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I recently blew up the 5V 2A PSU that came with my Pi. Since then, I am using my phone's charger, 5v 1A to run my Pi. And while it runs fine most of the time, I see the undervoltage warning, while it boots up, and also when I am running my Image processing algorithm, which I made as a part of my project.(heavy CPU/GPU usage at that time)

I tried running the Pi of batteries, made a 7.8V pack connected it to a 5V 3A UBEC. I still get the undervolt warning.

I tried another 5V 2A adapter but that also gave me the undervolt warning.

What I'm worried about is, can being undervolt decrease the Pi's performance? If yes, how do I counteract it? I increase the current or the voltage?

Current Pi Setup- Raspberry Pi 3 => 1 Arduino UNO connected Via USB, Standard USB Keyboard and Mouse, 1 Raspberry Pi camera module, output to HDMI display at 720p.

Final Pi Setup (for my project) - Raspberry Pi 3 => 1 Arduino UNO connected, 1 Raspberry Pi camera module connected, VNC Server running in the background. At least 1 device accessing the terminal via SSH, Image Processing script running continuously

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  • So.... Before your power supply blew up, you didn't get under voltage? Now with any other power supply you get the warning. Sounds like maybe something got damaged on the Pi during "blow up" ? :( Performance may decrease but only because undervoltage flag sets the CPU to run slower to prevent brown out (but I am assuming here no actual proof of that) It may as well run without problem. Do a benchmark and find out.
    – Piotr Kula
    Jun 16, 2016 at 6:53
  • @ppumkin Actually my PSU was kinda loose in the socket I put it in, and all of a sudden it went BAM! I pulled it out asap and was half afraid that my Pi was gone. Nevertheless, it worked with other supplies which was a relief. Now I'm not sure whether or not I got the undervolt warning before my PSU blew up, I never noticed( Maybe bcz it wasn't there before).
    – YaddyVirus
    Jun 16, 2016 at 7:05
  • Wow... wondering why it blew because of loose socket? Do you have another Pi? Long shot but maybe try another SD card and fresh install see if it still does that.
    – Piotr Kula
    Jun 16, 2016 at 7:07
  • @ppumkin Anyways since my current PSU is a 5V 1A, the undervolt warning makes sense as not only it is less than what's required, but also there is heavy load on the CPU/GPU. As for my battery pack, it gives 5.05V with a 5V 3A UBEC. Now in case the Pi needs more than 5.05V or 3A while trying to run my script, the undervolt warning again makes sense. However the undervolt warning is more common coming up when the Pi is idle than my phone charger, in which, the undervolt warning rarely comes during normal use of the Pi.
    – YaddyVirus
    Jun 16, 2016 at 7:08
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    Also the reason why people say you need a good voltage, is because fluctuations in voltage causes major fluctuations in Wattage. (ohms law) This is why cheap power supplies tend to cause problems because the voltage is allover the place (using a oscilloscope) - Major fluctuations can cause adverse affects on the Pi.
    – Piotr Kula
    Jun 16, 2016 at 7:17

1 Answer 1

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Yes, Current it was.

My Pi was running undervolt only because the power drawn from the source was lowering the voltage. I modified my battery pack, and using a total of three cells, I first connected 2 in parallel, to pump up the amps and then added the third in series, to increase voltage. Again ran the pack through the same 5V 3A UBEC and guess what, undervolt warning was gone.

As for my original question. Yes, being undervolt reduces the Pi's performance as when the undervolt warning was gone, my average framerate rose from ~65 to ~85. A performance boost of 130.769 % , or 25 FPS(trying not to be fancy :P)

Thanks for all the help in the comments!!

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  • This pack configuration is not optimal because the third cell will drain twice as quickly. You should use a symmetrical arrangement, like 2 groups of 2 cells in parallel, with the groups in series.
    – user253751
    Jun 18 at 18:03

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