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electrical:solar:charge_controller [2021/10/04 21:09]
frater_secessus [DDCCC]
electrical:solar:charge_controller [2022/04/30 17:21]
frater_secessus [specs]
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 Charge controllers are generally **rated by the amount of output they can provide**. This output is shared by charging circuits and [[#using_load_output|LOAD circuits]].  For example, a 20A controller might be using 18A for charging and have 2A available for LOAD. Charge controllers are generally **rated by the amount of output they can provide**. This output is shared by charging circuits and [[#using_load_output|LOAD circuits]].  For example, a 20A controller might be using 18A for charging and have 2A available for LOAD.
 Controllers operate based on [[electrical:solar:charge_controller_setpoints|factory- or user-defined setpoints]] (values) stored internally. Controllers operate based on [[electrical:solar:charge_controller_setpoints|factory- or user-defined setpoints]] (values) stored internally.
-===== types of charge controllers =====+===== specs ===== 
 + 
 +Regardless of type, controllers will have several specifications in common.  
 + 
 +  * **rating (or "size")** - this is usually the maximum output the controller can produce (charging + loads).((for technical reasons with PWM this will also be the *input* current limit)) 
 +  * **12v/24v/48v** - this refers to the nominal voltage of the battery bank it will be charging.  
 +  * **Maximum input voltage** - the highest voltage the controller should //ever// see from the solar array.((it is common to leave ~20% margin))  NOTE: a 50v input max does //not// mean a PWM controller can make efficient use of mismatched panel/battery voltages; that requires MPPT.  See [[#how_to_choose|how to choose]] below. 
 + 
 + 
 + 
 +===== Types of charge controllers =====
 [note from frater secessus: PWM vs. MPPT debates can get overheated in forums and comments. It's your money and your build so do it the way that meets your needs.] [note from frater secessus: PWM vs. MPPT debates can get overheated in forums and comments. It's your money and your build so do it the way that meets your needs.]
 +
 +=== The quick and dirty === 
 +
 +**PWM** is a lot cheaper, but less gives less power (50-60% of panel input can be used). **MPPT** is more expensive, but gives more power (80-90% of panel input can be used)
 ==== PWM ==== ==== PWM ====
 [[http://amzn.to/2hcZaj2|{{ https://images-na.ssl-images-amazon.com/images/I/41pwJOriZHL._AC_US160_.jpg}}]]**PWM** (pulse width modulation) controllers charge by connecting panels to battery until a given voltage setpoint is reached.  When the desired setpoint is reached the controller switches current on/off to the battery in very fast cycles and in such a duration needed to keep voltage from rising.  This time slicing power delivery is called is pulse width modulation, or PWM.  Some heat will be generated by the switching. Counterintuitively, the PWM may be cooler the touch when it is running full open because there is no switching going on to limit voltage. [[http://amzn.to/2hcZaj2|{{ https://images-na.ssl-images-amazon.com/images/I/41pwJOriZHL._AC_US160_.jpg}}]]**PWM** (pulse width modulation) controllers charge by connecting panels to battery until a given voltage setpoint is reached.  When the desired setpoint is reached the controller switches current on/off to the battery in very fast cycles and in such a duration needed to keep voltage from rising.  This time slicing power delivery is called is pulse width modulation, or PWM.  Some heat will be generated by the switching. Counterintuitively, the PWM may be cooler the touch when it is running full open because there is no switching going on to limit voltage.
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 There are some considerations when [[electrical:solar:mppt design|designing a system around an MPPT controller]]. There are some considerations when [[electrical:solar:mppt design|designing a system around an MPPT controller]].
 ==== shunt  ==== ==== shunt  ====
 +
 +see article below
 +
 +
 +==== single-stage chargers ====
  
 [[http://amzn.to/2yQppTX|{{ https://images-na.ssl-images-amazon.com/images/I/41Gwyw0BT5L._AC_US160_.jpg}}]] [[http://amzn.to/2yQppTX|{{ https://images-na.ssl-images-amazon.com/images/I/41Gwyw0BT5L._AC_US160_.jpg}}]]
-In this usage, //shunt controllers// are single-stage chargers that hold the bank at a [[electrical:solar:charge_controller_setpoints|setpoint]] (Vdisconnect)((whether generally or exactly)) as long as sufficient solar harvest is present.  When the setpoint voltage is achieved the controller is turned off for some amount of time.((In a hydro or windpower scenario the power cannot be turned off and is diverted (shunted) instead to a diversion load like water heating, water pumping, etc.))+Single-stage chargers hold the bank at a [[electrical:solar:charge_controller_setpoints|setpoint]] (Vdisconnect)((whether generally or exactly)) as long as sufficient solar harvest is present.  When the setpoint voltage is achieved the controller current is turned off for some amount of time.((In a hydro or windpower scenario the power cannot be turned off and is diverted (shunted) instead to a diversion load like water heating, water pumping, etc.)) There are several different ways of turning off the current:
  
-Technical note:  //shunts// short out the panels to control ON/OFF charging.  //Series chargers// behave similarly but open-circuit the panels.   //PWM// is like a superfast series charger whose ON/OFF cycles are so fast that an average voltage can be held.((it actually does it by varying the width of the ON periodsresulting in a percentage of ON time))+  * PWM - open circuit the panels very rapidly (tens-to-thousands times a second)and for varying lengths of time to hold the voltage setpoint more precisely.  Same as PWM controllers above, but in this market range the modulation tends to be cruder/slower and there is only one charging voltage setpoint. 
 +  * shunt shorts the panels ON/OFF (charge-and-stop, less common)  
 +  * series - open circuits the panels ON/OFF (charge-and-stopless common)
  
