The basic question, I want a split USB cable to charge from one source, but get data from another source, and combine those to go into my phone.
My use case…
I just bought a new car that has Android Auto. Android Auto, as I’m sure most of you know, requires plugging the phone in via USB to a USB port on the car.
Granted, this port also does provide charging, BUT…
I already own a Qualcomm "QuickCharge" type car charger that plugs into the 12 volt accessory outlet (cigarette lighter socket). This is a better charger than the car’s USB port provides.
So I’d like to be able to charge from my own QuickCharge charger, but still plug in to the car USB port to use Android Auto.
I know that there are USB cables for PC accessories that provide an extra "A" plug for extra power, but the intended use of those is that both sources are still plugged into the same computer, so the USB ports share a common power source.
My concern with this is that the power source from the car’s USB port for Android Auto and the car charger accessory I have are separate power sources. Will one short out the other, or short out my phone? I’d think it would need to be a special cable that somehow isolates the power lines from side to the other.