Rivian reduced electrical wiring by 1.6 miles and 44 pounds

Original Article ↗ Hacker News Discussion ↗

Wireless vs. Wired Communication

  • Several commenters ask why not use Wi‑Fi / RF to cut more wiring.
  • Most responses oppose this for critical systems: higher latency, greater susceptibility to interference and jamming, no shielding, and much larger attack surface.
  • EMI in EVs is already problematic (e.g., AM radio issues); adding more RF for safety‑critical links is seen as risky.
  • Wireless is already used in constrained niches (tire‑pressure sensors, some battery management inside packs), but commenters stress it’s for non‑critical or hard‑to‑wire cases.
  • In home/hobby contexts, some embrace RF for convenience; others deliberately avoid Wi‑Fi for security and reliability, preferring wired or protocols like Zigbee/Z‑Wave.

Zonal ECU Architecture & Failure Modes

  • Discussion compares domain‑based ECUs (per function) vs zonal (per physical area).
  • Concern: a zonal ECU failure could knock out many unrelated functions in that zone (locks, windows, seats, fans).
  • Others say Rivian keeps safety‑critical domains (drive, battery, access, autonomy, infotainment) on dedicated ECUs; zones handle “small but important” loads.
  • Multiple comments note that distributed real‑time systems are hard: state management bugs already appear in existing cars.
  • Some advocate “dumb” edge I/O with centralized logic to simplify reasoning; others point out this re‑introduces single points of failure and wiring.

ECU Count, Modularity, and Suppliers

  • Many like the reduction from dozens/hundreds of ECUs; others note legacy designs allowed reusable modules across models and suppliers with different safety/reliability levels.
  • Rivian’s approach is seen as enabled by strong in‑house software and modern heterogeneous processors, whereas traditional OEMs are constrained by tiered suppliers and organizational inertia.

Wiring Length, Copper, and System Voltage

  • Back‑of‑the‑envelope math in the thread finds Rivian’s 1.6‑mile / 44‑lb copper reduction plausible.
  • Commenters doubt the quoted 20% material and 15% carbon savings come from copper alone; broader simplification is implied.
  • Several point to 48V low‑voltage systems (as in Tesla) as the next major step: same power with far lower current, thinner wires, and less copper.
  • Others discuss safety limits around ~50–60 V DC, tradeoffs, and the complexity of multiple voltage rails.

Broader Themes and Comparisons

  • References to Tesla’s past wiring‑reduction plans and Cybertruck architecture; curiosity about Tesla’s “unboxed” distributed ECUs vs Rivian’s more centralized zones.
  • Some feel modern cars are over‑complex (hundreds of ECUs, massive compute for cameras/radars); others note regulations now require advanced driver‑assistance anyway.
  • One commenter links wiring complexity to Conway’s law: harness layout mirrors organizational and supplier boundaries.