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electrical:solar:panel-bank_ratio [2020/06/24 22:29]
frater_secessus [1:1]
electrical:solar:panel-bank_ratio [2022/06/05 23:07] (current)
frater_secessus [1:1]
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 ===== 1:1 ===== ===== 1:1 =====
 //1:1// == 200W solar + 200Ah battery bank. //1:1// == 200W solar + 200Ah battery bank.
-This generally considered the minimum, though it will likely work out fine in [[electrical:solar:output|sunny areas]] with light [[electrical:12v:loads|loads]].  It may not be enough in the winter when the sun is low and daylight short. +This is generally considered the minimum, as it can work fine in [[electrical:solar:output|sunny areas]] with light [[electrical:12v:loads|loads]] and shallow [[electrical:depth_of_discharge|depths of discharge]].((10-20% DoD?))  It may not be enough with heavier use, or in the winter when the sun is low and daylight short.  [[electrical:solar:rationing|Power rationing]] may be necessary.
-[[electrical:solar:rationing|Power rationing]] may be necessary+
- +
-Working backwards, fully charging lead-chemistries by 1:1 solar means requires about 8.45hrs of Full Sun Equivalent on MPPT, and about 9.7hrs FSE with PWM. **There is nowhere in the United States that averages 8.45hrs of FSE year around**.  The highest is Honolulu with an average of 5.96hrs. The highest monthly average is Las Vegas in June (7.69hrs).+
  
 +[[https://mouse.mousetrap.net/blog/2020/07/02/the-problems-with-11-solar-charging/|Working backwards]], fully charging lead-chemistries from 50% [[electrical:depth_of_discharge|DoD]] by 1:1 solar requires  ~8.45hrs of [[electrical:solar:output#insolation_maps|Full Sun Equivalent]] on MPPT [[electrical:solar:charge_controller|controllers]], or ~9.7hrs FSE with PWM. **There is nowhere in the United States that averages 8.45hrs of FSE year around**.  The highest is Honolulu with an average of 5.96hrs. The highest monthly average is Las Vegas in June (7.69hrs).
  
 +Workarounds:
  
 +  * add [[electrical:12v:alt_and_solar|another source of charging]]
 +  * use a battery chemistry that charges more efficiently and doesn't mind [[electrical:12v:psoc|PSoC]] (like [[electrical:12v:deep_cycle_battery#lithium_chemistries|lithium]])
 +  * fully-charging lead becomes possible with attentive panel tilt, requiring only 5.5hrs on MPPT and 6.4hrs on PWM.
 +  * fully-charging lead becomes possible with shallower cycling, like 75%.  This is the equivalent of the 2:1 systems below. 
  
 ===== 2:1 overpaneling ===== ===== 2:1 overpaneling =====
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 This slightly [[electrical:solar:overpaneling|overpaneled]] configuration brings in extra power for heavier loads or for use in areas without much sun.  This slightly [[electrical:solar:overpaneling|overpaneled]] configuration brings in extra power for heavier loads or for use in areas without much sun. 
  
-Working backwards, successfully fully charging lead-chemisties by solar means only requires about 4.25hrs of Full Sun Equivalent on MPPT, and about 4.85hrs FSE with PWM. +Working backwards, successfully fully charging lead-chemistries by 2:1 solar requires about 4.25hrs of Full Sun Equivalent on MPPT, and about 4.85hrs FSE with PWM. 
  
 On average, this would work in Little Rock, San Francisco, Phoenix, Birmingham, Atlanta, New Orleans, Albuquerque, Tulsa, Las Vegas, San Antonio, Houston, Salt Lake City, and Casper Wyoming.  Winters will require power management. On average, this would work in Little Rock, San Francisco, Phoenix, Birmingham, Atlanta, New Orleans, Albuquerque, Tulsa, Las Vegas, San Antonio, Houston, Salt Lake City, and Casper Wyoming.  Winters will require power management.
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 'Dwellers in the Pacific Northwest(("Northwet")) may need a 3:1 ratio to meet basic needs. 'Dwellers in the Pacific Northwest(("Northwet")) may need a 3:1 ratio to meet basic needs.
  
-Working backwards, successfully fully charging lead-chemisties by solar means only requires about 2.83hrs of Full Sun Equivalent on MPPT, and about 3.25hrs FSE with PWM.+Working backwards, successfully fully charging lead-chemistries by 3:1 solar requires about 2.83hrs of Full Sun Equivalent on MPPT, and about 3.25hrs FSE with PWM.
  
-On average this this opens up everything but Canada and Anchorage AK. +On //average// this this opens up everything but Canada and Anchorage AK. 
 ===== 1:2 underpaneling ===== ===== 1:2 underpaneling =====
 //1:2// == 100W solar + 200Ah of battery.  //1:2// == 100W solar + 200Ah of battery. 
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 Different battery types have different charging requirements: Different battery types have different charging requirements:
  
-  * lithium - no minimum, charge at any rate up to the max+  * lithium - no minimum, charge at any rate((see [[electrical:12v:drop-in LiFePO4#an_approach_to_greater_longevity|this article]] on gentler charging for longevity)) up to the max
   * flooded lead-acid:  minimum [[electrical:12v:battery_capacity|C]]/10 (10A per 100ah of capacity)   * flooded lead-acid:  minimum [[electrical:12v:battery_capacity|C]]/10 (10A per 100ah of capacity)
     * minimum ratio with MPPT = 1.25w:1ah     * minimum ratio with MPPT = 1.25w:1ah
electrical/solar/panel-bank_ratio.1593052141.txt.gz · Last modified: 2020/10/11 19:48 (external edit)