[LG V20 Questions & Answers] br0adband:
The V20 does not support QuickCharge 3.0, that needs to be clear from the start because it causes a lot of confusion. The Snapdragon 820 does have support for the QC 3.0 standard, but LG chose for some reason NOT to support it. What the V20 does support is USB-PD aka Power Delivery which is similar to QC 3.0 in how it operates but it is NOT QC 3.0 (but the V20 does support QC 2.0 without issues with the stock charger).

USB-PD works like QC 3.0 in the sense that it does the charging in a different way that keeps the cells cooler during the charging process and doesn't cause the heat buildup that QC 2.0 causes. The factory LG V20 charger supports QC 2.0 and if you go into the hidden menu (*#546368*<3-digit model number>#, might not work on every variant) and then SVC Menu - Battery Test - Battery Info - select the Enable Log button - check the box for Battery Log Save On/Off and it will then show the relevant info. Once you see the information display, plug in whatever charger you wish and then wait and see what it shows for High Voltage parameter.

If it's QuickCharge it will show the version being used - the stock V20 charger shows me QC2 so that's QuickCharge 2.0. I have a Samsung QC 3.0 compatible charger and when that's attached it shows USB-DCP which from what I understand is Samsung's modified variant of USB-PD but that could be wrong. I did some quick research and found this so it could be limiting the charging to 1.5A which is perfectly fine with me):

That was taken from this page:

https://www.maximintegrated.com/en/app-notes/index.mvp/id/4803

My V20, using the stock Samsung 2A charger that I always use (because I don't like to quick charge my batteries, I don't trust it in any form and I still think it's damaging the cells but that's my own personal opinion on quick charging overall), can go from 15% to 85% (I use AccuBattery set to 85% and it alerts me when it hits that point so I can unplug, this increases the overall lifespan of the cell I'm using as measured in years not per-charge) in about 55 minutes to 1 hour depending on whether I'm still using the device or letting it charge screen off. That's using a plain old vanilla 2 amp capable charger and when I check the charging current sometimes it'll actually show 2.2 amps (2200+ miliamps) so I'm perfectly happy with that situation.

I've read reports from owners of Pixel USB chargers and when they use them with their V20 smartphones and look at the battery info in the hidden menu it will show USB-PD so I might have to get one of those sometime and see how it goes.

Suffice to say, 55 minutes for a 15% to 85% charge for me is fast enough and the battery still stays pretty cool overall. USB-PD is probably the best tech we'll be able to make use of with the V20. I've read that the V30 does fully support QC 3.0 without issues and the the stock V30 charger is QC 3.0 compliant. The new V40 is QC 4.0 ready but I don't know at this moment whether or not the actual stock charger handles it but again, the QC 4.0 support is handled by the SoC and it remains to be seen if LG allows it or forces it to QC 3.0/USB-PD operation. Guess I need to do some research into that aspect of the V40 too.