Can you show the hud? Never seen one and apparently it can't be filmed so no video review shows it. Is it really across the whole windscreen?
Not as easy as you think. The 12V battery _is_ allowed to draw the power from the main, that's how it's recharged while the car is "on" (via a DC-DC converter, basically equivalent to an alternator/generator on a running engine). However, when the car is fully "off", the main battery is hard disconnected on the contactors (very large relays) as to make the high voltage system of the car safe. When they are disconnected, the 12V system is "on its own" - nothing draws power from the main pack, including the DC-DC system. The 12V is also needed to re-engage the contactors and enable the HV system again, which is why the car cannot be charged or used at all if the 12V runs empty.This issue would be easy to solve by allowing the 12v battery to be able to draw power from the main EV battery