ESP32 with a car battery

Other Hardware Motors, Mechanics, Power and CNC
1

Hello.
I would like to use a car batterie (12V) for the power of my ESP32 LilyGo.
I know how to reduce the voltage (using a voltage divider bridge - with 2 resistance in serie 22ohm and 10ohm ) but is it enough ?
Or do I need to user other electronic equipment ?

2

A voltage divider cannot be used for the power line. You have to use an electronic voltage steep-down module.

3

Using resistive dividers, in addition to having a lot of unnecessary consumption, is not a good solution.

You can use 12V to 5V regulators, but in general they are also not very efficient in terms of consumption.

It is best to use step down modules that reduce the voltage from 12V to 5V,

PS: Like this
https://www.amazon.com/DROK-Mini-Buck-Converter-Step/dp/B096RC71DC?th=1

4

By the way, check your calculator, such voltage divider give you a 3.75v that a quite much for esp32

5

OK. Thanks for your input. I will order one. But... just for my understanding, why a voltage divider bridge is not enought ?
Cheers.

6

OK. Thanks for your input. I will order one. But... just for my understanding.... why a voltage divider bridge is not enought ?
Cheers.

7

Because divider output voltage depends on load consumption.
By connecting different devices to your ESP32 board - LEDs, sensors, modules - you can change its consumption several times, while the voltage on the divider will change

1 Like
8

I disagree you do not have an idea of the basic concept of a resistor divider. Do yourself a favor and read some tutorials on basic electronics, Study Buck, Boost and SEPIC converters. Download the ohm's law calculator and play with your divider you can also get a resistor divider calculator.

9

It is always better to use the voltage regulator instead of voltage divider which provide stable output voltage, protect from damage occur by voltage fluctuation.

10

OK. Understood.
Regards.
CH

11

Many thanks.

12

Hi. I have already (2 years ago) order this one : CC/CV Max 5A DC-DC Abati eur Buck Conseil de Charge XL4015 Chargeur de Batterie au Lithium Convertisseur Tech DC 0.8-30V à 5-32V Buck - AliExpress

Is it OK ?

13

No. That is a CC/CV charger for Lithium batteries and it is designed to shut down its output when charging is complete. Depending upon how it sees your ESP, it may start in CC (constant current) mode and limit both the voltage and current to your device below the device requirements. Another possibility is it sees the device as either fully charged or not charging correctly. Either of these will result in the charging system output shutting down and not supplying any power to your device.

14

Understood. Thanks for your clear explanation.

15

Hi. Sorry to bother you again, but I'm not an expert on electronic matters. May I raise 2 questions ?

  1. I would like to order an board that is "more simple" that will be easier for me to configure.
    This on seems to be more "simple" : Hailege 5pcs 3A DC-DC 2596S Step Down Buck Power Module Power Regulator Adjustable Power Convert Module 24V to 12V 5V 3V : Amazon.fr: Commerce, Industrie et Science

Do you agree with me that it should be OK ?

  1. 3A for an ESP32 LilYGo Lora is OK , (not too much) ?

Thanks in advance for your answer.
CH

16

Yes, adjust output to 5V.

17

Yes, the 5V type.

18

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