PortaPow USB Power Blocker - Stops Charging, Allows Data (Single Pack)

It's mostly a phone issue. The adapter advertises its presence, and the phone wants to connect to it. If you can block the phone from connecting to the adapter, everything will be fine. If you want to go the route of using a power/data splitter, this cable does what you want: https://www.amazon.com/dp/B0CZDFGJY5 Don't be surprised by the product description; it is wrong; this cable does separate power and data. Also, many people make such a cable themselves. Finally, one can get a regular splitter and use a power blocker on one leg (e.g., https://www.amazon.com/dp/B094FYL9QT). Finally, people claim the data port is always powered, but that's not the case. After turning the car off, though, it will be powered five times for a few minutes each within a period of 2 hours. Anything that connects to the adapter during that time may keep the port awake a bit longer or cause a sleep state that is less deep and that may drain the battery a bit more than a normal sleep state.

It is a data only USB connection. It blocks the 5v power line. You can make one yourself by putting vinyl over the 5v line. Or you can buy one, for example from Amazon: https://www.amazon.com.au/PortaPow-Cased-Power-Blocker-Single/dp/B094FYL9QT (Please note I don't confined the use of Amazon, but it is a useful website to point to something you can buy)