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--- electrical:solar:panel-bank_ratio [2020/06/25 02:30]
frater_secessus [3:1 overpaneling]
+++ electrical:solar:panel-bank_ratio [2023/10/22 14:45] (current)
frater_secessus [1:1]
@@ Line 4: / Line 4: @@
 ===== 1:1 =====
 //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. [[https://mouse.mousetrap.net/blog/2020/07/02/the-problems-with-11-solar-charging/|There is nowhere in the continental United States]] that has enough insolation to get the job done with a 1:1 ratio.
+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 =====
@@ Line 39: / Line 42: @@
 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)
     * minimum ratio with MPPT = 1.25w:1ah

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