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electrical:solar:charge_controller [2021/07/17 20:44] frater_secessus [Using LOAD output] added fitz quote |
electrical:solar:charge_controller [2022/04/30 17:03] frater_secessus [shunt] |
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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 [[# | Charge controllers are generally **rated by the amount of output they can provide**. This output is shared by charging circuits and [[# | ||
Controllers operate based on [[electrical: | Controllers operate based on [[electrical: | ||
- | ===== types of charge controllers ===== | + | ===== specs ===== |
+ | |||
+ | Regardless of type, controllers will have several specifications in common. | ||
+ | |||
+ | * **rating (or " | ||
+ | * **Maximum input voltage** - the highest voltage the controller should ever see from the solar array.((it is common to leave ~20% margin)) | ||
+ | * **12v/ | ||
+ | |||
+ | |||
+ | ===== 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:// | [[http:// | ||
Line 65: | Line 78: | ||
> 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:// | > 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:// | ||
+ | |||
+ | Also see [[https:// | ||
+ | |||
+ | > ....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, | ||
+ | |||
+ | ==== USB converters ==== | ||
+ | [[https:// | ||
+ | These aren't controllers in the normal sense, but there are [[https:// | ||
+ | |||
+ | If you only need 5v USB power up to 2.5A per port this may be a workable solution. | ||
==== DDCCC ==== | ==== DDCCC ==== | ||
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If more power is needed (and there is physical space) additional PV can be added to match the charging output of an MPPT charger, often at a lower cost. [There are no prizes for fanciest or most expensive charge controller! | If more power is needed (and there is physical space) additional PV can be added to match the charging output of an MPPT charger, often at a lower cost. [There are no prizes for fanciest or most expensive charge controller! | ||
- | PWM's limitations are reduced when [[electrical: | + | There are also edge cases where //PWM can actually make more power than MPPT//. An example of this might be low-Vmp poly [[electrical: |
- | + | ||
- | There are also edge cases((low altitude, high temperature, | + | |
**MPPT is effectively required** when: | **MPPT is effectively required** when: | ||
- | * using panels with nominal voltages higher than 12v ((more | + | * using panels with nominal voltages higher than 12v ((more |
* space available for panels is limited, as on a sailboat or small vehicle | * space available for panels is limited, as on a sailboat or small vehicle | ||
* daytime loads are hampered by [[electrical: | * daytime loads are hampered by [[electrical: | ||
* [[# | * [[# | ||
* making [[electrical: | * making [[electrical: | ||
- | We say " | + | |
Further reading: | Further reading: | ||
Line 116: | Line 138: | ||
As with [[electrical: | As with [[electrical: | ||
For PWM controllers, | For PWM controllers, | ||
- | MPPT controllers have more leeway in sizing since they can control the output of the panels independently of battery voltage. | + | MPPT controllers have more leeway in sizing since they can [[electrical: |
See also [[electrical: | See also [[electrical: | ||
===== overpaneling ===== | ===== overpaneling ===== | ||
this section [[electrical: | this section [[electrical: | ||
===== Using LOAD output ===== | ===== Using LOAD output ===== | ||
- | It is common for charge controllers to have a LOAD output for powering (or switching) loads. | + | |
- | Not all types of loads should be run from these terminals, though. Morningstar says: | + | It is common for charge controllers to have a LOAD output for powering (or switching) loads. |
+ | |||
+ | |||
+ | ==== historical use ==== | ||
+ | |||
+ | LOAD terminals were originally used to control nighttime lighting, like pathway or garden lights. | ||
+ | |||
+ | ==== present use ==== | ||
+ | |||
+ | In practice the LOAD terminals typically are either ignored((some well-respected controllers don't have them anymore)) or used as [[electrical: | ||
+ | |||
+ | One benefit to doing this is you can define a [[electrical: | ||
+ | |||
+ | ==== why loads aren't powered | ||
+ | |||
+ | |||
+ | > The load outputs take power from the battery | ||
+ | |||
+ | Some loads are inappropriate for the LOAD output. Morningstar says: | ||
> Heavily inductive or capacitive loads such as **pumps, motors, compressors, | > Heavily inductive or capacitive loads such as **pumps, motors, compressors, | ||
inverters** should not be wired to the controller’s Load terminals. In addition, loads exceeding the Load Current Rating of the controller should not be connected to the controller’s Load terminals.((http:// | inverters** should not be wired to the controller’s Load terminals. In addition, loads exceeding the Load Current Rating of the controller should not be connected to the controller’s Load terminals.((http:// | ||
+ | |||
elsewhere they say: | elsewhere they say: | ||
+ | |||
> Inductive loads can generate large voltage spikes that may damage the controller’s lightning protection devices.((http:// | > Inductive loads can generate large voltage spikes that may damage the controller’s lightning protection devices.((http:// | ||
although an exception is made for the SunSaver MPPT which " | although an exception is made for the SunSaver MPPT which " | ||
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Note: in wind and hydro power applications the output can be sequenced so that LOAD is activated only when batteries are fully charged. | Note: in wind and hydro power applications the output can be sequenced so that LOAD is activated only when batteries are fully charged. | ||
- | > 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:// | + | |
===== positive ground controllers ===== | ===== positive ground controllers ===== | ||
Some controllers are labeled or described as " | Some controllers are labeled or described as " |