[RE-wrenches] Solar Boost Controller in Senegal

[Wind-sun.com]

Yes, it is a poor design. though you may not have any problems there with the heat de-rating of the panels. If the panel temperature gets under about 40C you may blow out the input. As long as you have a load on the output of the contgroller, it will keep the voltage down, but if the output is disconnected the input could go up to full voltage.

Who designed such a system?

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  ----- Original Message ----- 
  From: Walt Ratterman 
  To: 'RE-wrenches' 
  Sent: Friday, June 26, 2009 3:22 PM
  Subject: [RE-wrenches] Solar Boost Controller in Senegal


  Hello,

   

  I am in a very remote part of Senegal, (near the Guinea  and Mali borders…) and I have come across some prefabricated “plug and play” American made systems installed for educational institutions.

   

  The systems use two Sharp panels that are 220Watts, 33.6 Voc, 29.2 Vmp, wired in series, using #10AWG home run wire from the panels back to the charge controller.

   

  Charge Controller is a Solar Boost 50.  

   

  Batteries are Dekka AGM – two strings of 250AH, 12V batteries.  (four batteries total).

   

  My specific question is about the controller.  This is a 24V in / 24V out charge controller with MPPT.  I have not used this before, so I am not familiar with the details of operation.

   

  The data sheet that I downloaded says that the maximum open circuit voltage is 57 VDC.  But, this system is hitting the charge controller with two panels of 33.6 VDC wired in series for 73.2VDC.  So, why is the controller not fried, or what am I seeing wrong here.  I suppose with the panel temperature being elevated maybe 35 degrees above 25 degrees and a resulting 17.5% loss, coupled with some voltage drop, the system may actually be seeing less than the 57 volts.  

   

  But…..isnt this a dangerous way to design a system?  (it will get cooler here ….)

   

  Or am I missing something? 

   

  What would be the appropriate application here….

   

  Sorry, I cant do a lot of internet research from here – limited download capability on the satellite….

   

  Thanks!!

   

  Walt

   

  Walt Ratterman

  SunEnergy Power International

   

  11 Laurel Lane South     Washougal, WA   98671

  (360)-837-3680   ▪   fax (360)-837-1315   ▪   Skype  Walt-Mobile

  wratterman at SunEPI.org   ▪   www.SunEPI.org

   

   



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