I would like to build a charging station for EV3 with rechargeable battery (45501).

Does the transformer (45517) give a simple stable dc voltage (power supply)? Or does it provide a controlled voltage / current depending on the charge with charging a method (CC-CV or other)? What is the charging method?

In other words: the charging intelligence is in the rechargeable battery or in the transformer?

1 Answer 1


The charging circuit is in the battery, so any 10V, 700mA DC power supply should work. The circuit driven by a MP26123 chip.

The battery schematic is available from the EV3 Hardware Developer Kit on the MINDSTORMS download page for anyone who wants to confirm this.

  • Thanks a lot David for your very completed answer.
    – Jean
    Commented Dec 13, 2021 at 20:17
  • Don't forget to mark this as the correct answer if you find this helpful (it helps other people find the answer too). Commented Dec 13, 2021 at 21:13

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