Some Hyundai hybrids and PHEVs have this (I saw it in the original Ioniq). It's a button you press that temporarily charges the 12V battery through the high-vol

Some Hyundai hybrids and PHEVs have this (I saw it in the original Ioniq). It's a button you press that temporarily charges the 12V battery through the high-voltage system rather than being always enabled, but it seems like a great idea.