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electrical:solar:overpaneling [2019/02/01 20:08]
frater_secessus [vs. charge controller]
electrical:solar:overpaneling [2023/11/22 10:31] (current)
frater_secessus [vs. charge controller]
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 **Overpaneling** has two related meanings;  both refer to having more solar panel output than a system might otherwise require. **Overpaneling** has two related meanings;  both refer to having more solar panel output than a system might otherwise require.
  
-  * [[#vs._charge_controller|overpaneled charge controller]] - battery bank and charge controller are evenly matched;  panel nominal or actual output is  more than the controller's rating. +  * Most common meaning:  [[#vs._charge_controller|overpaneled charge controller]] - battery bank and charge controller are evenly matched;  panel nominal or actual output is  more than the MPPT controller's rating.  This is the most common meaning. Note:  PWM controllers should not be overpaneled as they have no way to limit incoming current to protect themselves.  
-  * [[#vs._battery_bank|overpaneled battery bank]] - solar panels and charge controller are evenly matched; both are oversized compared to battery bank.  This is the most common meaning.+  * Less common meaning:  [[#vs._battery_bank|overpaneled battery bank]] - solar panels and charge controller are evenly matched; both are oversized compared to battery bank.  
    
  
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 The overpaneled system's power output bell curve is //shifted upwards// and cut off by the controller when it reaches its limits.  This is known as clipping, trimming, or clamping due to the "flat top" appearance of the overpaneled output curve. The overpaneled system's power output bell curve is //shifted upwards// and cut off by the controller when it reaches its limits.  This is known as clipping, trimming, or clamping due to the "flat top" appearance of the overpaneled output curve.
  
-**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. \\ +With appropriate overpaneling the clipping is relatively minor.  Victron notes that: 
 + 
 +>> Generally total energy harvested from a 130% panel oversizing results in less than 1% annual energy loss. -- [[https://www.victronenergy.com/blog/2014/03/28/matching-victron-energy-solar-modules-to-the-new-mppt-charge-regulators/|source]] 
 + 
 + 
 +==== theory ==== 
 + 
 +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 larger/exterior curve is the overpaneled configuration. \\  
 The striped area is the peak power "clipped" by the controller when the controller is overpaneled.  \\  The striped area is the peak power "clipped" by the controller when the controller is overpaneled.  \\ 
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   * you spend time in partial shade   * 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.   * 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.
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 +==== 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.  
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 +  * 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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-Overpaneling the bank gets lead-acid batteries charged faster and keeps them charged longer than other approaches.  This minimizes [[electrical:depth_of_discharge#partial_state_of_charge|battery murdering partial state of charge conditions]] found in [[electrical:solar:overbanking|overbanking]].+Overpaneling the bank gets lead-acid batteries charged faster((faster/shorter Bulk charging stages -  Absorption duration will not be affected)) and keeps them charged longer than other approaches.  This minimizes [[electrical:depth_of_discharge#partial_state_of_charge|battery murdering partial state of charge conditions]] found in [[electrical:solar:overbanking|overbanking]].
  
  
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 Since the underbanked system has less capacity will reduce your actual [[electrical:solar:sizing#your_reserve_needs|reserve days of power]] to some extent.  But during daytime there is //some// solar power coming in and an overpaneled configuration will harvest relatively more power in sub-optimal conditions.  The smaller bank will get through Bulk and well into Absorption faster, too. This will help extend the //effective// reserve days of power. Since the underbanked system has less capacity will reduce your actual [[electrical:solar:sizing#your_reserve_needs|reserve days of power]] to some extent.  But during daytime there is //some// solar power coming in and an overpaneled configuration will harvest relatively more power in sub-optimal conditions.  The smaller bank will get through Bulk and well into Absorption faster, too. This will help extend the //effective// reserve days of power.
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 +Further reading:
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 +  * [[electrical:solar:slim_reserve|slim reserves]]
  
electrical/solar/overpaneling.1549069730.txt.gz · Last modified: 2020/10/11 19:48 (external edit)