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I've got a Pi 2 B+ and I plan on using one of those portable battery-powered phone chargers to power it.

I'd like to get about 8 hours of continuous power. I'll also be powering a 5-inch LCD and a wireless keyboard receiver. Any idea how much power this Pi would be using over an 8 hour period?

Estimates would be fine, I'm just looking for a general idea of the power consumption.

Ghanima
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Tarc
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    This link provides a pretty good estimation : http://raspi.tv/2014/how-much-less-power-does-the-raspberry-pi-b-use-than-the-old-model-b – dhruvvyas90 Dec 11 '15 at 04:01
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    One annoying thing to keep in mind with phone chargers is that most of them have a shutoff if the current draw dips too low - they expect a pretty continuous power draw when charging a phone and sometimes will cut off even with short-term dips in current draw. I've run into this with both pi and arduino projects. – T3am5hark Dec 11 '15 at 17:24

4 Answers4

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As two previous answers already give some references for the power consumption of different models of the Pi and various load cases, I would like to add a note on the amount of energy a portable "power-bank" will have to provide over an 8 hour period.

Assuming the bank can provide its power at a constant 5V level. It's really as simple as this:

E = I * t * SF

with I being the current drawn by the Pi and the additional peripherals (measure this for the real thing), t the duration (8 hours), and SF a safety factor to ease your mind and accommodate for aging of the battery. So as an example:

E = 800 mA * 8 h * 1.2 = 7680 mAh.

On a nit-picking side note: technically it should read not power but energy in "how much power this Pi would be using over an 8 hour period". The integral of power over time defines the work performed - which is an amount of energy.
Ghanima
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I found a nice overview at Raspi.TV:

power consumption

If you have a Raspberry Pi 2, which is idling it will use 5V * 230mA = 1.15 Watt

If you would like to watch mainly a Video you will get 5V * 290mA = 1.45 Watt

But if you are using a phone battery bank, they typically say how many mAh they can provide.

S.Spieker
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According to this, a Pi 2B will draw at least 420mA, but this might help you reduce power draw.

As you can see, the 2B draws way more power than the other models, especially the Zero, so maybe you might want use a different model.

Kirby
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Not exactly same as your case, but my setup has a Pi 4 and a 7" HDMI display, and it draws about 700mA from a 12,6V li-po pack (8,82W).

Considering that I am passing the batteries on a UPS (battery charging and buck/boost)to 15V and also have another buck (LM2576) from 15V to 5V - and considering the efficiency of each to be 85% - you can expect the PI 4 and 7" screen to consume around 6,37W, so 1,28A in 5V.

Also, as others have pointed most of the current power banks have an "auto power off" scheme that shuts the power when is is too low, so sometimes a USB power bank like those may not be the best fit for you. I am leaving the link to the UPS I am using, it charges the battery and outputs 4-23V in up to 5A: https://pt.aliexpress.com/item/32783727347.html

Clóvis Fritzen
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  • A lot of your posts appear to be promoting items found on AliExpress. – Greenonline Jan 17 '23 at 23:25
  • They are actually items I found and that work for the question being asked. None of the products are sold by me, I am not a seller, just a guy who found interesting gear and wants to share. That's all – Clóvis Fritzen Jan 18 '23 at 11:57