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Is it a bad idea to power a Pi 2,3, or zero from a mobile phone power pack?

I understand that Pi power consumption is as follows,

*** Idle ***
Raspberry Pi 2 B:  420mA
Raspberry Pi B+:   230-240mA
Raspberry Pi B:    320-330mA
Raspberry Pi A+:   180-240mA
Raspberry Pi A:    120-140mA
Raspberry Pi Zero: 60-70mA
Raspberry Pi 3 B:  280-320mA

*** Under Load/Max ***
Raspberry Pi 2 B:  450-650mA
Rasbperry Pi B+:   300-600mA
Raspberry Pi B:    380-450mA
Raspberry Pi A+:   200-300mA
Raspberry Pi A:    170-300mA
Raspberry Pi Zero: 120-150mA
Raspberry Pi 3 B:  500-800mA

The power pack I have has ratings as follows,

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If the output from the pack is 1000mA and for example the Pi zero has a max of 150mA would this power pack be too much for the Pi zero or would the Pi only pull from the power pack what ever power it needed?

So this power pack would run a pi-zero for over 14 hours or 22000/150.

I am thinking of running it headless.

4 Answers 4

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If the output from the pack is 1000mA and for example the Pi zero has a max of 150mA would this power pack be too much for the Pi zero or would the Pi only pull from the power pack what ever power it needed?

The figures are the maximum rating for the supply. Don't expect it to work if you hook up a load that exceeds the supply. It is not a problem when the load is less than the capability of the supply.

For the phone packs with the USB ports, I wouldn't worry about anything getting damaged (some mobile phones will draw much more and they need to protect against that), but I might fear that the max current is optimistic. It could be that the inexpensive ones will provide low voltage at the high end of the current spec. You could end up with a misbehaving system if it draws too much.

For a zero, I'd certainly plug it in and try it (and make sure you have an image backup in case the filesystem gets corrupted when you run it to empty without shutting it down first).

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Current can not forced, it is drawn by the circuitry.

If the Rpi Zero is rated for 150mA, and you have a power supply that is rated 2000mA all that will happen is that the Rpi will only draw 150mA from the supply.

Voltage on the other hand will cause damage, and you can force too much through the circuitry by using a power supply that has voltage higher than specified required input which in this case is 5.1v.

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I have succesfully used powerbanks in situations where the Pi would need to keep running for a few hours after the power went out. Just check whether your powerbank can charge and provide power at the same time, and you can even use them as a backup battery. I have used a powerbank to power Pi's for a couple of years now without any issue.

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  • Wow that is a great possibility. Not sure if it can charge and provide power at the same time. I suppose the only thing to do is to try it.
    – ofey
    Oct 7, 2017 at 9:25
  • Unfortunately my power pack doesn't do both, but good to know there are some available that can.
    – ofey
    Oct 7, 2017 at 9:55
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Raspberry Pi UPS link here Should be fine as long as the Pi isn't powering other USB devices.

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