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I want to power my nodemcu module with 3.3 V.

Does powering it with 3.3 V also power USB-UART module?

If so I do not want this as it eats the battery.

enter image description here

  • What is the version of you NodeMCU? – Bence Kaulics Jul 24 '18 at 11:21
  • @BenceKaulics 2nd generation / v1.0 / V2 – A C Sreedhar Reddy Jul 24 '18 at 11:24
  • if you want low power, you really need to get away from modules and especially devkits. – dandavis Jul 26 '18 at 18:32
3

Yes, the schematic of the v1.0 NodeMCU shows that the 3.3 V bus is directly connected to the CP2102 chip.

enter image description here

You have two possibilities:

  1. Cut the 3.3 V trace on the PCB before the CP2102 chip. Not recommended as you will disable your programming interface and would be hard to restore it.
  2. The reset pin (RST) pin of the CP2102 is floating, you can try to pull it down to GND and keep the chip in reset, to see if that makes it any better.
  • But in deepsleep mode when the current is measured with a multimeter it is 0.000 – A C Sreedhar Reddy Jul 24 '18 at 12:04
  • Are you sure that you are measuring it correctly? 0.000 seems strange also it means nothing without units. – Bence Kaulics Jul 24 '18 at 12:32
  • Sorry it is showing 0.00 – A C Sreedhar Reddy Jul 24 '18 at 13:18
  • And is it kA, A, or uA it matters a lot? 0.00 without SI unit is just a number and nothing else. – Bence Kaulics Jul 24 '18 at 13:21
  • 0.00 amperes using multimeter – A C Sreedhar Reddy Jul 24 '18 at 13:22

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