I am no expert on this particular brand. But i think you are in for an Arizer Solo or Solo II . They are battery operated,have separate PSU for the passtrough and for charging at least it is so with the classic solo,it can be charged/used with passtrough in a car ,but you will have to buy all the extra accesories needed for the task.
Another one that comes to mind is the Insta-heat a.k.a iHeat .It can run off 12v supply and off a mod box battery which you will have to buy separately + there might be a waitlist on this one
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