I'm using a car-style USB charger with a 12V port, but it often exceeds my maximum draw of 18W when it fast charges my phone. I'm considering options to limit the charger's output to stay under this limit. Is there a way to disable fast charging capabilities? I thought about blocking the data pins on the USB A port. Would that just default it to 5V/1A? Is this achievable with basic soldering tools or do I need to find another solution?
2 Answers
Blocking the data pins is a solid approach! Fast charging relies on negotiation between the charger and the device, so if you can cut that off, your phone should revert to standard charging. It sounds like finding a data blocker cable might be the most straightforward way to achieve this without modifying your existing hardware. Plus, they're pretty easy to find online, so you won't have to stress about soldering!
You can definitely stop your phone from fast charging by using a USB data blocker. Just covering the two middle pins on the USB-A plug should prevent fast charge negotiation, which means it’ll only deliver 5V/1A as you suspected. There are even ready-made products like data blocker adapters available that can make this easier for you to implement without needing to solder anything.