For Electrical use, always use Flux core solder. Acid core solder (for plumbing)will corrode.

For cable, you can NEVER go too big!!

Greg

I had to run new cable when I was redoing the charging system when i had my boat. I found a welding supply house cheaper to buy any gauge wire as opposed to Lowes or Home Depot.

NIK.

Greg had it right..acid core/flux solder is for plumbing only.

Resin core/flux solder for everything else.

I found that out early on in my work life, I mistakenly used acid core on an electronic repair...that stuff etched the copper runs right off the PC board. :Duh::Duh:

It is also better to use tinned copper wire which is also the go-to stuff for use on boats.
And use wire that consists of many fine copper strands versus a few large strands.

I had a cable made a couple years ago from this site. They use top quality marine grade components. It only cost about 10.00 shipped to my door. I think I used 4 gauge with heavy duty ends and shrink tubing.

http://www.genuinedealz.com/custom-cables