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We use a Raspberry Pi to display infos on a TV. The content is more or less HTML with some Animations. Currently we use a Pi2 and the power does not seem to be a problem. Recently we came up with the idea of using a Pi3 as it already provides a WLAN module. Now my question:

Does a the USB-Port of a TV supply enough power to run a Raspberry Pi 3?

  • How would we know? What power does it supply? How much does your Pi3 need? – joan Jul 15 '16 at 7:43
  • Did you try this? Did it work? – Karl Gjertsen Mar 10 '17 at 13:42
  • Just keep in mind that USB ports are limited to 500 MA. The Pi's USB ports are rated to provide up to 1500 MA total, so if you only have 500 MA coming in, you're going to be very limited as to what you can plug into USB on the Pi. Like flash drives and/or external WLAN adapters. – SDsolar Mar 28 '17 at 6:08
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According to the Raspberry Pi FAQ on Power requirements ( which can be found here --> https://www.raspberrypi.org/help/faqs/#powerReqs ):

Maximum draw from USB = 1.2A

Recommended Power Source = 2.5A

Now, according to USB specifications power output for USB works like this:

USB 1.x and 2.0 specifications provide a 5 V supply on a single wire to power connected USB devices. A unit load is defined as 100 mA in USB 2.0, and 150 mA in USB 3.0. And, a device may draw a maximum of 5 unit loads (500 mA) from a port in USB 2.0; 6 (900 mA) in USB 3.0.

Essentially, that means even if your TV provided USB3 ports that were up to spec you would not be able to deliver enough power to your Pi3.

Short Answer:

You should check your TV's manual to see exactly how much power is being output by it's USB ports, but it is very, very unlikely it will give your Pi3 enough power. I suggest using an external power source, such as a wall jack with a good power adapter (such as the RAVPower QC 3.0 30W Dual-Port Wall Charger).

good luck and happy building!

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    I'm largely on board with this answer. TVs are really unlikely to provide enough amperage to run a Pi 3 successfully. I think there's a vanishingly small possibility that somewhere out there is a TV with at least 3 x USB 3.0 sockets with a full 900mA available from each. Those could be tied (something like a 3-way Y-cable) to provide a suitable power source for a Pi 3. Testing this would give me pretty solid heebie jeebies about the long term survival of my TV. – goobering Jul 15 '16 at 10:09
  • Not to mention that virtually none of these kind of devices actually comply with the USB specs - they just supply 5V regardless, but are unlikely to be adequate. Neither does the Pi power connection comply because the data pins are not connected so it wouldn't work with a compliant port. – Milliways Jul 15 '16 at 12:11
  • An easy way to test this would of course be to just try it; on the 3 (and I think the 2 and perhaps the + models, although I have not noticed it personally), the red LED will flicker if there is insufficient current. Also, on all those models you will get a little rainbow square in the upper right corner. However, unless it stays on consistently this may be inconsequential, e.g., I've noticed it momentarily when running off a large 5V/2A power bank, but it does not actually seem to adversely affect operation. Probably not a good idea in a "production" context though. – goldilocks Jul 15 '16 at 14:26

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