As well as high voltages, you need to move signals cleanly around your EV. For that I’ve purchased a reel of 25m of shielded twisted pair (STP) Cat5e cable with an outdoor-rated waterproof sheath and grounding wire. We’ll see how that works. I’ll likely sheath it further in something to give it extra protection in the engine bay environment and when it has to run down the car to the battery packs in the rear.

UPDATE: THIS IS THE WRONG STUFF FOR THE JOB

Turns out that the this stuff is too thin to be properly crimped into most of the connectors that are typically used in an automotive environment. You really need something of 20AWG/0.75mm² or above. I’ve now ordered some 7 core CY Flexible Control cable designed for industrial environments to see how that fares.