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electrical:12v:eternal_absorption

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electrical:12v:eternal_absorption [2020/09/17 20:03]
frater_secessus [gotchas]
electrical:12v:eternal_absorption [2021/05/05 11:04] (current)
frater_secessus [gotchas]
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-Note:  this is for deep cycle lead chemistries only.!  Lithium chemistries should not be held at full voltage. +Note:  this is for deep cycle lead chemistries only!  Lithium batteries should not be held at full voltage. 
  
  
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   * solar conditions - not enough good sun long enough to finish Absorption   * solar conditions - not enough good sun long enough to finish Absorption
  
-===== workaround  =====+===== workarounds  ===== 
 + 
 +While you may not be able to increase the //actual// duration,((as when the controller setpoint is maxxed out)) you can achieve a similar effect with one or more of these techniques:  
 + 
 + 
 +  * if duration setpoint is maxxed then **set Vfloat == Vabs**.  Absorption duration will effectively be "until the sun goes down"
 +  * **charge at a lower current** (charging minimum).  While [[opinion:frater_secessus:charging_faster|overall charging will take about the same amount of time]], Bulk's share of that time will increase and [[electrical:12v:charging#absorption|Absorption will take somewhat less time]]. 
 +  * **Absorb at a higher((but still manufacturer-sanctioned)) voltage** (Vabs), this will decrease Absorption duration.  Keep a close watch on water levels for flooded batts, and also mind the max allowable voltage for AGM/Gel. 
 +  * **Float at a higher((but still manufacturer-sanctioned)) voltage** (Vfloat).   
 +  * [[electrical:12v:alt_and_solar|supplement]] solar charging with another charging source during Bulk, allowing more time for solar to finish absorption. 
 + 
 + 
 + 
 + 
 + 
 + 
 +Some controllers/chargers have a "restart Absorption" option allows one to override Float and get more time at Vabs.  Best use of this feature would be to look at the controller display a few minutes before the Absorption timer is due to expire.  If acceptance is good let it go.  If acceptance is too high give the bank another round of Absorption.  
 + 
 +If those approaches are insufficient, //Eternal Absorption// approach completely forgoes Float stage, forcing the controller to stay in Absorption by **setting Vfloat to Vabs**. This addresses the controller issues above.  It will not address the insolation problem on a given day, but extended Absorption will help reduce damage from previous days of poor harvest. 
  
-The Eternal Absorption approach completely forgoes Float stage, forcing the controller to stay in Absorption by **setting Vfloat to Vabs**. This addresses the controller issues above.  It will not address the insolation problem on a given day, but extended Absorption will help reduce damage from previous days of poor harvest.  
  
-Alternatively, see:  [[electrical:severe_battery_use#increasing_effective_absorption_duration|increasing effective Vabs duration through increased voltage]]. 
 ===== side benefits ===== ===== side benefits =====
  
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   * calcium-enhanced batteries (typically starter batteries and some hybrid "marine" batteries) can be damaged((positive grid corrosion)) by long periods of excess voltage.    The question is which is worse for them:  chronic undercharging or grid corrosion from higher voltage.  Pick your poison.   * calcium-enhanced batteries (typically starter batteries and some hybrid "marine" batteries) can be damaged((positive grid corrosion)) by long periods of excess voltage.    The question is which is worse for them:  chronic undercharging or grid corrosion from higher voltage.  Pick your poison.
  
 +For these reasons, it would be optimal to watch the bank's tail current ([[opinion:frater_secessus:endAmps|endAmps]]) to see when he bank is fully charged.  If this occurs shortly before sundown (an hour, for example) then it's nearly optimal.  If endAmps is reached hours before sundown you likely don't need Eternal Absorption anymore and can return to normal charging. 
 + 
  
  
electrical/12v/eternal_absorption.1600387398.txt.gz · Last modified: 2020/10/11 19:48 (external edit)