If you have more than one person in the car with you, that means that more than one person is going to want to charge their phone. But you're using your GPS and it's sucking your battery, and they want to play their music.
Solve all your problems by getting a mount that actually charges your phone. You can free up that USB space for things other than phone charging purposes by easily installing this guy into your air vents and letting it charge right up.
Model Number: Baseus Gravity Wireless Charger Car Mount Holder Output: 5V/2A Support Quick Charge Technology: Qualcomm Quick Charge 3.0,Qualcomm Quick Charge 2.0 USB Ports: None Quality Certification: RoHS,CE,FCC,CCC Output Interface: USB Type: Wireless Charger Compatible Brand: Universal Power Source: USB Brand Name: BASEUS Input: 12-24V/2.4A