I have a hard time choosing a proper USB power supply to meet my needs.
The "IQ" features which allow a higher power output are only available to compatible devices (= phones etc), right?
A regular USB port is limited to 1.5 amps, while I see the IQ boosted ports with up to 2.4 amps.
Then I see newer USB power supplies with USB-C ports that have "power delivery" up to 30 or 45 watts (or higher), but what's required on the sink's side to utilize those?
To cut it short, I'm looking for a multi port USB power supply that will also allow me to power a Pi through at least one of its ports. The Pi 3 has a power requirement of 2.5 amps and the Pi 4 has a power requirement of 3 amps and I find it silly that I have to use dedicated power supplies for those. The 2.4 amps I see on many USB chargers are borderline for the Pi3 anyway, but would a Pi3 even able to get this kind of power from the PSU or would it be limited to draw the regular 1.5 amps ? For a Pi4 only the USB-C connection would be viable, but here the same question: would a PSU not especially built for the Pi4 even allow it to draw its full requirement from the port?
Some things have really gotten more complicated over the years..... A little help would be highly appreciated. Thanks!
can somebody educate me about USB power supplies?
Re: can somebody educate me about USB power supplies?
There are many different standards for power over USB.
The various official standards (this is not an exhaustive list):
USB 2: 0.5A@5V=2.5W
USB 3: 0.9A@5V=4.5W
USB BC 1.1: 1.5A@5V=7.5W
USB BC 1.2: 5A@5W: 25W
USB-C: 3A@5V=15W
USB PD 1.0: 2A@5V=10W or 1.5A@12V=18W or 3A@12V=36W or 5A@12V=60W or 3A@20V=60W or 5A@20V=100W
USB PD 2.0+: 3A@5V=15W or 3A@9V=27W or 3A@15V=45W or 3A@20V=60W or 5A@20V=100W
USB PD 2.0 actually involves ranges of allowable currents based on source output rating rather than fixed limits, so it's not quite as simple as I listed above.
Now, add to that all the proprietary standards. Every manufacturer (that hasn't adopted USB PD) has their own standard. QualComm's QuickCharge is the most well known, with five different versions. Ther are also at least five different other proprietary charging standards based on QuickCharge, and then Oppo, Huawei, OnePlus, MediaTek, Vivo, Realme, and Infinix all have their own mostly incompatible fast charge standards.
There are also some older proprietary standards from the USB 2 days. Apple devices, for example, would allow you to pull more than 0.5A from the USB charger if certain resistor value were placed across the data lines, hence why the old iPads could charge at 1A. IIRC there were similar incompatible "faster than 0.5A" standards from Android devices too. Most of these never got marketing names.
Having said all that, what is the "PowerIQ" feature you're talking about? That is Anker's marketing name for their fast charging support in their chargers. The idea is that it can identify many of the different fast charging standards to supply the most power that the device supports. This was way more relevant back in the USB 2 days, it meant you could just plug whatever Apple or Android device into their chargers and it would go at the full speed. Nowadays they also have some voltage regulation stuff where it calculates the resistance of the cable and bumps the voltage up so that the power is at 5V by the time it reachest the device.
Anker's PowerIQ 1.0 and 2.0 technologies did not support Qualcomm QuickCharge or USB PD, so they had specific versions of products with QuickCharge or USB PD ports. Now they have PowerIQ 3.0, which supports both Qualcomm QuickCharge and USB PD, but usually only on one or two ports, with the other ports supporting PoweriQ 2.0. That is because it would be too much power if every port could go 30 or 45 or 100W or whatever.
Many of their PowerIQ 2.0 ports are limited to 2.4A. Some of them may support 3A (check the product specs). Some of their PowerIQ 3.0 ports seem limited to 2.4A at 5V.
This is kind of due to bad design on the part of the Pi. They're using non-standard amounts of power without supporting the official USB spec for using higher amounts of power. They have created a mess. But to be fair, USB power is itself a huge mess, just like everything else about the USB standard and the incompetent stewardship of the USB IF, who seem to be incable of consolidating or simplifying standards or marketing.
The various official standards (this is not an exhaustive list):
USB 2: 0.5A@5V=2.5W
USB 3: 0.9A@5V=4.5W
USB BC 1.1: 1.5A@5V=7.5W
USB BC 1.2: 5A@5W: 25W
USB-C: 3A@5V=15W
USB PD 1.0: 2A@5V=10W or 1.5A@12V=18W or 3A@12V=36W or 5A@12V=60W or 3A@20V=60W or 5A@20V=100W
USB PD 2.0+: 3A@5V=15W or 3A@9V=27W or 3A@15V=45W or 3A@20V=60W or 5A@20V=100W
USB PD 2.0 actually involves ranges of allowable currents based on source output rating rather than fixed limits, so it's not quite as simple as I listed above.
Now, add to that all the proprietary standards. Every manufacturer (that hasn't adopted USB PD) has their own standard. QualComm's QuickCharge is the most well known, with five different versions. Ther are also at least five different other proprietary charging standards based on QuickCharge, and then Oppo, Huawei, OnePlus, MediaTek, Vivo, Realme, and Infinix all have their own mostly incompatible fast charge standards.
There are also some older proprietary standards from the USB 2 days. Apple devices, for example, would allow you to pull more than 0.5A from the USB charger if certain resistor value were placed across the data lines, hence why the old iPads could charge at 1A. IIRC there were similar incompatible "faster than 0.5A" standards from Android devices too. Most of these never got marketing names.
Having said all that, what is the "PowerIQ" feature you're talking about? That is Anker's marketing name for their fast charging support in their chargers. The idea is that it can identify many of the different fast charging standards to supply the most power that the device supports. This was way more relevant back in the USB 2 days, it meant you could just plug whatever Apple or Android device into their chargers and it would go at the full speed. Nowadays they also have some voltage regulation stuff where it calculates the resistance of the cable and bumps the voltage up so that the power is at 5V by the time it reachest the device.
Anker's PowerIQ 1.0 and 2.0 technologies did not support Qualcomm QuickCharge or USB PD, so they had specific versions of products with QuickCharge or USB PD ports. Now they have PowerIQ 3.0, which supports both Qualcomm QuickCharge and USB PD, but usually only on one or two ports, with the other ports supporting PoweriQ 2.0. That is because it would be too much power if every port could go 30 or 45 or 100W or whatever.
Many of their PowerIQ 2.0 ports are limited to 2.4A. Some of them may support 3A (check the product specs). Some of their PowerIQ 3.0 ports seem limited to 2.4A at 5V.
This is kind of due to bad design on the part of the Pi. They're using non-standard amounts of power without supporting the official USB spec for using higher amounts of power. They have created a mess. But to be fair, USB power is itself a huge mess, just like everything else about the USB standard and the incompetent stewardship of the USB IF, who seem to be incable of consolidating or simplifying standards or marketing.
Re: can somebody educate me about USB power supplies?
You'll want to make sure you get the revised model of the Pi4 if you intend to power it from a non-dedicated power supply. The first batch came with an improperly implemented USB-C PD circuit that is incompatible with certain USB-C cables.
https://hackaday.com/2020/02/23/raspber ... power-fix/
The high current draw may cause voltage drops when using USB multi-port chargers so you'll also want some way to monitor USB voltage while the Pi is running.
https://hackaday.com/2020/02/23/raspber ... power-fix/
The high current draw may cause voltage drops when using USB multi-port chargers so you'll also want some way to monitor USB voltage while the Pi is running.