Solar Controller/ Wire Size Suggestions

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On The Rocks

Senior Member
Joined
Apr 13, 2012
Messages
109
Location
USA
Vessel Name
On The Rocks
Vessel Make
Gulf Star MKII
I have two Sunpower 327 watt panels that I plan to put on the fly bridge hard top wired parallel. I want to use an MPPT controller mounted about three feet from my 12 volt house bank. The wire run from the panels to the controller is 35 to 40 feet.

Any suggestions on brand/size of controller?

Suggested wire size from panels to controller?

Suggested wire size from controller to batteries?

ImageUploadedByTrawler Forum1442163993.793345.jpg
 
To spec a controller you need the Voc value above and the output current. In your case the output current would be (2x327)/12 = 55 amps. So you need a controller with a Voc of 65 or greater and an output current of 55 amps or greater.

Since your panels are very high voltage- 65 Voc, they will require a high end controller. Most controllers are only good for 40 V. The Outback Flexmax 60 should work. Other possibilities are made by Blue Sky and Magnum Energy.

Use the Impx2 to size the wire from the panels to the controller. To keep the voltage drop below 3% you will need 6 gauge wire from the panels to the controller and the same from your controller to the batteries.

David
 
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