I have a LEGO Mindstorm EV3 hub. I want to avoid buying rechargeable batteries by supplying power through battery box pins using an external variable power supply.

Is it possible to supply power to an EV3 hub via USB?

1 Answer 1


No, the only way provided to power the EV3 is through 6 AA-batteries or the expensive rechargeable battery box. Of course some DIY solution could work, anything that provides 9V DC or thereabouts works when the voltage is applied directly to the outer battery contacts...

  • ... which means that without a buck converter, USB power won’t work as USB supplies 5V.
    – Phil B.
    Apr 4, 2021 at 13:04
  • don't know, 5V seems to low, but if the pin is pressed that the rechargeable battery unit normally presses, 7.2 V is what expected of the battery, and with batteries the voltage drops when loaded. so 5V regulated might work. Of course the EV3 will operate sluggishly... Apr 4, 2021 at 13:16
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    Here they tested with 5V, given enough amperage, attached motors even work: dexterindustries.com/ev3-current-consumption-measurement Apr 4, 2021 at 13:18
  • fettricks.blogspot.com/2017/02/… shows a home-brew solution and it sounds like you can buy some of these on Amazon.
    – chicks
    Apr 5, 2021 at 12:40
  • @chicks, unless I entirely misread the question, the idea is to forego the expensive EV3 rechargeable battery, while the link you provided shows how to create an USB charger for the EV3 battery pack. The EV3 charger (which is the same as for the power functions rechargeable battery) has an universal enough plug that an USB to that type of plug convertible should be doable to find on amazon, aliexpress and the likes,,, Apr 6, 2021 at 15:56

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