Strafebogey
Member
Here's a writeup on USB-PD. http://www.usb.org/developers/powerdelivery/
This was the standard for USB PD Revision 2.0, ratified circa 2012.
And this is Revision 3.0 of USB-PD format, adding the 15V into the mix.
Nintendo AC charger is capable of charging rate that peaks at 15V 2.6A 39W. (Volts x Amps = Watts). The idea here is to get to the closest figure to the Nintendo AC charger figure while it is charging, as the AC charger powers the Switch AND charges it at a fast rate. And I found out, while playing Zelda in portable mode (undocked) at maximum brightness, maximum volume and WiFi on, that the official AC charger require 15V 1.25A to fulfil that criteria. The Switch doesn't need the full fat 15V 2.6A because it is now undocked with downclocked speeds on its CPU and GPU running at 720p only, versus upscaled 1080p with all cylinders firing (max CPU & GPU clockspeed *if required*) in docked mode.
All powerbanks can charge the Switch while playing, even the old 5V USB-A ones. My own personal requirement is "charge the Switch fast enough while playing without the battery draining faster than the powerbanks topping up the charge". With that requirement, USB-PD is required. With non USB-PD powerbanks or standard cellphone powerbanks with USB-A out ports, the limitation is on the USB-A Battery Charging 1.2 standard itself: 5V 1.5A, which 7.5W. There are other fast-charging formats like Qualcomm QC2.0/3.0 which ups the voltage and amperage to 9V and 2.4A and 3A respectively, but these formats are not recognized by the Switch, it will fall back to the 5V 1.5A charge rate. 7.5W , depending on the activity you're doing on your Switch is either barely enough to keep the battery from draining, or slowly trickle-charge the Switch battery to offset the drain from gaming. Hence why you need USB-C PD charge rate with those charging options I posted above in that table. USB-C PD works by negotiating the lowest available PD charge rate, and then "re-negotiate" a higher charge rate once it recognizes the charging equipment (charger or powerbank) is capable of a higher charge. The Switch is picky when it comes to accepting what charge rate is acceptable and what is not. From my observation here and here in this same thread, you would need 15V 1.25A (the charge rate supplied by the official Nintendo AC adapter) to sufficiently power AND top-up the charge into the Switch at a fast rate, not just to power the Switch AND stop the battery drain. The former (play and fast charge) requires either the official Nintendo AC charger or USB-PD charger with supported USB-PD 15V charge rate, while the latter (power and stop the battery drain/slow trickle charge).
TL;DR: USB-A standard powerbank and chargers may be enough to play the Switch while slowly trickle-charge it. You need USB-PD chargers/powerbanks to play and charge the Switch at a fast rate. Any fast-charging formats like QC2.-/3.0 doesn't work, your Switch will only draw 5V 1.5A maximum out of USB-A port.
Also, you mentioned the RAVPower powerbank and its 5V 3A USB-PD charging rate. My Xiaomi powerbank also has that capability, but it didnt use it, it uses the 15V charge rate instead with varying amperage between 1.0-1.25A.
From my experience logging these figures, the only charging devices I'd recommend for fast-charging the Switch would be the RAVPower 20100mAh with USB-PD (RP-PB059), RAVPower 26800mAh with USB-PD (RP-PB058-2), Xiaomi 20000mAh ZMI QB820, and the Anker PowerPort+ 5 with USB-PD. I'm interested to see the Google 18W charger, to see if that fast-charges the Switch, based on this spreadsheet, it'll be utilizing the 5V 3A and 9V 2A charge profile. I've never seen the 5V 3A and 9V 2A charge profiles work on the Switch with my charge devices I have now, so that'll be interesting to see. I hope anyone with that said charger can report back here with their findings. Need to know how fast it'll charge or does it only trickle charge. Simply drain your Switch to around 60-70% and then time the rate of charge to full versus time.
