+ | * but not evenly on the panel -- it is different on some cells | ||
- | - partial shade causes //voltage differences// | + | To prevent power from rushing |
- | - electricity flows from higher-voltage areas to lower-voltage ones, so voltage differences would cause power to rush into the lower-voltage (shaded) cells | + | |
- | - overheating | + | |
- | To prevent damage panel manufacturer' | ||
===== panel configuration for partial shade ===== | ===== panel configuration for partial shade ===== | ||
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- | * With **PWM controllers, | + | * dedicated controllers for each panel is optimal |
+ | * [[electrical: | ||
+ | * With **PWM controllers, | ||
* With **MPPT controllers** and **low-ish voltage** serial panel configurations (where the total Vmp is <=2x battery bank voltage) it's close but **parallel will probably still yield more**. | * With **MPPT controllers** and **low-ish voltage** serial panel configurations (where the total Vmp is <=2x battery bank voltage) it's close but **parallel will probably still yield more**. | ||
- | * With **MPPT controllers** and **higher voltage** serial configs (say Vmp is >=3x bank voltage) we see **an increasing advantage of serial panel configs in partial shade**. This occurs because the MPPT has a broader range of voltages to sweep and can find power points | + | * With **MPPT controllers** and **higher voltage** serial configs (say Vmp is >=3x bank voltage) we see **an increasing advantage of serial panel configs in partial shade**. This occurs because the MPPT has a broader range of voltages to sweep and can find [[https:// |
===== examples ===== | ===== examples ===== |