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electrical:solar:panels [2022/02/13 15:38]
frater_secessus [Monocrystalline] |
electrical:solar:panels [2022/07/10 16:53]
frater_secessus [Panel voltage] |
| * semi-flexible so it can be applied to curved shapes | * semi-flexible so it can be applied to curved shapes |
| * least affected by high temps | * least affected by high temps |
| * least affected by shading | * least affected by shading due to cell construction |
| | * least affected by cloudy/hazy conditions, due to increased sensitivity at the blue end of the light spectrum((https://www.academia.edu/32974503/Investigating_the_Effect_of_Spectral_Variations_on_the_Performance_of_Monocrystalline_Polycrystalline_and_Amorphous_Silicon_Solar_Cells)),((overcast light is blue-shifted)) |
| * very light | * very light |
| * CON | * CON |
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| * **Nominal 12v panels** have 36 cells. They will generally have max power (Vmp) around 18v and open circuit (Voc) around 21v.((https://www.altestore.com/howto/solar-panels-pv-and-voltages-a98/)) These are commonly found on mobile and portable installations. | * **Nominal 12v panels** have 36 cells. They will generally have max power (Vmp) around 18v and open circuit (Voc) around 21v.((https://www.altestore.com/howto/solar-panels-pv-and-voltages-a98/)) These are commonly found on mobile and portable installations. \\ Note: there are some "12v" panels that actually have 40 cells.((nominal 13v?)) Example: [[https://amzn.to/3Pcrcsi|Renogy 200w "12v"]] panels, with Vmp of 22v and Voc 27v. The extra voltage cannot be harvested by PWM so MPPT is effectively required with these. |
| * **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 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. | * **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. |
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| 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]]. | 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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| ===== Efficiency ===== | ===== Efficiency ===== |
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| PV are generally rated by several criteria((http://www.kg4cyx.net/solar-panel-specifications-explained/)) | PV are generally rated by several criteria((http://www.kg4cyx.net/solar-panel-specifications-explained/)) |
| * **Power (W)**: 190 Watts. <- rated power in Watts under lab conditions. You can derive **price-per-watt** by dividing $/watts. | * **Power (W, or Pmax)**: 190 Watts. <- rated power in Watts under lab conditions. You can derive **price-per-watt** by dividing $/watts. |
| * **Open Circuit Voltage (Voc)**: 36.00 Voc <- Volts in full sun with no load. In practice you will likely not see Voc when hooked to the controller, but **all parts of your solar installation need to be able to cope with the theoretical Voc**. In serial arrays the Voc ratings are added. | * **Open Circuit Voltage (Voc)**: 36.00 Voc <- Volts in full sun with no load. In practice you will likely not see Voc when hooked to the controller, but **all parts of your solar installation need to be able to cope with the theoretical Voc**. In serial arrays the Voc ratings are added. |
| * **Short Circuit Current (Isc)**: 7.42 Isc <- Amps in full sun when shorted. Also theoretical, but **connectors and cables need to be sized to handle Isc**. | * **Short Circuit Current (Isc)**: 7.42 Isc <- Amps in full sun when shorted. Also theoretical, but **connectors and cables need to be sized to handle Isc**. |
| While NOCT may be useful for gauging normal harvests, STC is used for system component((like controllers)) sizing because the panels really can make STC power((or even more)) in some real world conditions. The system needs to be sized to deal with high-output situations, particularly overly high panel voltages. | While NOCT may be useful for gauging normal harvests, STC is used for system component((like controllers)) sizing because the panels really can make STC power((or even more)) in some real world conditions. The system needs to be sized to deal with high-output situations, particularly overly high panel voltages. |
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| | **PTC** ([[https://www.osti.gov/servlets/purl/93997-mpCvkV/webviewable/|PVUSA]] Test Conditions)((https://solarmazd.com/stc-ptc-noct-what-do-they-mean-and-how-to-use-them/)) is a rarer standard. |
| ===== Diodes ===== | ===== Diodes ===== |
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