[SOLVED] Power supply for Raspberry Pi 4 ?

[1cherokee79]

I had bought me a power supply for the Raspberry Pi 4 that i have fixed up to play MP3.
But the power supply here https://www.amazon.com/dp/B07TYQRXTK?psc=1&ref=ppx_yo2ov_dt_b_product_details is too short at only 5ft long.
Where my player is located i need an extension. I once chat to someone on Amazon.com about that issue and the told me these would work https://www.amazon.com/gp/product/B07KK9QXPM/ref=ppx_od_dt_b_asin_title_s01?ie=UTF8&psc=1 but when i got it, it did work, but on the monitor while playing my MP3, i started noticing the yellow lightening bolt in the top right corner flashing ?

 

[lvt]

You should have tried a power cord extension instead of USB cable extension (cheaper and more reliable).

What the yellow light means when it's flashing?

 

[OldSurferDude]

The yellow lightning bolt indicates that the power supply is not providing sufficient voltage.

Off the top of my head, this happens because the long cord has higher resistance than the short cord. Voltage (V) = Current (I) * Resistance (R) (V=IR). The voltage at the power supply is fine, but the current (I) is 2 to 3 amperes. Assuming the resistance 0.1 ohms (20 AWG wire and 10ft long) and the voltage of the power supply is 5V and the RPi is drawing 3A, The wire takes down the voltage by 0.3V, So the RPi is getting a voltage of 4.7V, less than the required 4.75V

You can read more at this site

 

[lvt]

The yellow lightning bolt indicates that the power supply is not providing sufficient voltage.

Off the top of my head, this happens because the long cord has higher resistance than the short cord. Voltage (V) = Current (I) * Resistance (R) (V=IR). The voltage at the power supply is fine, but the current (I) is 2 to 3 amperes. Assuming the resistance 0.1 ohms (20 AWG wire and 10ft long) and the voltage of the power supply is 5V and the RPi is drawing 3A, The wire takes down the voltage by 0.3V, So the RPi is getting a voltage of 4.7V, less than the required 4.75V

You can read more at this site

If so this simple power cord extension is enough to fix the problem.

 

[Alex0007]

The problem with most USB cables is the conductors are so thin that over distance the voltage drop is significant enough to cause the low voltage alarm. If you are confident. the Red and black wires in the USB cable are the 5 volt and 0 Volt. You can get a thicker cable and replace the cable between the two connectors, it i low voltage. This does not mean you don't need to put insulation over the joints in the cable.