I did one of those for my Outback. The connectors are also known as "Anderson connectors." I also made a 20" long jumper cable out of welding cable with a connector. Came in handy being able to sit behind a car and jump them.

I recommend you get the screw in cable holders (these) for them to take some of the strain when you pull them. Also... don't cheap out and try to crimp them. Solder it in place, I used a propane torch.

 

Are welding cables what people are using now? This is something I'd like to add down the road- safety and convenience factor.

 

Nothing wrong with crimping the connectors, with the proper tool.
I have 4 sets of this style connector of various sizes. Some are crimped, some are soldered. All are performing well.