The following conditions must be met, or else the G6 steps down power during charging and you will not get a proper QC 3.0 charge:
- battery must be below 80% capacity
- screen must be turned off
- screen saver mode must be disabled
The LG G6 has a Snapdragon 821 SoC that supports Qualcomm's Quick Charge 3.0 technology for rapid charging. However, I haven't been getting very fast charge times on my G6. I tried the stock charger/cable and even several QC-compatible 3rd party accessories. While the G6 showed a "Fast Charging" notification, it didn't seem very fast at all. It also seemed to charge faster over wireless (Qi) than with a charger and cable attached!
So I bought a QC-compatible USB multimeter to test the voltage and current the G6 was drawing during a charge. Just as I suspected, I was *not* getting a Quick Charge at all. The adapter that comes with the G6 is supposed to be able to charge at 9V/1.8A, but I couldn't see it draw anything beyond a 5V/0.5A. After much frustration and troubleshooting, I realized I had my G6 configured to run Screen Saver mode during charging. After disabling the Screen Saver, I finally saw it charge at the full 9V/1.8A!
- when the "Fast Charging" notification is displayed, it just means a QC compatible charger/cable was detected, not that it's actually charging at QC 3.0 speed.
- Screen Saver setting is located at: Settings > Display > Screen saver