Yes, as I recall when I was using a Roku 3, it used its own 12v adapter rather than the 5v USB connection used by most models.
I suppose you could use an automotive inverter to give you a 110v AC outlet to plug your existing Roku 3 power supply into. You can find models that plug into the cigarette lighter socket. I used to use one when camping for charging and running a laptop.
Roku Community Streaming Expert I am not a Roku employee, only a user like you. Do not ask me support questions via private message -- post them publicly to the Community where others may benefit as well.
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