Which battery in an EV powers vehicle electronics and accessories and is charged by the HV system or DC‑DC converter?

• A. The traction high‑voltage battery.
• B. The 12V auxiliary battery.
• C. The starter battery only when the engine starts.
• D. The solar storage battery.

Answer: (B)

In an electric vehicle, the electronics and accessories run on a 12V auxiliary battery. The high‑voltage traction battery powers the vehicle’s drive system, but it isn't used directly for the 12V electronics. Instead, a DC‑DC converter takes energy from the high‑voltage system and converts it to 12V to charge the auxiliary battery and supply the low‑voltage electrical system. This keeps lights, infotainment, sensors, controllers, and other 12V components powered reliably, even as the high‑voltage system handles propulsion. The other options don’t fit because the high‑voltage battery is for drive power, not routinely for 12V electronics; the “starter” battery concept is tied to internal combustion engines and isn’t how EVs typically power their electronics; and a solar storage battery isn’t a standard primary power source for vehicle electronics.