electrical vehicles often have two battery systems - a 12v, 24 or 48v battery for the accessory systems like your windshield wipers and radio, ECU, door locks, windows etc - and the high voltage power system that runs the motors.
why not run it all on the high voltage system? tbh, I think we’ll get there eventually, but atm it’s easier to isolate them from each other so you never get 400v going to the driver window or other accessories. For the last 100ish years all these systems - motors for windows, wipers, seat adjustment etc all ran on 12v. Auto manufacturers redesigning everything from the power perspective didn’t make a lot of sense when it’s all available off the shelf if you can feed it 12v. And considering the vagaries of charging the high voltage systems, having a separate 12v means even if the fancy shit goes tits up, you should still be able to unlock the door or turn on the hazard lights.
IIRC Hyundai even has a crossover circuit that you can engage to allow you to jump the low voltage system off the high voltage pack, but I have no firsthand experience with this.
electrical vehicles often have two battery systems - a 12v, 24 or 48v battery for the accessory systems like your windshield wipers and radio, ECU, door locks, windows etc - and the high voltage power system that runs the motors.
why not run it all on the high voltage system? tbh, I think we’ll get there eventually, but atm it’s easier to isolate them from each other so you never get 400v going to the driver window or other accessories. For the last 100ish years all these systems - motors for windows, wipers, seat adjustment etc all ran on 12v. Auto manufacturers redesigning everything from the power perspective didn’t make a lot of sense when it’s all available off the shelf if you can feed it 12v. And considering the vagaries of charging the high voltage systems, having a separate 12v means even if the fancy shit goes tits up, you should still be able to unlock the door or turn on the hazard lights.
IIRC Hyundai even has a crossover circuit that you can engage to allow you to jump the low voltage system off the high voltage pack, but I have no firsthand experience with this.