These are what I use. Klein... Never had a butt connector pull apart with these.
[Linked Image from live.staticflickr.com]

and these heat shrink connectors. put a squirt of dielectric grease in each one before you crimp the wires and heat shrink. Never had a problem with the connection going bad. This is How I work the wires on my boats.
[Linked Image from live.staticflickr.com]

I know a lot about a lot of things BUT I still have a lot to learn.
Life is what you make of it. So, why not make a working machine to make it easier.