Question about wire sizing

[wilfor03]

I'm building my solar "system" as I go and am getting ready to purchase some #4 AWG to go from the solar panels (encased in 1 1/2" grey PVC piping) to the power panel (controller, Sunforce 30A-12v) in the workshop (setup for #10 or #8 wire). What is the correct way of "matching" the 2 different wire sizes? Should I use a bus bar or copper wire lugs or what? Does anyone have any pictures of their connections handy.    Thanks in advance for the help.....Bill

[dlenox]

Bill,

On my 48v (nominal) system, I have 4 panels wired in series (25v each) and they typically give me about 90-100v total, which feeds into my charge controller.  This charge controller steps the voltage down (and increases amps) to feed directly into my 48v battery bank.

So on my system I am running #8 wire straight through from the array to the DC disconnect which the charge controller connects to.

I'm guessing then that your solar panel(s) put out a total of 12v, and this feeds into a 12v charge controller - and that is why the large diameter wire - for less voltage loss?  If so then get yourself a cheap busbar and put it inside your DC disconnect (you do have one don't you? code usually requires it!).  This way the large diameter incoming wire can easily be adapted to what you have inside your house.

Dan Lenox

[ghurd]

Power Distribution Blocks?
Ebay has pics of about 100 versions.

I use quite a bit of car stereo power parts.
G-

[wilfor03]

Thanks guys...just sniffed around on flea-bay and found exactly what I needed......as always, I do appreciate the shared knowledge/wisdom of you ole men (LOL- I'm only 62!!)    The stereo stuff fits the ticket.....Thanks again, guys......Bill