Unfortunately that's not the case. There are other devices (heaters, AC, etc.) that need power at different voltages than the primary battery, so there are swi

Unfortunately that's not the case. There are other devices (heaters, AC, etc.) that need power at different voltages than the primary battery, so there are switching converters. Some of those are rather noisy. One of the many youtube hams that also happens to have a Leaf points out that despite applying comprehensive body grounds, line chokes and other measures a Nissan Leaf's AC will zero out most of the HF bands when he is operating mobile.