User Tools

Site Tools


electrical:solar:charge_controller_setpoints

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
electrical:solar:charge_controller_setpoints [2020/01/13 10:51]
frater_secessus [Solar charge controller setpoints]
electrical:solar:charge_controller_setpoints [2023/07/21 23:15] (current)
frater_secessus [charging setpoints]
Line 1: Line 1:
 ====== Solar charge controller setpoints ====== ====== Solar charge controller setpoints ======
  
-[[electrical:solar:charge_controller|Solar charge controller]], [[electrical:converter|converter]], and [[electrical:12v:b2b|DC-DC]] charging behavior is guided by //setpoints//, or configured values stored internally.  They may or may not be configurable by the user. +[[electrical:solar:charge_controller|Solar charge controller]], [[electrical:converter|converter]], and [[electrical:12v:b2b|DC-DC]] charging behavior is guided by //setpoints//, which are settings stored in the controller.  They may or may not be configurable by the user. 
  
-The two most important setpoints are charging voltages:  Absorption voltage and Float voltage, discussed below. +The two most important setpoints for battery life and performance are charging voltages:  //Absorption voltage// and **Float voltage**, discussed below. 
  
  
 ===== charging setpoints ===== ===== charging setpoints =====
  
-[[electrical:12v:charging|Charging]] setpoints are configured in accordance with [[http://rvwiki.mousetrap.net/doku.php?id=electrical:solar:charge_controller_setpoints|the battery manufacturer's recommendations]].  These recommendations are published in manuals, spec sheets, corporate blogs, etc.  For example, [[https://www.trojanbattery.com/pdf/Trojan_QSG_AGM.pdf|Trojan's recommendations for charging their T-105 AGM batteries]] looks like this:  +[[electrical:12v:charging|Charging]] setpoints are configured in accordance with the **battery manufacturer's recommendations**.((Learn 'em, live 'em, love'em!))  These recommendations are published in manuals, spec sheets, corporate blogs, etc.  For example, [[https://www.trojanbattery.com/pdf/Trojan_QSG_AGM.pdf|Trojan's recommendations for charging their T-105 AGM batteries]] looks like this:  
  
 {{ :electrical:solar:trojan.png?400 |}} {{ :electrical:solar:trojan.png?400 |}}
  
  
-  * **Absorption voltage (Vabs)** - the voltage the battery bank is held at during [[electrical:12v:charging#absorption_stage|Absorption stage]].((sometimes confusingly called "boost" stage))  In this case the recommendation is 14.4v.+  * **Absorption voltage (Vabs)** - the voltage the battery bank is held at until [[electrical:12v:charging#absorption_stage|Absorption stage]]((sometimes confusingly called "boost" stage)) is //completed//In this case the recommendation is 14.4v.  //Completed// absorption means your lead batteries are fully charged.((the controller being in Float does //not// necessarily mean the batteries were fully charged; controllers can drop to Float too early due to bad design, incorrect battery chemistry switches, or incorrectly-configured setpoints.))    
   * **Float voltage (Vfloat)** - the voltage the battery bank is held at during [[electrical:12v:charging#float_stage|Float]].  In this case the recommendation is 13.5v.   * **Float voltage (Vfloat)** - the voltage the battery bank is held at during [[electrical:12v:charging#float_stage|Float]].  In this case the recommendation is 13.5v.
-  * **Temperature compensation** - how the voltage setpoints are adjusted for temperature.  While this is sometimes configurable, generally the compensation factor is close enough between manufacturers that it can be left at the default. +  * **Equalization voltage (Vequal)** - the voltage the battery bank is held at during [[electrical:12v:charging#equalization|Equalization]].  In this case the recommendation is 15v+. 
 +  * **Temperature compensation** - how the voltage setpoints are [[electrical:12v:charging#temperature_compensation|adjusted for temperature]].  While this is sometimes configurable, the compensation factor is close enough between manufacturers that it is often left at the default. 
   * **endAmps** - the amount of current (or percentage of capacity) accepted by the battery in late Absorption that indicates it's appropriate to Float.  In the lower-right of [[https://www.trojanbattery.com/pdf/Trojan_QSG_AGM.pdf|this graph]] Trojan shows it as [[electrical:12v:battery_capacity|C]]/200:((actually C/20/200, but C/200 here for simplicity))  Also see **absorption duration** below.   * **endAmps** - the amount of current (or percentage of capacity) accepted by the battery in late Absorption that indicates it's appropriate to Float.  In the lower-right of [[https://www.trojanbattery.com/pdf/Trojan_QSG_AGM.pdf|this graph]] Trojan shows it as [[electrical:12v:battery_capacity|C]]/200:((actually C/20/200, but C/200 here for simplicity))  Also see **absorption duration** below.
  
Line 26: Line 27:
 Less common setpoints: Less common setpoints:
   * **Absorption duration** - the amount of time Vabs will be held until dropping to Vfloat.  May be used instead of or in addition to any endAmps above.  endAmps is more precise but can be tricky to measure, as [[electrical:12v:loads|loads]] or [[electrical:12v:multipoint_charging|multiple controllers]] can obscure the true level of current being accepted by the battery.   * **Absorption duration** - the amount of time Vabs will be held until dropping to Vfloat.  May be used instead of or in addition to any endAmps above.  endAmps is more precise but can be tricky to measure, as [[electrical:12v:loads|loads]] or [[electrical:12v:multipoint_charging|multiple controllers]] can obscure the true level of current being accepted by the battery.
-  * **Absorption restart** - voltage (or duration) at which Absorption stage after failing to maintain Vfloat +  * **Absorption restart** - voltage (or duration) at which Absorption stage after failing to maintain Vfloat.  Sometimes called //rebulk// or //reboost//. 
- +  * **Equalization duration** - the amount of time the controller will hold Vequal. 
 +  * **Equalization frequency** - the number of days between equalization.  30 days is typical. 
 ===== load setpoints ===== ===== load setpoints =====
 Only present on controllers with LOAD outputs. Only present on controllers with LOAD outputs.
Line 37: Line 38:
 ===== non-setpoint settings ===== ===== non-setpoint settings =====
  
-  * **Maximum charge rate:**  While maximum charge rates normally are immaterial to solar charging((lead batteries accept what they want rather than taking what they are given)), Trojan specfies a maximum of [[electrical:12v:battery_capacity|C]]/5, or 1/5th of the battery's capacity in Ah.  +  * **Maximum charge rate:**  While maximum charge rates normally are immaterial to solar charging((lead batteries accept what they want rather than taking what they are given)), Trojan specfies a maximum of [[electrical:12v:battery_capacity|C]]/5, or 1/5th of the battery's capacity in Ah for this flooded example C/3 is a common max for AGM.  Lithium max charge is typically stated as C/2 for maximum life.   
-  * **Minimum charge rate:**  not stated in our example, but typical minimum charging values are ~C/10 for lead chemistries+  * **Minimum charge rate:**  not stated in our example, but typical minimum charging values are ~C/10 for flooded lead batteries, and ~C/5 for AGM. Lithium does not have a practical minimum rate so is not damaged by weak charging.
  
  
electrical/solar/charge_controller_setpoints.1578930695.txt.gz · Last modified: 2020/10/11 19:48 (external edit)