I have used these to successfully power my RPi5 with NVMe SSD: ?
$13 ? YIPIN HEXHA 10-32V DC in to 5.2V 6A dual USB type C outputs ?
$10 Klnuoxj 8-32V to 5V. 5A. USB-C PD Step Down Converter. 95% effeciency, Waterproof.?
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The RPi5 will run fine with 3A or more at 5V PD, if there is no USB load, but a 5 ampere or more 5.2 V supply is necessary to draw the maximum 1.6A from the USB ports.? ??
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Normally, the RPi5 is configured to use USB-C Power Delivery (PD) protocol, to negotiate 5A from the PD capable Raspberry Pi 5.1 volt mains power adapter,?
and shuts down if it fails to get PD acknowledgement that 5 A is available.?
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However, if you edit and add the following lines to the end of file /boot/firmware/config.txt :?
? usb_max_current_enable=1?
This will force the RPi5 to ignore the Power delivery communication, and assume the power supply is capable of delivering 5A.
This change allows many 12 volt to 5.2 volt USB power converters and automotive USB outlets to power the RPi5.?
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The USB-C Power Delivery 3.0 standard specifies a 5 volts at 3.0 amperes; ?however, the PD protocol allows for requesting higher current. ?
The Raspberry Pi 5 wall wart acknowledges a PD request for 5 amperes.?
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The RPi5 will deliver an "Under-voltage" warning when operating below 4.63 volts, as measured at GPIO pin 2 or 4.?
?In Raspian OS, a lightning bolt appears in the upper right corner of the display.
?In Raspberry Pi OS, a "Low voltage warning" text appears in the display upper right corner.?
?"Under-voltage detected!" is also logged in dmesg for each occurrence.?
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Often the cause is too much voltage drop in a poor USB power cable.?
I have taken apart flimsy cables where the wires were not soldered, and relied upon the rubber over-molding to hold the wires in contact with the connector pins.??
USE A BEEFY USB CHARGING CABLE designed to charge smart phones and laptop fast charging:?
? $5 USB A to C ??
? $6 USB-C to C ??
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To see what the RPi5 measures on the 5V input, enter on the terminal:?
? ?vcgencmd pmic_read_adc | grep EXT5V_V
You will be surprised at the voltage drop in most USB supply cables.?
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With all USB loads attached, enter in the terminal:?
? dmesg | grep voltage?
To see if "Under-voltage" is occurring.?
N0YWB