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electrical:solar:charge_controller

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electrical:solar:charge_controller [2024/04/16 20:28]
frater_secessus [specs] 		electrical:solar:charge_controller [2024/07/01 22:22]
frater_secessus [sizing your charge controller]
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 Cautionary example:  [[https://www.youtube.com/watch?v=z5RtZe9AW2E|12W Unregulated Panel vs. 220Ah AGM Bank]] Cautionary example:  [[https://www.youtube.com/watch?v=z5RtZe9AW2E|12W Unregulated Panel vs. 220Ah AGM Bank]]
 +==== sensors ====
 +
 +To charge correctly the controller needs to know the precise voltage and temperature of the battery bank.  
 +In the best case scenario these measurements are done with an external **temp sensor** and **voltage sense**((not a typo, it's called voltage sense)) that plug into the controller or talk to the controller via bluetooth. 
 +
 +In the absence of external sensors the controller tries to use any internal sensors it might have.  The values will be inaccurate: 
 +
 +  * battery voltage will read [[electrical:12v:voltage_sag|falsely high during charging]], and
 +  * temperature will read falsely high because of the heat the controller generates from its own electronics
 +
 +With **lead-chemistry batteries** both conditions can cause [[electrical:12v:psoc|chronic undercharging]], a key cause of [[electrical:batterycide|premature battery failure]].  Many **LiFePO4 batteries** have their own [[opinion:frater_secessus:agm2lifepo4#wait_lfp_can_be_damaged_by_charging_in_cold_weather|low temperature charging cutoff]] but those that do not must rely on the charger to disconnect when battery temps are ~freezing.
 +
 +
 +
 +
 ===== specs ===== ===== specs =====
  
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 ===== sizing your charge controller ===== ===== sizing your charge controller =====
 As with [[electrical:inverter|inverters]], sizing the controller correctly will help system efficiency and save money.  An oversized CC will have unnecessarily high parasitic drains as it powers itself and will cost more.  An undersized CC will not be able to put all the rated solar wattage to use and will leave no room for expansion. As with [[electrical:inverter|inverters]], sizing the controller correctly will help system efficiency and save money.  An oversized CC will have unnecessarily high parasitic drains as it powers itself and will cost more.  An undersized CC will not be able to put all the rated solar wattage to use and will leave no room for expansion.
 +
 +
 For PWM controllers, the formula is something like (panel wattage / 13) * (1.2 oversize for safety) = charge controller amps.((https://www.altestore.com/howto/sizing-pwm-solar-charge-controllers-a91/))  For PWM controllers, the formula is something like (panel wattage / 13) * (1.2 oversize for safety) = charge controller amps.((https://www.altestore.com/howto/sizing-pwm-solar-charge-controllers-a91/)) 
 MPPT controllers have more leeway in sizing since they can [[electrical:solar:overpaneling|control the output of the panels]] independently of battery voltage.   MPPT controllers have more leeway in sizing since they can [[electrical:solar:overpaneling|control the output of the panels]] independently of battery voltage.  
electrical/solar/charge_controller.txt ยท Last modified: 2024/07/01 22:48 by frater_secessus

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