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?