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Posts: 10
Reply with quote  #1 

Hello, I am setting up an off grid solar system that I need some done it themselvers approval.

If I start by getting this Charge controller:


20amps, with four regony 12volt 5.6amp panels paired to 24 volt running on a 10 awg 100' cable.
In a calculator I found that you loose 2.7amps (I am not sure if that is one way, or 2.7 for both ways if so I would drop the cable length to 50').
That would drop the 22.4amp down to 19.7 max.


Would this system fly? I prefer to not spend a lot of money right now and just get two regony panels with a MPPT controller that can accommodate more as I need.

Also does anyone know of a good place to buy panels near seattle? everywhere I have looked has shipping costs almost as much as the panels themselves.


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Posts: 534
Reply with quote  #2 
I bought these on Amazon about 8 months ago.

No added shipping. Not sure if they have the panels you are looking for.

Here's the controller I have:

Bert K.


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Posts: 2,874
Reply with quote  #3 
The specs on the controller say max BATTERY current is 20 amps. If you use a 24v battery system it would work, if a 12v system, probably not.

The specs also say max PV input power is 260w for a 12v system, or 520w for a 24v system. You could wire all 4 panels in series for efficiency.

Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay

Posts: 9
Reply with quote  #4 
What you have to remember is that the power loss in a cable is equal to the resistance of the cable times the current squared. What that means is that if you have 10 amps traveling in a wire that has a resistance of 1 ohm then the loss is equal to 1 times 10 squared equals 100 watts. The voltage drop is equal to the current times the resistance. That would be 1 times 10 equals a 10 volt loss.  There is a project that I am working on that requires 25 volts at 4 amps about 300 feet away. I have to put another solar panel in series so that I get 25 volts to the dc motor on the other end of the line running the swamp cooler. Al
involute reflection

Posts: 13
Reply with quote  #5 
a nominal 20 amp array can put out substantially more than 20amps on a cold semi cloudy day due to reflection.
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