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electrical:solar:nonessential [2020/01/13 11:22] frater_secessus [how much surplus current is there?] |
electrical:solar:nonessential [2020/01/13 11:38] frater_secessus [how much surplus current is there?] |
In practice, actual loads may be heavier in the daytime (as when working with power tools) or at night (as when watching movies or running a forced-air furnace). | In practice, actual loads may be heavier in the daytime (as when working with power tools) or at night (as when watching movies or running a forced-air furnace). |
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Due to the nature of battery charging there are better times and worse times to run non-essential loads. If done attentively (or automatically) **one can run electrical loads that do not affect the battery's | If loads are applied attentively (or automatically!) **one can run electrical loads that [[electrical:solar:offthepanel|do not affect]] the battery bank's |
[[electrical:depth_of_discharge|State of Charge]]** at all. This is especially true for Lead-Acid chemistries that do not take much current in [[electrical:12v:charging|Float or late Absorption stages]]. | [[electrical:depth_of_discharge|State of Charge]]** at all. Additionally, consuming loads at the right time can also increase the health and longevity of lead batteries.((by keeping them at 100% SoC more of the time)) |
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===== how much surplus current is there? ===== | ===== how much surplus current is there? ===== |
There will generally be more "surplus" power available when using MPPT charge controllers v. PWM,((http://forum.solar-electric.com/discussion/comment/372165#Comment_372165))((http://forum.solar-electric.com/discussion/comment/250746#Comment_250746)) though the difference is less dramatic during periods one would run opportunity loads (see [[electrical:solar:nonessential#when_to_run_opportunity_loads|below]]). Siphoning off power can actually **help PWM controllers run cooler** by reducing the ON-OFF switching activity that generates heat. | There will generally be more "surplus" power available when using MPPT charge controllers v. PWM,((http://forum.solar-electric.com/discussion/comment/372165#Comment_372165))((http://forum.solar-electric.com/discussion/comment/250746#Comment_250746)) though the difference is less dramatic during periods one would run opportunity loads (see [[electrical:solar:nonessential#when_to_run_opportunity_loads|below]]). Siphoning off power can actually **help PWM controllers run cooler** by reducing the ON-OFF switching activity that generates heat. |
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| [[electrical:solar:overpaneling|Overpaneled]] systems have even more excess power available. |
===== when to run opportunity loads ===== | ===== when to run opportunity loads ===== |
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**The best time to run non-essential loads is when there is surplus current** over what battery charging needs. This means **during Float, or after current has started dropping off in Absorption**. | **The best time to run non-essential loads is when there is surplus current** over what battery charging needs. This means **during Float, or after current has started dropping off in Absorption**. For [[electrical:12v:deep_cycle_battery#lithium_chemistries|LiFePO4]] there is excess power any time after the bank has reached the intended charge state. |
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Opportunity loads should not be applied during [[electrical:12v:charging|Bulk stage]] since Bulk, by definition, means the battery is taking all the available current.((assuming no charging limit has been configured in the [[electrical:solar:charge_controller|charge controller]])) | Opportunity loads should not be applied during [[electrical:12v:charging|Bulk stage]] since Bulk, by definition, means the battery is taking all the available current.((assuming no charging limit has been configured in the [[electrical:solar:charge_controller|charge controller]])) |
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For [[electrical:12v:deep_cycle_battery#lithium_chemistries|LiFePO4]] set the LVD to Vfloat; there is no actual Absorption stage _per se_ in fractional-C charging. We use these setpoints only because our traditional lead-acid controllers work that way. | |
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===== timing opportunity loads ===== | ===== timing opportunity loads ===== |