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electrical:solar:charge_controller [2023/09/10 13:50] frater_secessus [present use] |
electrical:solar:charge_controller [2024/02/16 23:32] frater_secessus [how to choose] added video |
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Regardless of type, controllers will have several specifications in common. | Regardless of type, controllers will have several specifications in common. | ||
- | * **rating (or " | + | * **rating (or " |
* **12v/ | * **12v/ | ||
* **Maximum input voltage** - the highest voltage the controller should //ever// see from the solar array.((it is common to leave ~20% margin)) | * **Maximum input voltage** - the highest voltage the controller should //ever// see from the solar array.((it is common to leave ~20% margin)) | ||
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[note: | [note: | ||
There are //DC-DC converting charge controllers// | There are //DC-DC converting charge controllers// | ||
+ | |||
+ | |||
+ | ==== boosting ==== | ||
+ | |||
+ | Most charge controllers that convert voltage do it by //bucking// (reducing) panel voltage down to the appropriate charging voltages.((normal PWM don't reduce/ | ||
+ | |||
+ | // | ||
==== how to choose ==== | ==== how to choose ==== | ||
**PWM is a reasonable default choice** in typical scenarios((12v house power, 12v panels)); they work well enough and are inexpensive. PWM controllers can cost half or a third of their MPPT workmates for any given rated output.((10A, | **PWM is a reasonable default choice** in typical scenarios((12v house power, 12v panels)); they work well enough and are inexpensive. PWM controllers can cost half or a third of their MPPT workmates for any given rated output.((10A, | ||
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**MPPT is effectively required** when: | **MPPT is effectively required** when: | ||
* when one needs to squeeze every watt out of the panel | * when one needs to squeeze every watt out of the panel | ||
- | * using panels with nominal voltages higher than the battery bank voltage, like 24v panels with a 12v bank. To be fair, [[http:// | + | * using panels with nominal voltages higher than the battery bank voltage, like 24v panels with a 12v bank. To be fair, [[http:// |
* 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: | ||
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See also [[electrical: | See also [[electrical: | ||
+ | |||
+ | ==== should I upgrade my PWM to MPPT? ==== | ||
+ | |||
+ | If the system has changed and now MPPT is required for one of the reason above, then yes. | ||
+ | |||
+ | But most people consider this switch to make "more power", | ||
+ | |||
+ | So the questions are: | ||
+ | |||
+ | - do you need more power than you are getting now? | ||
+ | - would +15% be enough to meet your needs | ||
+ | - if so, would you pay [whatever the MPPT costs] to get that +15%? | ||
+ | |||
+ | There is a saying in solar circles that " | ||
===== multiple charge controllers | ===== multiple charge controllers | ||
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==== present use ==== | ==== present use ==== | ||
- | In practice the LOAD terminals typically are either ignored((some well-respected controllers don't have them anymore)) or used as [[electrical: | + | In practice the LOAD terminals typically are either ignored((some well-respected controllers don't have them anymore)) or used as [[electrical: |
==== why loads aren't powered from LOAD terminals ==== | ==== why loads aren't powered from LOAD terminals ==== |