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electrical:solar:panel-bank_ratio [2017/10/01 10:46] frater_secessus created |
electrical:solar:panel-bank_ratio [2022/06/05 23:07] frater_secessus [1:1] |
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====== Panel:Bank ratio ====== | ====== Panel:Bank ratio ====== | ||
+ | A common rule of thumb for sizing batteries to solar power relates nominal panel output in Watts to bank capacity in Ah. It is not gospel. | ||
- | A common rule of thumb for sizing batteries to solar power relates nominal panel output in Watts to bank capacity | + | ===== 1:1 ===== |
+ | //1:1// == 200W solar + 200Ah battery | ||
+ | This is generally considered the minimum, as it can work fine in [[electrical: | ||
- | //1:1// == 200W((nominal)) | + | [[https://mouse.mousetrap.net/ |
- | //2:1// == 200W((nominal)) solar + 100Ah of battery. ([[electrical: | + | Workarounds: |
- | //1:2// would mean 100W((nominal)) solar + 200Ah of battery. (underpaneling or [[electrical: | + | * add [[electrical:12v: |
+ | * use a battery | ||
+ | * 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// == 200W solar + 100Ah of battery. | ||
+ | This slightly [[electrical: | ||
+ | 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, | ||
+ | |||
+ | ===== 3:1 overpaneling ===== | ||
+ | //3:1// == 300W solar + 100Ah of battery. | ||
+ | This significantly overpaneled configuration generally yields an excess of power, useful in rain, low winter sun, overcast conditions, etc. | ||
+ | ' | ||
+ | |||
+ | 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. | ||
+ | ===== 1:2 underpaneling ===== | ||
+ | //1:2// == 100W solar + 200Ah of battery. | ||
+ | Also known as [[electrical: | ||
+ | * solar charging is [[electrical: | ||
+ | * the battery bank is [[electrical: | ||
+ | Outside the above configurations, | ||
+ | |||
+ | ===== battery health ===== | ||
+ | |||
+ | Different battery types have different charging requirements: | ||
+ | |||
+ | * lithium - no minimum, charge at any rate((see [[electrical: | ||
+ | * flooded lead-acid: | ||
+ | * minimum ratio with MPPT = 1.25w:1ah | ||
+ | * minimum ratio with MPPT = 1.5w: | ||
+ | * AGM lead-acid: | ||
+ | * minimum ratio with MPPT = 2.5w:1ah | ||
+ | * minimum ratio with MPPT = 3w: | ||