How to get fast charging diagnostics information I want to find out what type of Fast Charging is supported by different combinations of Android device, cable and charger.

I have a variety of devices, from different manufacturers and with different Android versions; a selection of USB chargers with different rated voltage and current outputs; and a miscellany of USB cables and adaptors.  I want to work out which ones to use to get the fastest charge rate for each.  Also, I would like to be able to decide which new chargers/powerbanks to buy for best compatibility.  I understand that there are various different methods of Fast Charging (as explained at battery - How does fast charging work?).  Unfortunately, the documentation supplied with my devices is pretty sparse.

Is there some way (an app, diagnostic screen, API call, etc.) that I can get my devices to tell me some of the following:


Which fast charging standard(s) does the Android device support (e.g. Qualcom Quick Charge 2.0, USB Power Delivery 3.0, etc.)?
Which fast charging standard(s) does the connected charger support?
What standard is actually in use?


Alternatively, are there any good rules for inferring what standard is in use from the current being drawn?

I have seen various apps that display the charging current, but the ones I have tried haven't displayed information about the standard being used.

This question is similar to How do I know that a charger is a Turbo Charger for my Moto, but I want to know about the supported standards, not just "am I fast charging?".  Also, I would like some way of interrogating the hardware, rather than having to google the specs for each device and charger separately.  For clarity, I am only interested in wired USB charging, not wireless.
AFAIK, no, it's not possible. Reasons :


Android only tells you the levels at which the device is considered to be charging normally or fast charging. This was based initially on current and now on power in watts. See Andrew's answer and also my answer there.
There are at least 5 proprietary fast charging technologies and obviously all details are not made public. Recognizing the device, the type of charging is a complex interplay between battery, charger and OS and is charging technology specific (whether current or voltage or a combination of both is used to charge fast) . The device may /may not recognize and notify if a different technology charger is used.
Even within the same technology, there can be variations; for example Qualcomm 2.0 increases current while Qualcomm 3.0 increases power (product of current and voltage).


IMO your mission would need you to have rooted devices, see the levels at which charging normally or rapidly is determined (first bullet point) and determine, if you can, from the system files what type of technology is used. It's easier to Google. To the best of my knowledge, there is no app that can help ( I may be wrong here, haven't updated myself)