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electrical:12v:multipoint_charging

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electrical:12v:multipoint_charging [2018/08/26 07:03]
frater_secessus [why one source wins]
electrical:12v:multipoint_charging [2020/05/11 14:48]
frater_secessus [concurrent charging]
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 ===== concurrent charging ===== ===== concurrent charging =====
  
-So what happens when multiple chargers are running at the same time?  Nothing dramatic, as it turns out.  +So what happens when multiple chargers are running at the same time?  Nothing dramatic, as it turns out.((The only caveat, for advanced users, is if one of your controller uses end-amps to signal the end of Absorption, it may [[http://​forum.solar-electric.com/​discussion/​comment/​389634#​Comment_389634|get confused and drop out early]].))
  
-In general, **the charging source with the highest voltage will win**. ​ The only caveat is that if one of your controller uses end-amps to signal the end of Absorption, it may get confused and drop out early.((http://​forum.solar-electric.com/​discussion/​comment/​389634#​Comment_389634))+In general, **the charging source with the highest voltage will "win"**.
  
 ==== why one source wins ==== ==== why one source wins ====
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 The alternator is just a plain alternator and puts out 14.0v all the time. The alternator is just a plain alternator and puts out 14.0v all the time.
 The Morningstar charge controller is factory set to start Absorption at 14.4v.((i.e. Vabs == 14.4v)) The Morningstar charge controller is factory set to start Absorption at 14.4v.((i.e. Vabs == 14.4v))
-The Xantrex charge controller has been configured by you to start Absorption at 14.7v.((i.e. Vabs == 14.7v))+The Xantrex charge controller has been configured by you to start Absorption at 14.7v.((i.e. Vabs == 14.7v)) ((Normally the controllers would be set to the same voltage but we will make them different to illustrate how it works.)) 
  
 Let's charge that battery. ​ Here is the battery voltage along the way: Let's charge that battery. ​ Here is the battery voltage along the way:
  
-  * **12.2v** at daybreak, approximately 50% [[electrical:​depth_of_discharge|Depth of Discharge]]. ​ Charging is in the Bulk stage and **all three sources are charging**; the battery bank voltage is lower than what they all want to provide. ​ The alternator is contributing the most because it can produce the most current. +  * **12.2v** at daybreak, approximately 50% [[electrical:​depth_of_discharge|Depth of Discharge]]. ​ Charging is in the Bulk stage and **all three sources are contributing**; the battery bank voltage is lower than what they all want to provide. ​ The alternator is contributing the most because it can produce the most current ​and the panels aren't getting much light yet.  
-  * **13.9v** a few miles down the road. Voltage is climbing but all three sources are still charging.+  * **13.9v** a few miles down the road. Voltage is climbing but all three sources are still charging.  The sun is higher in the sky so the panels are making more power now
   * **14.1v** by the you get to a neighboring town.  **Alternator charging ceased at 14.0v**; it has plenty of current but no voltage "​pressure"​ to force that current into the battery. ​ Your battery bank is now being charging only by solar (the two separate controllers).   * **14.1v** by the you get to a neighboring town.  **Alternator charging ceased at 14.0v**; it has plenty of current but no voltage "​pressure"​ to force that current into the battery. ​ Your battery bank is now being charging only by solar (the two separate controllers).
-  * **14.6v** in the parking lot as you stop at an Oasis [[:water|water kiosk]]. ​ **The Morningstar stopped contributing at 14.4v**((Absorption is the stage where the controller provides as much current as it takes to hold Vabs, 14.4 in the Morningstar'​s case.  **It takes zero current to hold 14.4v when the bank is 14.6v**, so the Morningstar just sits there. ​ It might drop into Float.)) so we are down to just the Xantrex.  ​+  * **14.6v** in the parking lot as you stop at an Oasis [[water:drinking|water kiosk]]. ​ **The Morningstar stopped contributing at 14.4v**((Absorption is the stage where the controller provides as much current as it takes to hold Vabs, 14.4 in the Morningstar'​s case.  **It takes zero current to hold 14.4v when the bank is 14.6v**, so the Morningstar just sits there. ​ It might drop into Float.)) so we are down to just the Xantrex.  ​
   * **14.7v** on your way back to camp.  This is Absorption setpoint (Vabs) of the Xantrex, the highest setpoint of all three. ​ The Xantrex will continue the Absorption stage by itself until that stage is complete, then drop back to Float voltage (Vfloat).((where the Morningstar has probably been waiting, twiddling its thumbs))   * **14.7v** on your way back to camp.  This is Absorption setpoint (Vabs) of the Xantrex, the highest setpoint of all three. ​ The Xantrex will continue the Absorption stage by itself until that stage is complete, then drop back to Float voltage (Vfloat).((where the Morningstar has probably been waiting, twiddling its thumbs))
  
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 So how do we make them all charge all the time? So how do we make them all charge all the time?
  
-Barring heroic measures((exotic alternators/​regulators,​ DC-DC chargers)) the alternator is going to stop contributing at some point during Bulk charging. ​ That is ok, the alternator provided a ton of current while it was charging.+Barring heroic measures((exotic alternators/​regulators, ​[[electrical:​12v:​b2b|DC-DC chargers]])) the alternator is going to stop contributing at some point during Bulk charging. ​ That is ok, the alternator provided a ton of current while it was charging.
  
 But if you want to the charge controllers (and some [[electrical:​converter|converters]]) can be convinced to stay roughly in sync and keep charging together. ​ This is done by **configuring the Absorption and Float setpoints on the controllers to be the same**.((including Absorption termination setpoints like time or current)) ​ There will be short periods where one controller makes a change before the other, but for most of the time both will be contributing at the same time. But if you want to the charge controllers (and some [[electrical:​converter|converters]]) can be convinced to stay roughly in sync and keep charging together. ​ This is done by **configuring the Absorption and Float setpoints on the controllers to be the same**.((including Absorption termination setpoints like time or current)) ​ There will be short periods where one controller makes a change before the other, but for most of the time both will be contributing at the same time.
electrical/12v/multipoint_charging.txt · Last modified: 2020/05/11 14:48 by frater_secessus