nick panaro
Member
what are three things that determine voltage in a solar system?
solar power
- Thread starter nick panaro
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- Lockport, IL
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- Retired Electrical Engineer
Please stop asking us to do your homework for you. Tell us what you think the answer is, and let us take it from there.
nick panaro
Member
amount of solar cells, amount of solar radiation, and size of conductors? could this be correct?
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
I actually don't know the answer to this one. I think your first two items seem to be reasonable. The third I would change from "size of conductors" to "size of collectors" (meaning the size of the solar cells).
gar
Senior Member
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- Ann Arbor, Michigan
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- EE
101117-2107 EST
rick:
Can you provide some supporting information related to this question. The use of the word "three" specifically must relate to some other information you have.
The word "system" really opens up the number of possibilities to many rather than just three.
In the whole system I would include --- sun, space debris, the moon, atmosphere, position of the earth, the solar cell, its orientation, whether it is a tracker, wiring, inverter, load after the inverter, and the power system voltage. If I probe into the inverter, then there are even more items to the system.
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rick:
Can you provide some supporting information related to this question. The use of the word "three" specifically must relate to some other information you have.
The word "system" really opens up the number of possibilities to many rather than just three.
In the whole system I would include --- sun, space debris, the moon, atmosphere, position of the earth, the solar cell, its orientation, whether it is a tracker, wiring, inverter, load after the inverter, and the power system voltage. If I probe into the inverter, then there are even more items to the system.
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Nope you only got 1 out of 3 right. I suspect you are trying to be a solar installer working on a LV license?
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
101117-2346 EST
nick:
What does the V-I characteristic curve or family of these look like for a solar panel?
At what point on this curve do you want to operate, and why?
What are some advantages of a mini-inverter, one for each solar panel, vs a single inverter for a whole array of panels?
What happens if you open circuit the load on a solar panel?
Is the internal impedance of a solar panel a constant?
How do any of these questions relate to your question's three items?
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nick:
What does the V-I characteristic curve or family of these look like for a solar panel?
At what point on this curve do you want to operate, and why?
What are some advantages of a mini-inverter, one for each solar panel, vs a single inverter for a whole array of panels?
What happens if you open circuit the load on a solar panel?
Is the internal impedance of a solar panel a constant?
How do any of these questions relate to your question's three items?
.
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
And how is it that "solar radiation" (i.e., how much sunlight you get, and how bright it is) not an influence on the voltage produced by a solar cell?
bluesmoke...oops
Senior Member
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- Tri-Cities, Washington
Are we referring to the system as a whole, or down to specific solar cells? And are we talking a strictly DC system, or an inverted AC system?
Voltage in a Solar System can mean a lot of things
Voltage in a Solar System can mean a lot of things
IMHO ... the question is not specific enough. "Voltage in a Solar System". Too many variables are involved. Here is my answer:
1. Distance from the sun or other nearby star.
2. Proximity to a nearby planet or other body with a significant magnetic field.
3. Orientation of the voltage sensing device.
:grin:
Voltage in a Solar System can mean a lot of things
IMHO ... the question is not specific enough. "Voltage in a Solar System". Too many variables are involved. Here is my answer:
1. Distance from the sun or other nearby star.
2. Proximity to a nearby planet or other body with a significant magnetic field.
3. Orientation of the voltage sensing device.
:grin:
bluesmoke...oops
Senior Member
- Location
- Tri-Cities, Washington
My answer would be whatever the voltage of the system it is supplying.
- Location
- Massachusetts
Solar panels are current sources, not voltage, and current is proportional to the amount of light. Second clue is temperature. Charles look at any IR curve and you will see what I am saying. Look for Voc, Vmp, Imp, Isc, and Temperature Coefficient. Hint Voc is what you want to know, and Voc is only affected by three things, Voc rating of a single panel, how many panels in series, and temp. Amount of sun light has nothing to do with it. When open circuit a flashlight will develop Voc.And how is it that "solar radiation" (i.e., how much sunlight you get, and how bright it is) not an influence on the voltage produced by a solar cell?
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2 of 3 correct. Irradiance determines current, not voltage.
Here is the deal. A solar panel is a CURRENT SOURCE not a voltage source in the operating region. It acts like a voltage source only from Voc (voltage open circuit) to Vmp (voltage maximum power). You never want to operate a solar panel between Voc and Vmp. You want to operate at Vmp. Hence why MPPT is crucial aka maximum power point tracking.
From Vmp to Isc (current short circuit) the panel operates as a CURRENT SOURCE.
In design of a solar system the only voltage NEC and equipment is concerned with is Voc. Voc is a product of the individual panel specification, number of panels in series, and the temperature. Assuming the panel has any irradiation exposed to it, even if from a flash light, it will develop Voc. When a solar PV system is exposed to -50 degree temp on a bright sunny warm day, the Voc will be at it highest. Well unless the temp drops to -60 on a bright sunny warm day.
So the correct answer is
From Vmp to Isc (current short circuit) the panel operates as a CURRENT SOURCE.
In design of a solar system the only voltage NEC and equipment is concerned with is Voc. Voc is a product of the individual panel specification, number of panels in series, and the temperature. Assuming the panel has any irradiation exposed to it, even if from a flash light, it will develop Voc. When a solar PV system is exposed to -50 degree temp on a bright sunny warm day, the Voc will be at it highest. Well unless the temp drops to -60 on a bright sunny warm day.
So the correct answer is
- Panel Voc rating at 25 C
- Number of panels in series.
- Temperature coefficient rating
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nick panaro
Member
you guys have really helped me to understand a little more. thank you
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
101118-2011 EST
See http://zone.ni.com/devzone/cda/tut/p/id/7230
To find information like this use a Google search string similar to the following:
voltage current curve for a solar panel
.
See http://zone.ni.com/devzone/cda/tut/p/id/7230
To find information like this use a Google search string similar to the following:
voltage current curve for a solar panel
.
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