As much as the fuse will allow. Can't remember what fuse number it is but check the Rave or look on your truck.

 

Rave says it's a shared fuse 20 AMPS.

Fuse #15 20Amps
Cigar lighter
Interior lights
Seat heaters
Vanity mirror illumination

 

I have plenty of wire so I guess I will just run it to the battery to save the delicate Rover electronic circuits. What size fuse should I use for the inline fuse.

 

3 Amp fuse should be fine. They should only charge at most 2.1 Amps.

 

I would tap into the cigarette lighter circuit. The "delicate" electronics are much more likley to get disturbed by the process of running the wire back to the battery and the adapter will never draw more than an amp or so. It is a PWM converter and power, not current, is the issue. (Power = volts times amps).

 

How can running a wire from the battery affect the rest of the electrical system?

 

It's a Rover that's why.
I use these and they work great.

 

So y'all are saying it is better to risk overloading a circuit than running a new one?

 

There is no possible way to "overload" the cigarette lighter by running a usb charger from it unless the charger becomes defective. Then, the fuse blows and you replace the charger and the fuse. Until you do, the cigarette lighter does not work. The engine doesn't fall to the ground, the gas tank does not blow up, the ecu does not fail and so on.

My statement about affecting the existing wiring is that while you are snaking the wire in, you might skin another wire or dislodge some connector, or make a new less watertight penetration. Not likley, but just sayin, there is risk in anything.

BTW, when you plug your phone charger in at your house, do you worry about blowing your TV?

 

I use what I displayed above because I don't like tapping into existing wiring. Very difficult to troubleshoot later. Plus I know that it is on a dedicated circuit.