When electric hovercrafts are available, the technology parts that are used to make the high voltage transformer aren't dependencies to these vehicles in the technology tree, which results in the ability to research and build electric-hovercraft before they can be charged.

This is much worse in Space Exploration, where personal battery MK2 is a much later technology, which broadens the window of time where electric hovercrafts are useless. (In my server some made hovercrafts and they've been unusable for a couple months)