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electrical:solar:panels [2022/08/11 19:51]
frater_secessus [Portable] |
electrical:solar:panels [2023/07/12 11:17]
frater_secessus [Solar panels] |
| To avoid overcharging,((a bit of an oversimplification, admittedly)) a [[electrical:solar:charge controller|charge controller]] is placed between the PV and the battery bank. | To avoid overcharging,((a bit of an oversimplification, admittedly)) a [[electrical:solar:charge controller|charge controller]] is placed between the PV and the battery bank. |
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| [[electrical:solar:output|Many factors]] will affect output; and panels will rarely generate power equal to their laboratory rating. | [[electrical:solar:output|Many factors]] will affect output; and panels will rarely generate power equal to their laboratory rating. As a general rule, expect panels to put out much less than their rated wattage under normal conditions. |
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| **As a general rule, expect panels to put out 60% of their rating** under absolutely best-case scenarios. | |
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| There are several types of PV widely available on the market, and many more in research stages. PV are described by how each panel's cells are constructed. | There are several types of PV widely available on the market, and many more in research stages. PV are described by how each panel's cells are constructed. |
| * **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 22.6v and Voc 27v. The extra voltage //cannot be harvested by PWM// so MPPT is effectively required with these. | * **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 22.6v 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. |
| | * even higher cell counts (and voltages) can be present in very large panels, like >400w. |
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