For wire we use standard automotive wire that we get at a local auto-electric shop (not a chain store) and they give us the contractors rate. It's got good flexibility and we're never had problems with it. We usually twist the black and red wires together by clamping the pair together in a drill while someone holds the spools at the other end of the room.
For wire-to-terminal connections, the quality of the connection follows this hierarchy:
- Best: good crimp (note that a good crimp requires a good crimping tool)
- Acceptable: crimp + solder (the primary reason that this makes a lesser connection is that the solder makes the connection brittle. For all soldered connections, it is important to make sure that solder does not wick up the wire)
- Bad: bad crimp
For ring terminals and connections that shouldn't need to be unplugged, we use Ideal (the brand) crimp terminals and quick connects from Home Depot and crimp them with a crimping tool similar to
these, that we got from Fry's. You have to calibrate the crimping tool when you get it (adjust how tightly they crimp), otherwise they'll make trash crimps. In all our years of using this tool, I can't think of a single crimp failure that can't be blamed on either using the wrong size terminal for the wire size or not inserting enough copper into the connector.
We use PowerPoles for most wire-to-wire connections. We use the crimp + solder method because the PowerPole crimping tool is pretty expensive, although I'm pressuring the team to get one.
For the battery lugs we use the crimp lugs that come (or at least came) in the KOP (not the screw type). Because we certainly can't afford the proper crimping tool for these, we solder the connection following these steps: First, if the barrel doesn't have an opening on the ring side, drill a small hole to feed solder. Next, push the wire into the connector and try to fill all the free space around the wire with solder (do this before applying heat to the connector). I do this by pushing the solder straight into the connector, cutting it flush with the connector, and repeating until I can't get any more solder into the connector. Then, take a propane torch and heat up the connector until the solder flows. You can use a soldering gun, but the torch is
much faster. Finally, feed solder into the small hole you drilled in the connector (this time, keep the connector hot while adding solder). Only add solder from this end to help keep solder from wicking up the wire. Stop adding solder before any is able to wick up out of the connector.
For most of our heat shrink, we use the
variety pack from Fry's. It's nice and flexible to reduce the strain on the wire. There are befits to higher quality heat shrink, but it's rarely worth it for what we do.