[Dake]

Don't forget there's a second power port in the glove box (it's what my dashcam plugs in to). It's not hot either, but it might be handier for keeping stuff tucked away.

If anything could be modded it'd be the cigarette lighter I'd think. That being said, you'd be surprised how fast a modern cell phone battery can deplete a standard car battery to below the point it can start the car. I did it to myself once and it didn't take long (though to be fair, it was the original battery and it was on its way out anyway).