ESP32 and lipo fuel guage

Using Arduino Project Guidance
1

Hey guys I am using max17043 lipo fuel guage at (SparkFun LiPo Fuel Gauge - TOL-20680 - SparkFun Electronics) with esp32 on arduino. But it is not giving me good results. Some are not stable, and some are showing me less battery capacity and there is a drop of 0.1V in voltage when we compared to multimeter. I think there is a problem with i2C of esp32. I am using 21 and 22 pins and there is a library at (SparkfunTechSupport · GitHub ... /TOL-10617), which I am using and is mentioned by sparkfun.

Kindly give me suggestions.

Regards,

2

Please post your program and your wiring diagram. See this Simple Image Guide

...R

3 
#include <Wire.h>
#define MAX17043_ADDRESS 0x32
#define SOC_REGISTER 0x04
#define MODE_REGISTER 0x06
#define COMMAND_REGISTER 0xFE

void readRegister(byte startAddress, byte &MSB, byte &LSB) {

    Wire.beginTransmission(MAX17043_ADDRESS);
    Wire.write(startAddress);
    Wire.endTransmission();

    Wire.requestFrom(MAX17043_ADDRESS, 2);
    MSB = Wire.read();
    LSB = Wire.read();
}

void writeRegister(byte address, byte MSB, byte LSB) {

    Wire.beginTransmission(MAX17043_ADDRESS);
    Wire.write(address);
    Wire.write(MSB);
    Wire.write(LSB);
    Wire.endTransmission();
}

int getSoC() {

    byte MSB = 0;
    byte LSB = 0;

    readRegister(SOC_REGISTER, MSB, LSB);
    //float decimal = LSB / 256.0;
    return MSB;
}

int Battery;

int get_battery_status(void) {
  Wire.begin(21,22);
  //writeRegister(COMMAND_REGISTER, 0x00, 0x54);
  writeRegister(MODE_REGISTER, 0x40, 0x00); 
  delay(2000);
  int stateOfCharge = getSoC();
  Serial.println(stateOfCharge);
  Serial.println();
  return stateOfCharge;
}

void loop() {

  Battery = get_battery_status();
  delay(1000);

}

Regards,

ESP32.png
ESP32.png1637×740 17.5 KB

4

What I am saying is that it is not giving me results. It is not stable, means if it shows 60 %, next time it shows 58 % and after 15-20 mins it shows 51 %.

There is one idea that if I can be able to get voltage correctly through the module. So if I use a map function of arduino to map 3.5 to 4.2 into 0-100 %. Would it be correct, as I know 18650 cells can go down to 3.5V, and I can also afford to go down to 3.5V because I am using 3.3V buck converter. So I think this approach is good?

Kindly give me your expert opinion.

Regards,

5

There is "electronics" in the 18650 cell that will muck with the readings. Try an internet search on the matter.

If the library is NOT using the ESP32 A:D API to set up and make read calls to the ESP32 A:D converters, expect erratic readings.