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I want to power an ESP32 with a 3.7V LiPo battery. There's a LED matrix of 64 WS2812 LEDs attached to the ESP32. I learned that I need a buck boost converter to power the microcontroller as it needs a 5V power input. The boost converter delivers that when there is no matrix attached. However if the matrix is attached it only receives about 2.7V. Turning the potentiometer on the boost converter changes nothing in this case. What is the reason for this? I am sorry if this question seems basic to you. I am an beginner with electronics.

Here is a rather hideous scetch of the connections. I hope this is okay: enter image description here

This is the buck converter I used: https://www.amazon.de/gp/product/B079H3YD8V/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

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    the converter is probably not able to supply required current to power the LEDs
    – jsotola
    Mar 11, 2021 at 2:01
  • Obviously @jsotola is right, 20x3 = 60mA each led group X 64 means almost 4 amps. way above 2 amps advertised by the seller which are never true. Even with a good boost converter, is your battery capable of supplying 5.5 amps required at the boost converter input?
    – Dorian
    Mar 11, 2021 at 9:43

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The way you have it set up is fine if you aren't going to light up all the LEDs at full brightness. And if you do, you're not going to break your ESP32 Dev Board the way you have it set up in your diagram (since you are not running the power THROUGH the board). The LiPo battery probably has its own little regulator on it to prevent it from being damaged.

Check your dev board specifications on how much power you actually need to supply to the Vin pin. The ESP32 chip operates between 2.3 and 3.6 volts (3.3 recommended). Your dev board regulates the 5v to provide that amount to the chip.

Most likely, your dev board will run fine on the 3.7V provided by your LiPo without the buck-boost. I use a similar setup (without a buck-boost) to demo little projects to friends. I use a ESP32U-01 dev board from EZSBC, a 64 LED Matrix from Adafruit, and a 3.7v LiPo battery.

Depending on how many LEDs are lit (and what color), you shouldn't expect the battery to last very long. And the overall brightness of your led matrix will be limited.

If you are using the FastLED Animation Library, I would recommend setting a power limit using set_max_power_in_milliwatts function and limiting it to 1500mW for starters. Again, if you are not drawing power THROUGH the ESP32 board, you're fine.

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  • By the way, if you really want 5v power, which will power your your LEDs better, I would suggest using a standard mobile phone battery pack, like an Anker PowerCore 10000. But DO NOT plug the USB directly into your dev board! Take an old USB cable, cut the end off and create a pigtail with the power wires to plug into the same Vin and LED cables you are using in your diagram.
    – DelugeIA
    Mar 25, 2021 at 20:50

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