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--- electrical:solar:overpaneling [2023/04/10 16:34]
frater_secessus [vs. battery bank]
+++ electrical:solar:overpaneling [2024/12/22 11:23] (current)
frater_secessus [vs. charge controller]
@@ Line 9: / Line 9: @@
 **Note:**  overpaneling is not //overvolting//, which would be exceeding the maximum input voltage of the charge controller.  Overvolting often results in damage to the controller; it can be caused by linking too many panels in series, or running too close to the voltage max in conditions that raise the panels' Voc.((http://www.cheaprvliving.com/forums/Thread-36-volt-solar-panel?pid=144154#pid144154))
 ===== vs. charge controller =====
+**TL;DR**:  overpaneling the controller means sizing MPPT for //actual// incoming solar power rather than //rated// panel wattage.
 {{ http://www.nacleanenergy.com/images/articles/NovemberDecember2014/Solar/advancedenergy_figure1.jpg?200}}
-**Overpaneling**, or having "too much" panel for the rating of your MPPT charge controller, can be desirable in some situations.  It is a **trade-off that biases the setup** to get more power out of normal and marginal conditions at the expense of the peak output during optimal conditions.((sun overhead, clear sky, low temps))
+**Overpaneling**, or having "too much" panel for the rating of your MPPT charge controller, can be desirable in some situations.  It is a **trade-off that biases the setup** to get more power out of normal and marginal conditions at the possible expense of the peak output during optimal conditions.((sun overhead, clear sky, low temps))
 >In car terms, the overpaneled system trades away some of the panels' top-end output for more low- and mid-range grunt. -- secessus
@@ Line 22: / Line 24: @@
+==== theory ====
-**Example:**  Consider the image to the right.((The image is that of a different PV-related configuration but it works for our purposes.)) The smaller/interior bell curve is the normally paneled configuration. \\
+Consider the image to the right.((The image is that of a different PV-related configuration but it works for our purposes.)) The smaller/interior bell curve is the normally paneled configuration. \\
 The larger/exterior curve is the overpaneled configuration. \\
 The striped area is the peak power "clipped" by the controller when the controller is overpaneled.  \\
@@ Line 38: / Line 41: @@
   * you spend time in partial shade
   * you want to use a smaller controller instead of jumping up to the next size.  Example, 43A max output and your choices are 40A or 60A controllers.
+==== example ====
+Let's say you want to adhere to Victron's 10-30% overpaneling approach.  Working backwards, their model appears to use 14.2v Vbatt as a constant.
+  * 500w / 14.2v = 35.2A.
+  * 35.2A on a 30A MPPT is    17.3% overpaneled:  ( (35.2 - 30) / 30 = 0.173)

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