It is a common misconception that inverters are needed for everything that plugs into a wall. Inverters are generally required only for devices that run off wall power with cord that runs permanently into the device. Example: table lamp.

Devices that have a “wall-wart” power adapter that can disconnect from the device are typically using DC power, which is what is already in your car. No inverter needed. The adapter is there only to change 120vac to the required amount of DC voltage.¹⁾ If you inspect the device or adapter it will usually indicate something like:

• 12vdc, 2A (24w)
• 5vdc, 1A (5w, typical with usb)

19vdc is the modern standard for charging laptops. You can buy a 12vdc –> 19vdc adapter as an accessory from your laptop manufacturer or buy a generic one with various plugs.

The car's own power system (and likely your aux power system) is already 12v. So if the device runs off 12v you can power it directly off power system: 12vdc –> device. If you did it from an inverter instead you'd be going 12vdc (car) –> 120vac (inverter) –> 12vdc (adapter) device, with added complexity, inefficiency and cost.

5vdc is most often seen in USB. If your device needs 5v²⁾ you can likely run it from a USB to plug adapter. Example. You will have to assess the plug size.