I have a problem with my Raspberry Pi B+. First the problem was that I didn't get the keyboard or mouse to work and I have now found out that the Pi do not get enough power. When I looked on forums, they said the watt or whatever it is, should be between 4,75 and 5,25. When I check mine, it only have 3,30. This is probably enough to start the Pi, but not enough to run the USB ports. I have tried many different cables, both tried with normal cell phone charger and with iPad charger with another cable. But all of them give the same amount.

This may sound a little weird that all of them give the same amount of power, do you think I might check the power the wrong place on the Pi? I only find guides on how to check power on the normal, not the B+.

Thank you for help!

1 Answer 1


You need to carefully check the voltage. You can measure the voltage between pin 2 (5V) and pin 6 (ground). It should read around 5V.

See http://www.keytosmart.com/wp-content/uploads/2014/07/Raspberry-Pi-GPIO-Layout-Model-B-Plus.png

  • Ok thanks for a little help. When I checked on the places you said I was gonna, I shower 5,06 now, which Is enough. Dec 28, 2014 at 21:16
  • It may drop to a lower voltage as you power more kit from the Pi (e.g. plug in a USB device). If it drops below about 4.5V the Pi may reboot.
    – joan
    Dec 28, 2014 at 21:39
  • This still does not fix the problem that my keyboard and mouse don't work. Dec 29, 2014 at 10:35
  • Did you measure the voltage with the keyboard and mouse attached? If it's still around 5V then power is not your problem.
    – joan
    Dec 29, 2014 at 10:44
  • It measured the same voltage with and without keyboard and mouse. Dec 30, 2014 at 12:15

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