I have an RPi B and using a USB hub need to plug into it:

  • A LogiLink Wifi nano USB, and
  • 3 USB NFC readers (3*200mA=600mA)

This should roughly add up to less than 3A:

Power for: (RPi) + (USB Wifi) + (3 USB NFC) ~ 2.5-3A

I want to use a mobile power source like a power bank, but all I see are up to 2A.


  1. Can I power the RPi through the USB with 3A or is there a limit at 2A?
  2. Are there any powerbanks that could give me 3A?


  • OT as shopping recommendation.
    – Ghanima
    Apr 29, 2015 at 8:52

2 Answers 2



The Pi B has a 1.1 amp microUSB polyfuse.

The Pi B+ and Pi2 have 2.2 amp microUSB polyfuse.


You can Google as well as me. You could always use several in parallel if you can't find a suitable single unit.


As far as, I know. Rpi B v1 draws 700mA (at max) for powering up its own processor, GPU and other peripherals. (excluding USB devices, they directly draw current from the source) Rpi 2 and B+ is said to consume even less for this part due to changes made in its power supply.

[Ref : https://learn.adafruit.com/introducing-the-raspberry-pi-model-b-plus-plus-differences-vs-model-b/power-supply]

Also, a Logilink nano wifi or any that sort of nano wifi adapter draws typically 100 - 150 mA. (Logilink adapter draws 130 mA typically. Ref : http://www.logilink.de/media/datasheets/WL0084B.pdf page 2:specs)

So even with the list of devices you want to connect, it sums up to 700mA (rpi) + 150 mA (wifi) + 600mA (3x NFC) = 1450 mA which is within the current draw limit of pi2, B+ Rpi and hence could be used with 2A power banks.

Since Joan already answered your questions correctly, i don't want to discuss it again. Hope this additional info helps.

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