I'll go later clips (alligator clips)

I was going to improve them with copper strips. You could also cut strips from a tin can and solder to those for some metallic jaws.

But you know what, these are fine as-is. They don't rust or short, and they are super easy to fix when they wear out. Just strip the wire back about 1.5", twist the ends, and push them thru until you can grab them with needle-nose pliers. Then force the insulation into the holes using a twisting motion.

These are hooked to a small, emergency bilge pump that sits in a drawer with a short length of garden hose and is never used. Everyone should carry a spare, or two that you can toss to a friend in need. Draw is < 5A.

The wires are bound-in tightly with friction. And they're actually kind of difficult to pull out.

If they pull out too easy, make the holes smaller or use the 3d pen to weld them in a bit. Happy printing!

Printed with PETG on default settings, 240°C. No supports, etc.