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--- electrical:solar:faq_mppt_series [2020/01/07 22:51]
frater_secessus created
+++ electrical:solar:faq_mppt_series [2020/10/11 19:48]
@@ Line 1: / Line 1: @@
-====== Is MPPT required when wiring panels in series? ======
-MPPT [[electrical:solar:charge_controller|controllers]] are not //required// for [[electrical:solar:series_vs_parallel|series panel wiring]]. Counterexamples:
-  - Imagine a 24v battery bank being PWM charged by two 12v panels in series, for example. The series configuration is not important, but the relationship between panel voltage and charging voltage is.
-  - Imagine a the 24v panel string above MPPT charging a 12v battery bank.  The MPPT controller dies and a backup  PWM controller is installed to keep power flowing.  PWM will run the panel string at Vbatt, making roughly 1/2  the peak power the MPPT could make.  If it were three 12v panels in series then PWM would make 1/3rd the peak power.  Note that during float with no additional loads there would be no practical difference.
-"MPPT required for series" is shorthand for "when [[electrical:12v:electrical_notation|Vmp]] greatly exceeds battery bank voltages then PWM is hamstrung and MPPT advantage is most compelling."
-The corollary to this is "when Vmp is close to battery voltage then MPPT advantage is thinnest and PWM may actually make more power."

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