- Joined Oct 21, 2015
The Pi has always been kind of selective when it comes to the power supply. They usually recommend purchasing a 2.5A PSU. I'm using two microcontrollers in my project, an L432KC nucleo which claims to be an ultra-low power MCU, and a Raspberry. I chose this AC-DC converter to power up my project. But it was a bad idea, since the board which has the converter is located 7 feet away from the Pi. So, I used a "good quality" 7 feet cable to power the Pi. It turns out that the Pi throws the "Undervoltage detected" warning. When I measure the voltage going to the Pi, I get like 4.95/4.98V. So, I'm losing about 0.05V in the wiring. I've changed the cable twice, but it remains the same. If I use the original Raspberry PSU, everything is fine. The idea is to power up the whole project with a unique power supply. So I chose the converter mentioned before to be 4A to leave a good margin for the Pi and for other minor loads which also need 5V. A better idea that I should've considered is to have 12V in the main board, and convert to 5V next to the Pi. That way, I'm transporting 12V instead of 5V, which lead to minor losses. So, what do you think the real problem is? The fact that I'm transporting 5V, or I'm still getting bad quality cable? Or worse, the converter itself? The original PSU that came with my Pi is also about 7 feet length.