I am using a Pi-3 with a relay board to control my gate. The gate doesnt have the facility for automation, so I have the relays, effectively pressing the buttons on a remote.

The Pi, relay board and remote are all powered by the same USB power supply. I can't use the official power supply as its too bulky for the box thats already mounted on the gate pillar. It works reliably in summer but not winter, so one of the suspects is the power supply.

Is there an actual spec/definition for voltage and current requirement of a standard Pi-3? I could then source a supply that would have enough juice for the relays as well.

I was not asking to debug the setup. I have used a Pi on my desk which was behaving erratically until I purchased a Raspberry Pi power adaptor.

The error (in Winter) used to be that it wouldnt respond to the REST calls about half the time. At those times, the gate controller always responds to the remotes that came with it. And the video camera on the same cat6 always works.

Other possibilities are

  • Loose contacts somewhere, for which I have an electrician coming next week to tighten everything from the switchboard at the house, down the driveway etc.
  • It could have been ants and cockroaches, except the box is sealed. I have not spotted anything inside the electrical utility box but I have been spraying anyway.
  • I had feared that the higher temperatures in summer may have caused the Pi inside a 3D printed box, inside a sealed box to heat up too much. But it has worked flawlessly for the past few months.
  • @Milliways, I did say one of the suspects, but have added more information. Feb 19 at 11:36

1 Answer 1


RPi publishes the power requirements for most (all?) models in their online documentation - last seen at this URL.

It doesn't sound like your "gatekeeper pi" is doing much, so I'd guess that using the figure for Typical bare-board active current consumption would put you in the ballpark wrt your RPi's current usage.

And you're going about this the right way; i.e. formulating requirements in the form of a power budget. But I do wonder about the seasonal dependence you mentioned (summer - OK, winter - not OK). But you've not disclosed any details, so I'll not speculate. Hope the data helps - let us know if you have further questions.

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