This shows you the differences between two versions of the page.
Both sides previous revision Previous revision Next revision | Previous revision Next revision Both sides next revision | ||
electrical:solar:panels [2022/01/15 03:06] princess_fluffypants [Solar panels] |
electrical:solar:panels [2023/05/04 20:06] frater_secessus [Panel voltage] |
||
---|---|---|---|
Line 7: | Line 7: | ||
[[electrical: | [[electrical: | ||
- | **As a general rule, expect panels to put out 60% of their rating** under absolutely best-case scenarios. This can increase at high altitudes, or decrease with higher humidity. Tilting or angling the panels can help squeeze out a few more percent. | + | **As a general rule, expect panels to put out 60% of their rating** under absolutely best-case scenarios. |
There are several types of PV widely available on the market, and many more in research stages. | There are several types of PV widely available on the market, and many more in research stages. | ||
Line 25: | Line 25: | ||
* slightly better than poly in uniform low light | * slightly better than poly in uniform low light | ||
* theoretically greater longevity than poly, much better longevity than thin film | * theoretically greater longevity than poly, much better longevity than thin film | ||
- | * slightly higher [[electrical: | + | * slightly higher [[electrical: |
* slightly better performance in higher temps than poly, possibly due to higher Vmp | * slightly better performance in higher temps than poly, possibly due to higher Vmp | ||
* CON | * CON | ||
Line 78: | Line 78: | ||
* 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 |
+ | * least affected by cloudy/hazy conditions, due to increased sensitivity at the blue end of the light spectrum((https:// | ||
* very light | * very light | ||
* CON | * CON | ||
Line 110: | Line 111: | ||
- | ---- | + | ==== half-cut ==== |
+ | |||
+ | Some panels are "half-cut" which means the cells are cut in half and wired to make 2x as many cells. | ||
+ | |||
+ | {Secessus reminds us we should avoid [[electrical: | ||
Line 119: | Line 124: | ||
- | * **Nominal 12v panels** have 36 cells. | + | * **Nominal 12v panels** have 36 cells. |
* **Nominal 20v panels** have 60 cells. | * **Nominal 20v panels** have 60 cells. | ||
- | * **Nominal 24v panels** have 72 cells. | + | * **Nominal 24v panels** have 72 cells. |
+ | * even higher | ||
Line 129: | Line 135: | ||
higher voltage panels are more common on the used market, as people upgrade residential/ | higher voltage panels are more common on the used market, as people upgrade residential/ | ||
- | MPPT [[electrical: | + | MPPT [[electrical: |
Higher voltage panels can reduce wire costs; amps are cut in half for the same amount of wattage. | 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: | Panel voltage((more precisely, the relationship between panel voltage and battery voltage)) is an important factor when [[electrical: | ||
+ | |||
+ | |||
===== Efficiency ===== | ===== Efficiency ===== | ||
Line 146: | Line 154: | ||
> At zenith, sunlight provides an irradiance of just over 1 kilowatt per square meter at sea level. Of this energy, 527 watts is infrared radiation, **445 watts is visible light**, and 32 watts is ultraviolet radiation. -- [[https:// | > At zenith, sunlight provides an irradiance of just over 1 kilowatt per square meter at sea level. Of this energy, 527 watts is infrared radiation, **445 watts is visible light**, and 32 watts is ultraviolet radiation. -- [[https:// | ||
- | Mono panels can capture about 15-20% of this energy. | + | Mono panels can capture about 15-20% of this visible light energy. |
===== Specifications ===== | ===== Specifications ===== | ||
PV are generally rated by several criteria((http:// | PV are generally rated by several criteria((http:// | ||
- | * **Power (W)**: 190 Watts. | + | * **Power (W, or Pmax)**: 190 Watts. |
* **Open Circuit Voltage (Voc)**: | * **Open Circuit Voltage (Voc)**: | ||
* **Short Circuit Current (Isc)**: | * **Short Circuit Current (Isc)**: | ||
Line 176: | Line 184: | ||
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. | 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. | ||
+ | **PTC** ([[https:// | ||
===== Diodes ===== | ===== Diodes ===== | ||