Alternative Technology Assn Forums

1. 

   Flyman
   Member

   Hi to all, this is my first post as I am new to the forum and I am hoping someone can help.
   I am about to start installing 6 solar panel on my house in Spain. The panels are Sharp 24v 185R 1H, they produce 7.7amp with an ocv of 30.2 and they are going to an Outback Flexmax 60amp controller. As I understand I could connect them in 2 ways: either 2 strings of 3 panels (in series), or 3 strings of 2 panels, again in series. I think either configuration would work but wonder if one had any advantage over the other?

   Posted Saturday 10 Nov 2012 @ 9:41:53 am from IP #
2. 

   rockabye
   Member

   A lower voltage, 2 panels X 3 strings, is probably slightly less hazardous and a failure of one string leaves 4 panels still working. While the higher voltage configuration is slightly better with regard to lower cable losses and possible lower cabling costs. As you say either will work. edit looks like a consensus to me

   Posted Saturday 10 Nov 2012 @ 10:12:20 am from IP #
3. 

   LanceTurner
   Key Master

   To reduce I²R losses, higher voltage with lower current is better, so strings of 3 would be my preference. There is the issue that, generally, stepdown switchmode converters are more efficient the closer the input voltage is to the output voltage, but the "spec sheet" for that doesn't give an efficiency curve so there's no way to know what the difference is in efficiency at the two input voltages.

   Posted Saturday 10 Nov 2012 @ 10:13:07 am from IP #
4. 

   LanceTurner
   Key Master

   And there you go, two different sets of considerations

   Posted Saturday 10 Nov 2012 @ 10:13:36 am from IP #

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