Battery Cables?

That is why they make wire nuts, best things since zip ties.

i use lead wire and i soldier my ends and it seems to work fine for me.

You're basing all crimped connections assumptions on a 3 cent spade connector that you crimp with pliers?
Last time i checked a fuel pump aint high current.
The ones i'm talking about use a multiple ton press and die's to squash them. They NEVER come apart.
the connection is Positive, direct from conductor to the end.
Soldered joints are negative joints, the conductor and end never touch, and they rely on a substance that has an awfully low melting point to make a connection in a circuit that can heat up past that point.
The problems may not show up like you think. It most likely will eat starters and burn out alternators rather than turning the key and having no power.