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Newbie needs help with solar panel planning

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Open circuit voltage cannot be higher than 150v,  max voltage on a system is 72 vdc . Need help in finding the best  suited solar pannels with proffered setup whether in parallel or series or series parallel.

 

I have 2 x 360w and 1 x 350w pannels.

 

Thank you in advance.

You will need to supply the voltages of the panels to make an informed answer. You might get all 3 in series if the voltage is low enough, but maybe only 2 with a low voltage scc.

@ANDREWOSMOND,

Your Voc on those panels should be around 47V (I have 365W CanadianSolar). 

2P will give you 94V @ 25 Deg C. That you will see early mornings/late afternoons. However, you also need to compensate for some minus 5 deg temps here on the highveld.

Temp Co-eff. = +- 0.28%/Deg C. Thus 25 to (max) -5 Deg (extreme) = 30 deg. 

0.28 * 30 = 8.4%. Thus 94V + 8V = 102V. So still within the Voc max of your system. 3S should be around 153V, so not a good plan.

Under load, you will see a voltage drop (in theory 44V x 2 = 88V) for 2S. Also too much for your system. 

So 1P/2P/3P may be the only option, depending on the max current that your system can handle. The Imp for my 365W panels is 7.21 Amp, so your should be close/less that that.

Hope this helps somewhat.

6 minutes ago, Sidewinder said:

@ANDREWOSMOND,

Your Voc on those panels should be around 47V (I have 365W CanadianSolar). 

2P will give you 94V @ 25 Deg C. That you will see early mornings/late afternoons. However, you also need to compensate for some minus 5 deg temps here on the highveld.

Temp Co-eff. = +- 0.28%/Deg C. Thus 25 to (max) -5 Deg (extreme) = 30 deg. 

0.28 * 30 = 8.4%. Thus 94V + 8V = 102V. So still within the Voc max of your system. 3S should be around 153V, so not a good plan.

Under load, you will see a voltage drop (in theory 44V x 2 = 88V) for 2S. Also too much for your system. 

So 1P/2P/3P may be the only option, depending on the max current that your system can handle. The Imp for my 365W panels is 7.21 Amp, so your should be close/less that that.

Hope this helps somewhat.

Full details of panels on this topic.

 

  • Moderator2 changed the title to Newbie needs help with solar panel planning

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