I want a subwoofer for my car but I don't want to mess with the battery and stuff. Is this possible?

I just bought a brand new honda civic hatchback (2017) and I want to add a subwoofer to the back. I've never done anything like this so i don't want to mess with that much stuff. I was wondering if there's like a subwoofer that I can attach to my phone with an aux splitter or Bluetooth. I know that subs take a lot of power so i'm wandering if a good one that I can just charge exists. Please let me know.

Consult with a local car stereo dealer.

Tell us how that works out. The sub must be powered and the only source you have in the car is NOT your phone, I don't care how geewhiz the phone is. The battery will need to be connected to run the amp.