 Simple versions use simple electronics((as with [[https://www.flexcharge.com|Flexcharge]])) or relays to turn charging on until Vdisconnect is reached, at which point charging is turned off off. If/when voltage falls to some lower voltage (Vreconnect) charging begins again.  This is sometimes called [[electrical:12v:charging#charge-and-stop|charge and stop charging]] or on/off charging.  Voltage tends to wander a bit as the charging stops and starts.  They are often used where extreme simplicity/robustness is required, or where more complex electronics might cause electrical interference.((as in a ham shack)) Simple versions use simple electronics((as with [[https://www.flexcharge.com|Flexcharge]])) or relays to turn charging on until Vdisconnect is reached, at which point charging is turned off off. If/when voltage falls to some lower voltage (Vreconnect) charging begins again.  This is sometimes called [[electrical:12v:charging#charge-and-stop|charge and stop charging]] or on/off charging.  Voltage tends to wander a bit as the charging stops and starts.  They are often used where extreme simplicity/robustness is required, or where more complex electronics might cause electrical interference.((as in a ham shack))
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 > If your charge controller only holds [absorption] voltage for an hour or two, that is likely not enough time. As long as [there is a load] and you cycle the battery daily, you could set float voltage to 14.8v [to match absorption] without worry. Only when you stop cycling the battery do you need to return float voltage to more regular 13.2v levels. Premature application of float voltage by automatic charging sources is a battery killer.((http://www.cheaprvliving.com/forums/Thread-Solar-or-Battery-Problem?pid=229883#pid229883)) > If your charge controller only holds [absorption] voltage for an hour or two, that is likely not enough time. As long as [there is a load] and you cycle the battery daily, you could set float voltage to 14.8v [to match absorption] without worry. Only when you stop cycling the battery do you need to return float voltage to more regular 13.2v levels. Premature application of float voltage by automatic charging sources is a battery killer.((http://www.cheaprvliving.com/forums/Thread-Solar-or-Battery-Problem?pid=229883#pid229883))
 +
 +Also see [[https://goughlui.com/2020/06/05/teardown-tested-generic-kw12x0-w88-solar-charge-controller-10-30a-versions/|this comprehensive teardown]] that assesses:
 +
 +> ....a rather inexpensive piece of equipment but it doesn’t do a terrible job of being a basic solar charge controller. On the whole, it behaves as one may expect – protecting the battery from excessive voltage and overdischarge, with an integrated dusk timer function and USB outputs...what do you expect for $10-20? Something that works is already a big surprise to me.
  
 ==== USB converters ==== ==== USB converters ====
-[[https://amzn.to/3msdCUU|{{ https://m.media-amazon.com/images/I/71EmsM+loWL._AC_SY200_.jpg?100}}]]  +[[https://amzn.to/3msdCUU|{{ https://m.media-amazon.com/images/I/71EmsM+loWL._AC_SY200_.jpg?50}}]]  
-These aren't controllers in the normal sense, but there are [[https://amzn.to/3msdCUUmodules]] that connect to your panel's MC4 connectors and output USB power.  +These aren't controllers in the normal sense, but there are [[https://amzn.to/3msdCUU|modules]] that connect to your panel's MC4 connectors and output USB power.  
  
 If you only need 5v USB power up to 2.5A per port this may be a workable solution.  If you only need 5v USB power up to 2.5A per port this may be a workable solution. 
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 this section [[electrical:solar:overpaneling|has been moved]]. this section [[electrical:solar:overpaneling|has been moved]].
 ===== Using LOAD output ===== ===== Using LOAD output =====
-It is common for charge controllers to have a LOAD output for powering (or switching) loads.  One benefit to doing this is you can define a [[electrical:12v:lvd|Low Voltage Disconnect]] (LVD) setpoint and Low Voltage Reconnect to protect the battery from excessive discharge: 
  
-> The load outputs take power from the battery terminals.... the only advantage in using the load terminals is displayed info and the ability to disconnect the load at programmable voltage levels. -- mikefitz((https://diysolarforum.com/threads/epever-solar-charge-controller-false-measurements-on-the-load.23995/post-283823))+It is common for charge controllers to have a LOAD output for powering (or switching) loads A common-and-understandable misperception is that it is there to run your loads Kinda.  
  
  
-Not all types of loads should be run from these terminals, though.  Morningstar says:+==== historical use ==== 
 + 
 +LOAD terminals were originally used to control nighttime lighting, like pathway or garden lights.  These are relatively small, resistive loads.  Power to the LOAD terminal could be associated with sun (or lack of sun) and/or battery voltage.  
 + 
 +==== present use ==== 
 + 
 +In practice the LOAD terminals typically are either ignored((some well-respected controllers don't have them anymore)) or used as [[electrical:12v:lvd|low voltage disconnects]] power relays (see below).   
 + 
 +One benefit to doing this is you can define a [[electrical:12v:lvd|Low Voltage Disconnect]] (LVD) setpoint and Low Voltage Reconnect to protect the battery from excessive discharge: 
 + 
 +==== why loads aren't powered from LOAD terminals ==== 
 + 
 + 
 +> The load outputs take power from the battery terminals.... the only advantage in using the load terminals is displayed info and the ability to disconnect the load at programmable voltage levels. -- mikefitz((https://diysolarforum.com/threads/epever-solar-charge-controller-false-measurements-on-the-load.23995/post-283823)) 
 + 
 +Some loads are inappropriate for the LOAD output.  Morningstar says:
  
 >  Heavily inductive or capacitive loads such as **pumps, motors, compressors, and  >  Heavily inductive or capacitive loads such as **pumps, motors, compressors, and 
electrical/solar/charge_controller.txt · Last modified: 2022/05/03 11:09 by frater_secessus