I was wiring in a charge only USB port in my car today and found out that cutting the data lines limits the charge rate to a uselessly low rate. You need to tie the data lines together to put it in usb bc1.2 mode. Or 2.7 v on each line for 2.4 a iPhone charge or other modes. It isn’t simple. Simpler than Bluetooth, but not “hook up ground and 5v” simple.
iOS devices will outright not charge if there’s just 5V on the port. Even the lowest charging current requires some sort of resistor arrangement.
Fortunately it seems like bridging the two data lines (essentially a 0 ohm resistor) is what’s needed to allow high-current charging (I think it’s 2 amps), so as long as your supply can withstand it (which pretty much every single device can, given that it’s tied to its own 5V rail which can supply many amps) you can just bridge the two pins together. Worst case scenario the overcurrent protection on the port will protect the source device.
