Back when I had a USB hub in the trunk for the car computer, I specifically picked one that took 12V in and could handle some variance. Recommendation came from the MP3Car community about 10 years ago.

Checking back in, it looks like they now have a store with a 12-24V car specific hub, and it's also available via Amazon.

Looks like that one only does the standard 500ma USB 2 power. Did also come across this USB charger specific one that you could potentially wire in directly instead of using the lighter socket.