I have a PSU that can put out 60A @ 4.8-5.25v (about 300W) as well as one that does 2x that. I was wondering what would happen if I took some USB cables and just connected the +/- (and/or ground I guess) into the output of the PSU. If a cell phone charges at 2A then I could hook up 30 devices (on the 300w) but what I'm wondering is do the cell phones draw as much current as they can/need or do I need to have some kind of current limiter installed to make sure a phone isn't drawing 10-30A and blowing up.

If the cell phones (and tablets) are self regulating, then would connecting all the USB wires in parallel to one bus be adequate for this (+/-/ground bus) or would there be some kind of interference with that.

I'm not planning on connecting any of the data cables from the USB cables for various reasons (nothing to connect to on the charger for one) but IDK if these are used in any way to aid in charging.

 

Cell phones are self regulating, they charge up at the rate depending on the cells condition or depends on which resistors on the Data +/- pins at the Usb charge socket, set the maximum current of the charger.
You can set Maximum current for Android phones by shorting out D+/- pins .