The $480-$1,130 per vehicle cost premium for 800V over 400V estimated in this audit is a composite inference from analyst reports. No OEM publishes detailed bill-of-materials comparison data. The actual cost premium is confidential in every OEM supply chain.
The three components with highest uncertainty: (a) SiC MOSFET cost at current production volumes — Wolfspeed, STMicroelectronics, and Rohm all negotiate volume pricing confidentially; Chinese domestic producers (BYD Semiconductor, CREE China) have not disclosed pricing; (b) whether Chinese domestic SiC production is reaching quality standards sufficient for 800V automotive inverter application at scale — production announcements exist but yield rates and quality certification status are not public; (c) the actual learning curve rate — analyst consensus assumes 15-20% cost reduction per doubling of production volume, but this has not been validated against disclosed contract data.
The cost crossover year (2027-2029 analyst consensus) is the single most commercially important figure in the 800V investment thesis. An investor taking a position on SiC supply chain companies or 800V vehicle OEMs based on a 2027 crossover assumption is taking on model risk that the underlying data does not support.
What would resolve it: OEM disclosure of 800V vs 400V cost differential in annual reports or investor presentations. Wolfspeed, STMicro, or Rohm disclosure of volume pricing tiers. Either is unlikely in the near term given competitive sensitivity. The most actionable alternative: monitor SiC wafer spot pricing through Yole Group quarterly reports, and track OEM gross margin trends for 800V model lines as a proxy for cost trajectory.
Last verified: March 2026. No OEM has published 800V vs 400V BOM cost comparison. SiC contract pricing remains confidential across all major suppliers. Status: OPEN.