Even if it does charge, it's not likely to charge well; the Nexus 4's charger is 1.2 amps. The Xbox USB ports likely put out less than half that. Unless you have an S model, in which case the rear "Kinect" port is "high-powered," which likely means 1.0 amps.

I'm charging off my AirPort Extreme without issue...albeit it slow. Since I charge at night, it's a non-issue. OP, have you tried swapping USB cable?

Does the Xbox 360 temporarily disable its USB port if you try to pull to much power from them?
The Nexus 4 requires more than what is supplied...

uberSlackr could be right, normal usb ports are 5volts,500mah, so 5 volts standby, you should be able to charge even at a slow rate, windows 7 has an option to turn off usb ports to save power unless you disable it.maybe xbox has a similar power saving function.

samsung s2 max charging rate is at 650mah, my nexus charger is 1.2amps, so 1 amp draws too much.

Originally Posted by tibere86

I'm charging off my AirPort Extreme without issue...albeit it slow. Since I charge at night, it's a non-issue. OP, have you tried swapping USB cable?

yes, i've tried changing the cable and its the same... i believe the comments above have explained it much clearly to me and make me understand why its not charging (xbox usb being 500 mah and the phone needs 1.2 amp... so looks like i will have to use my wall charger from now on)

i appreciate the help guys!!