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Post Info TOPIC: Solar Panel ratings


Senior Member

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Posts: 131
Date:
Solar Panel ratings


Can someone  explain please with solar panel ratings, what is the difference between open-circuit voltage and max power voltage, and also max power and max power current?

Joe



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Guru

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Posts: 975
Date:

Hi Joe smile

This is a random panel off ebay.

SPECIFICATION:
Maximum Power(Pm): 200Wp                         This a nominal power rating under special test conditions. Not achieved often in the real world, you only get 70-80% of that.disbelief 
Open-Circuit Voltage(Voc): 21.42V                  The max voltage produced when not connected and no current used. Important to know for the safety of the regulator life. 
Short-Circuit Current(Isc): 12.22A                   The max current under test conditions with the leads shorted together. Not achieved in the real world. 
Maximum Power Voltage(Vmp): 17.5V           The important voltage produced under test conditions to get max power out of the panel. Use this for comparing panels. 
Maximum Power Current(Imp): 11.43A          The important max current produced under test conditions to get max power from the panel. Use this for comparing panels.

Standard Test Conditions: 1000W/m˛, AM1.5, 25°C     These are the test conditions used for the panels. In the real world on a caravan roof these do not apply. EG The sun does not always shine as strong as that. It is not always straight above the panel. The temperature is much higher and that is bad for the power output.

Cheers Jaahn



-- Edited by Jaahn on Saturday 5th of May 2018 02:14:12 PM

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Senior Member

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Posts: 131
Date:

Thanks Jaahn. smile

Model: VASPBAG-2G

Max Power: 150W

Open-Circuit Voltage: 21.65V

Short-Circuit Current: 10.10A

Max Power Voltage: 18.3V

Max Power Current: 8.2A

Solar Cell: SUNPOWER Regulator Type: 12/24V PWM Extension Lead: 5M Folded Size: 55 x 54 x 3 cm Unfolded Size: 1650 x 540 x 3 mm Weight: 4.0KG

These panels have only 32 cells  (4 x 8) with  max power voltage 18.3v. Hmm, this = .57v per cell.

Can it be that high per cell?

Joe



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Guru

Status: Offline
Posts: 975
Date:

Hi Joe smile

Do they have special technology that no one else does ??? who knows. I do not ! Draw your own conclusion.

I looked at some pictures of that item being sold. It looked like they had 48 cells ??? That does not match either.confuse

When I see this BS I am not impressed !

List price:
AU $1,250.00 
You save:
AU $763.05 (61% off)
         Now:   AU $486.95
        Free postage;  (thank heavens for that !)disbelief

Jaahn



-- Edited by Jaahn on Saturday 5th of May 2018 06:53:21 PM

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Senior Member

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Posts: 131
Date:

Thanks Jaahn, I paid $399 with free overnight post.

Joe.



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