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--- electrical:solar:panels [2022/07/10 16:54]
frater_secessus [Panel voltage]
+++ electrical:solar:panels [2023/04/06 21:30]
frater_secessus [Panel voltage]
@@ Line 111: / Line 111: @@
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+==== half-cut ====
+Some panels are "half-cut" which means the cells are cut in half and wired to make 2x as many cells.   This can result in better harvest in some partial shade conditions with some increase in complexity and expense.
+{Secessus reminds us we should avoid [[electrical:solar:shading|shade]] in the first place}
@@ Line 123: / Line 127: @@
   * **Nominal 20v panels** have 60 cells.  They will generally have max power (Vmp) around 30v and open circuit (Voc) around 36v.((https://www.altestore.com/howto/solar-panels-pv-and-voltages-a98/))  These are commonly found in residential rooftop installations.
   * **Nominal 24v panels** have 72 cells.  They will generally have max power (Vmp) around 36v and open circuit (Voc) around 42v.((https://www.altestore.com/howto/solar-panels-pv-and-voltages-a98/))  These are commonly found in commercial or residential ground level installations.  Due to internal construction (actually 2 36-cell segments in parallel)((https://youtu.be/ofo1HQyGG8s?t=1m22s)) they can be more resistant to partial shading.
+  * even higher cell counts (and voltages) can be present in very large panels, like >400w.
@@ Line 130: / Line 135: @@
 higher voltage panels are more common on the used market, as people upgrade residential/commercial installations
-MPPT [[electrical:solar:charge_controller|controllers]] do a DC-DC downconversion that is quite efficient. If Vmp isn't required most will move PV voltage away from Vmp to prevent power from ever getting to the CC.
+MPPT [[electrical:solar:charge_controller|controllers]] do a DC-DC downconversion that is quite efficient. If Vmp isn't required they will move PV voltage away from Vmp to prevent power from ever getting to the CC.
 Higher voltage panels can reduce wire costs; amps are cut in half for the same amount of wattage.
-They more likely to stay above charging setpoints in poor insolation or high heat.
+They are more likely to stay above charging setpoints in poor insolation or high heat.
 Panel voltage((more precisely, the relationship between panel voltage and battery voltage)) is an important factor when [[electrical:solar:charge_controller#how_to_choose|selecting a solar charge controller]].

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