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electrical:solar:charge_controller [2019/09/02 23:53] frater_secessus [shunt] holding Vans all day |
electrical:solar:charge_controller [2019/09/28 17:23] frater_secessus [sizing your charge controller] |
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* during bulk stage and the early part of absorption stage when the battery can take in the most power | * during bulk stage and the early part of absorption stage when the battery can take in the most power | ||
+ | * anytime the system is fully loaded down (charging and/or loads) | ||
* when the battery is most depleted (ie lowest resting voltage). | * when the battery is most depleted (ie lowest resting voltage). | ||
- | | + | |
- | * PWM controllers can only run the panel at whatever voltage they are charging at right now. In our example that is 12.2v. | + | * PWM controllers can only run the panel at whatever voltage they are charging at right now. In our example that is 12.2v. |
- | * Nominal 12v panels usually have max power output (Vmp) around 17v.((https:// | + | * Nominal 12v panels usually have max power output (Vmp) around 17v.((https:// |
- | * when a typical 100w panel((Iop = 5.6A)) is run at 12.2v in lab conditions it puts out **~68.32W**. The same panel run at Vmp (~17v) would put out **100W**. | + | * when a typical 100w panel((Iop = 5.6A)) is run at 12.2v in lab conditions it puts out **~68.32W**. The same panel run at Vmp (~17v) would put out **100W**. |
* during times of greatest PV efficiency((i.e. highest voltage)) (clear, cold weather) | * during times of greatest PV efficiency((i.e. highest voltage)) (clear, cold weather) | ||
* during times of low irradience (low light levels due to low angle or overcast conditions)((this is a function of higher input voltages))((https:// | * during times of low irradience (low light levels due to low angle or overcast conditions)((this is a function of higher input voltages))((https:// | ||
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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! | ||
MPPT controllers also tend to consume more power to run themselves than PWM models due to additional processing and electronic components. | MPPT controllers also tend to consume more power to run themselves than PWM models due to additional processing and electronic components. | ||
+ | |||
**MPPT may be a better fit** when: | **MPPT may be a better fit** when: | ||
* battery banks are cycled deeply on a regular basis so more time is spent in Bulk | * battery banks are cycled deeply on a regular basis so more time is spent in Bulk | ||
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[[electrical: | [[electrical: | ||
===== sizing your charge controller ===== | ===== sizing your charge controller ===== | ||
- | 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 control the output of the panels independently of battery voltage. |