**Member Since: 8 years (?) starting with a Defy XT
**Phone: New Pixel 4a replacing a Moto G1
**Plan: My Choice with 1G data
My Pixel 4a came with a USB C cable and charger. I seems to charge very fast. Using a magnifying glass on the charger, I noted the output voltages are listed as the usual 5 volts DC (at 3.0 amps) characteristic of all earlier USB connectors but it also listed an output of 9 volts DC (at 2.0 amps). My next stop was Wikipedia to examine the standard pinout of the USB C cable, but that gave no clue as to voltages that might appear on some of the 12 pins on each side of the connector which allow it to be plugged into a device in an “any side up” orientation.
So here are my questions for anyone (no guessing allowed) who has authoritative answers:
Does Google use one of the auxiliary pins on the USB C connector to permit a faster charge rate using 9 volts DC?
If I use one of my older USB chargers that have a USB A connector into which I can connect a patch cable with a USB A on one end and a USB C on the other end, can I use it on the Pixel 4a without fear of damaging the phone?
If the answer to question (1) is no, will I see the same apparent fast charge rate on my new phone if I have an older charger capable of delivering a 3.0 amps output at 5 volts if it can be fitted with a cable having a USB Type A connector on one end and a USB C connector on the other end? (Note: A quick check of several “old” chargers for previous cellphones with chargers having a USB Type A jack for output show current capacities of 800ma to 1.5 amps. Only a charger for a Samsung Tablet shows a current output of 2 amps (5 volts @ 2 amps=10 watts). The Samsung Tablet also seems to charge quickly. So perhaps the 15 watts (5 volts @ 3.0 amps) of my Pixel 4a charger is what is giving these delightfully quick charging results.)
It seems to me that I saw in some Pixel 4a literature a 18w charging capability is available. That is curiously familiar since 9 volts @ 2 amps produces – 18 watts!! Is Google using some of those “extra” pins in the USB C connector to use the connector in a proprietary way to get a fast charge?