> On top of that 12v instrumentation is (obviously) on a different power level than an electric engine, so the batteries will be different.
I wouldn’t count this as “obvious”. The Tesla Roadster, for example, operated its low voltage system using a DC-DC converter that was supplied by the HV system. Tesla decided this was a mistake in the Model S and added a 12V battery.
(Sadly, they seriously flubbed the charging logic for the 12V battery, and the Model S destroyed 12V batteries quickly. It took a couple years before the firmware was fixed to solve that problem.)
I wouldn’t count this as “obvious”. The Tesla Roadster, for example, operated its low voltage system using a DC-DC converter that was supplied by the HV system. Tesla decided this was a mistake in the Model S and added a 12V battery.
(Sadly, they seriously flubbed the charging logic for the 12V battery, and the Model S destroyed 12V batteries quickly. It took a couple years before the firmware was fixed to solve that problem.)