I have a variety of fast charge plugs and cables as well as an Anker power bank and a Nitecore NB10000. They support up to 3A @ 5V, 2A @ 9V and 1.5A @ 12V (i.e. 15W-18W). I believe the S10e is limited to 15W charging speed (1.67A @ 9V).

No matter what I use (even using the official Samsung plug and cable) on my S10e, the charge speed seems completely variable. I'm testing with both 3C Battery Monitor and an in-line USB power meter.

The fastest speeds I see at 5V are about 3W-5W with all power sources. Every now and then by plugging and re-plugging I can get it to switch to 9V and then it will charge at 9W. How is the charging voltage negotiated by the phone?

Another issue is every now and then the phone thinks it has moisture in the charging port (using exactly the same bone dry connector as the last 30 mins) and will be stuck like this every time I plug it in for 5 minutes. How is the moisture determined and how do I reduce the false positives?

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    The reason is simple: Samsung still uses the outdated proprietary charging methods "Qualcomm Quick Charge 2.0" respectively Samsung "Adaptiv Fast Charge" instead of using the standardized USB-PD (Power Delivery) which is included in "Qualcomm Quick Charge 4.0". – Robert Nov 19 '20 at 14:33
  • I wasn't aware that many phones had started using USB-PD. And what are the metrics for it choosing what voltage to charge at? – Turkeyphant Nov 19 '20 at 21:14
  • USB-PD uses a special communication channel between charger, cable and device to negotiate the capabilities and calculate the possible charge modes. – Robert Nov 19 '20 at 22:28
  • I meant how do QC chargers negotiate this? – Turkeyphant Nov 20 '20 at 11:35
  • As I said the method is proprietary. Not sure if it is fully documented. As far as I know they measure the resistor between certain USB connectors in the cable. And based on the result assume if the other side supports QC and which version. – Robert Nov 20 '20 at 11:38

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