Powering A 12VDC Device Via USB Port (USB-C Adapter Vs USB-A Adapter)

What will be the source of the power? USB-A only supports up to 2.5 watts and 5 volts and USB-C now supports 100 watts and 20 volts easily enough for larger devices. The power (watts) being the key factor.

Ryobi 40V 300-Watt Power Source RYI300BG

https://www.ryobitools.com/products/details/46396026651#

Based on the links provided by the OP, I think he desires a device that can be plugged into a USB-A or USB-C power source and its output is 12 volts DC. The link you provided is a device that delivers power through a USB-A Outlet, a USB-C Outlet or a 120V Wall Outlet. The OP still needs a device to fulfill his needs, i. e., getting from 5 volts to 12 volts.

The USB specs are limited to 5 volts so any USB-A adapter outputting more than that is a technically unsafe device. The sole exception is USB-C with power delivery, which can handle 5, 15, or 20V and up to 100W. So you know which way to go here. Just check the specs to ensure power delivery is supported.

Your comment "The USB specs are limited to 5 volts so any USB-A adapter outputting more than that is a technically unsafe device" is not true at all. A 5 volt USB-A port does deliver 5 volts and is further limited to 0.5 amp. In terms of power this is 2.5 watts. But there are devices made, quite reliable (Texas Instruments is one manufacturer) that can boost that 5 volts to 12 volts. But the maximum amperage now is approximately 0.2 amp. These devices are actually called "Boost converters". The Texas Instruments tech sheet is at https://www.ti.com/lit/an/snva731/snva731.pdf?ts=17028635786...

The adapter you choose will depend on what you plan to plug it into and what you plan to plug into it.

Is it to be used in a car, truck, ATV, motorcycle, e-bike, USB power bank, etc? If so, does the source have both USB A and USB C ports and what wattage will they provide? Many of these sources already have 12V electrical systems and can be tapped directly with one of these:

https://www.amazon.com/SPARKING-Cigarette-Lighter-Terminals-...

What are the current requirements of the 12V devices you plan to use? Many of these devices will easily exceed the power output of a USB A port.

To answer your question, if both USB A and USB C ports are available as a source, IMO, USB C would be a better choice.

I think the baseline USB power delivery for all formats is at 5V. Anything higher, either on the old connectors or the new, is the outcome of a handshake between the receiving device and the sourcing device. If they agree on a higher voltage that is within the capability of the sourcing device, then the power wire goes up to a higher voltage. Maximum supported current supply by the sourcing device also varies.

But if the receiving device is not smart enough to ask for it, or if the two devices don't agree on a protocol, 5V is it. There is more than one protocol out there.

Here is one rather curious device offered on Amazon which purports to speak most of the major protocols and to make an adjustable voltage output of your choice.

https://www.amazon.com/dp/B07V3L4YF3

I make no claim that this one actually works, is safe, or suitable to the original poster's needs.

Specs for the Ryobi

(1) USB-A Port, 5/9/12V 3A max. & (1) USB-C Port, 5/9/12/20V 2A max.

USB-A that's a max of 36 watts at 12V, 15 watts at 5V.

USB-C that's a max of 30 watts at 20V

The Amazon USB-C adapter Product Specification:Length:150cm/5ft, USBC Input: 15V/20V 45W USB-C Charger, Cigarette Lighter Socket Output: 12V 4.5A Max

So the Ryobi doesn't have enough power for that adapter.

The Amazon USA-A adapter Cigarette Lighter Socket Output: 8W, 12V, 0.8A Max. Please check the power of your device to make sure it is less than 8W. This cable should be used at least 5V 2A.

That would work, providing your 12V device uses less than .8A (9.6 watts).

This might work better as it can output 12V at 2A (24 watts)

https://www.amazon.com/BXIZXD-Converter-Cigarette-Telephone-...

Here is what I am thinking of trying. I mentioned in an earlier post that I am thinking of buying a Ryobi 40 volt 300-watt power source RYI300BG. I already have a number of Ryobi 40 volt batteries, so this would be a fairly simply solution for me.

I do already have a device that is a 10 amp car power supply. It isn't the exact brand name in the Amazon listing, but the specifications are the same. On the back of it lists:

AC ADAPTER

Model No: yczx1210000T

Input: AC100-240V∼50/60Hz 2.0A

Output: DC 12V⎓10A

It plugs into the home outlet, has a "power brick" in the middle and an automobile style outlet on the other end.

The Ryobi PDF list the Product Specifications as:

PRODUCT SPECIFICATIONS

Watts... 300 Watts Continuous

DC Input...40 Volts DC

AC Output ..120 Volts, 2.5 Amps

USB Output*:

USB-A...5/9/12 Volts, up to 36 Watts

USB-C...5/9/12/15/20 Volts, up to 40 Watts

Output Wave Form...Pure Sine Wave

*USB ports share internal circuitry. If USB-A is in use, USB-C will supply 5V output only.

If I understand this correctly, the Ryobi RYi300BG may provide 120 volts at 2.5 amps, which will be enough for the AC ADAPTER, which requires 100-240 volts at 2.0 amps. The adapter will then provide 12VDC at 10 amps.

https://www.amazon.com/Adapter-Cigarette-100-240V-Converter-...

https://556aa8d9de68ea9c4f29-0a8acad11a4df5016d26cc39a742984...

Also called buck-boost converters:
https://en.wikipedia.org/wiki/Buck%E2%80%93boost_converter

How long would a Ryobi 40V 6aH last using the 120 to 12 adapter with a device drawing 6 amps?

I gather that at 40V a 6 Ah battery would last an hour, but is there loss going from 40 volts DC, to 120 volts AC and then down to 12 VDC?

Also, gather that lithium-ion (protected) batteries don't run down to zero.

Under best circumstances.

By the way it isn’t certain that the device goes from 40 vDC to 120 VAC and then down to 12 VDC. It is fully conceivable that it goes from the source of 40 vDC directly to an output of 12 vDC. That in fact is more likely to avoid losses.

Keep in mind the device also needs a Ryobi battery that runs about $100 and with the battery you are about 3-1/2# weight.

That I am well aware of. I have a couple 6 AH Ryobi batteries, a 5 AH battery and a 4 AH battery.

There are three types of circuits:

A buck converter reduces voltage so the output voltage is lower than the input voltage.

A boost converter increases voltage so the output voltage is higher than the input voltage.

A buck-boost converter is a combination of a buck and boost converter. The output voltage can be higher or lower than the input voltage and can be made adjustable through appropriate design.