My project consist of creating a mini video game console with a couple of emulators from different old retro game consoles. The machine has a Raspberry Pi 3 model B and a 2.5" external HDD (USB 3.0) connected to the Pi via regular USB. The software used is called "Retropie".

I powered the whole thing using a AC/DC 5V 2A power supply and, while everything runs OK, I had some issues while testing Play Station 1 games (which require more hard drive usage). Googling around I read that could be an amperage problem so I bought a 5V 3A power supply (which I attached a female USB connector since it didn't have any), and I had more issues than before: the Pi tells me every time there is an undervoltage issue by displaying a little thunderbolt icon on the software I am using (retropie). With the last power supply not only did the icon display every time but it also took a lot more time to boot up.

How can I make sure that there is enough power for the HDD all the time?

  • 1
    throwing a higher amp charger at the problem will not automatically fix the problem. Per the USB 2.0 spec, a USB port only needs to provide 0.5 Amps. So despite having more Amperage available, it will not by default supply it to the hard drive. You have two choices, 1) use a powered USB hub to connect the drive to your Pi or, 2) you can modify the /boot/config.txt file to increase the current supplied to the USB port (by adding max_usb_current = 1). May 18, 2017 at 12:35
  • Modifing the amp output for the usb on the pi did the trick! Thank you!
    – Spielbergo
    May 18, 2017 at 18:57

2 Answers 2


USB 3 devices that don't have a separate power supply where there USB 2 counterparts do have one need more amps than you RPi 1/2/3 can supply safely. In most cases an USB 2 port on a computer will not power a eHDD, because it was designed to provide 0.5A (note that a lot of motherboard designers have opted to provide more than 0.5A), a USB 3 port is designed to provide a minimum of 0.8A. My solution would be a powered USB 3 hub (take one of a good quality) and use it to power your RPi and it will correctly power your eHDD. The best thing you can do is avoiding the use of USB 3 devices other than simple flash-memory on the RPi's.

  • A powered USB 3 hub may not be sufficient. The better solution would be to use the hub only to power the HDD. May 19, 2017 at 13:05
  • Most good powered USB 3 hubs comply whiff the battery charging standard and so they will be sufficient to power your RPi.
    – Mat_64
    May 20, 2017 at 13:15

I have had good results with the WD PiDrive Cable http://wdlabs.wd.com/products/cable-pidrive/. It will not connect to all hard drives as it has a funny connector. It is a Y type cable that your power supply cable plugs into it and it powers the Hard Drive and the PI in parallel with the USB cable also.



Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.