Reading 7 external voltages

[bobbych]

Hi

I'm extremely new to this and like most I try to learn by playing with other peoples code.

I want to read 7 voltages from an external battery bank which has 7 cells.

I found a great video from Andy Cartwright on YouTube whick allowed me to read 4 voltages using an ESP32 Dev Board and an Adafruit 1115 ADC module. Fig 1

Andy Cartwright video

I know you can use 2 Adafruit 1115 ADC modules by using different jumper connections on the ADDR pin but I do not know how to adjust the code to read from the 2nd ADC Fig2

Fig 1

Fig2

Serial output
Cell 1: 537.00
Cell 2: 546.00
Cell 3: 522.00
Cell 4: 522.00
Cell 5: 0.00
Cell 6: 0.00
Cell 7: 0.00

Code for 4 inputs

#include <Wire.h>
#include <Adafruit_ADS1X15.h>

Adafruit_ADS1115 ads; /* Use this for the 16-bit version */

void setup(void)
{
Serial.begin(115200);
Serial.println("Hello!");

Serial.println("Getting single-ended readings from AIN0..3");
Serial.println("ADC Range: +/- 6.144V (1 bit = 3mV/ADS1015, 0.1875mV/ADS1115)");

// The ADC input range (or gain) can be changed via the following
// functions, but be careful never to exceed VDD +0.3V max, or to
// exceed the upper and lower limits if you adjust the input range!
// Setting these values incorrectly may destroy your ADC

ads.setGain(GAIN_TWOTHIRDS); // 2/3x gain +/- 6.144V 1 bit = 0.1875mV (default)

ads.begin();
}

void loop (void)
{
int16_t adc0, adc1, adc2, adc3;

adc0 = ads.readADC_SingleEnded(0);
adc1 = ads.readADC_SingleEnded(1);
adc2 = ads.readADC_SingleEnded(2);
adc3 = ads.readADC_SingleEnded(3);

float fadc0, fadc1, fadc2, fadc3;

fadc0 = adc0 * 0.1875;
fadc1 = adc1 * 0.1875;
fadc2 = adc2 * 0.1875;
fadc3 = adc3 * 0.1875;

Serial.print("Cell 1: "); Serial.println(String(fadc0));
Serial.print("Cell 2: "); Serial.println(String(fadc1));
Serial.print("Cell 3: "); Serial.println(String(fadc2));
Serial.print("Cell 4: "); Serial.println(String(fadc3));
Serial.println(" ");

delay(1000);
}

Modified code for 7 inputs

#include <Wire.h>
#include <Adafruit_ADS1X15.h>

Adafruit_ADS1115 ads; /* Use this for the 16-bit version */

void setup(void)
{
Serial.begin(115200);
Serial.println("Hello!");

Serial.println("Getting single-ended readings from AIN0..3");
Serial.println("ADC Range: +/- 6.144V (1 bit = 3mV/ADS1015, 0.1875mV/ADS1115)");

// The ADC input range (or gain) can be changed via the following
// functions, but be careful never to exceed VDD +0.3V max, or to
// exceed the upper and lower limits if you adjust the input range!
// Setting these values incorrectly may destroy your ADC

ads.setGain(GAIN_TWOTHIRDS); // 2/3x gain +/- 6.144V 1 bit = 0.1875mV (default)

ads.begin();
}

void loop (void)
{
int16_t adc0, adc1, adc2, adc3, adc4, adc5, adc6;

adc0 = ads.readADC_SingleEnded(0);
adc1 = ads.readADC_SingleEnded(1);
adc2 = ads.readADC_SingleEnded(2);
adc3 = ads.readADC_SingleEnded(3);
adc4 = ads.readADC_SingleEnded(4);
adc5 = ads.readADC_SingleEnded(5);
adc6 = ads.readADC_SingleEnded(6);

float fadc0, fadc1, fadc2, fadc3, fadc4, fadc5, fadc6;

fadc0 = adc0 * 0.1875;
fadc1 = adc1 * 0.1875;
fadc2 = adc2 * 0.1875;
fadc3 = adc3 * 0.1875;
fadc4 = adc4 * 0.1875;
fadc5 = adc5 * 0.1875;
fadc6 = adc6 * 0.1875;

Serial.print("Cell 1: "); Serial.println(String(fadc0));
Serial.print("Cell 2: "); Serial.println(String(fadc1));
Serial.print("Cell 3: "); Serial.println(String(fadc2));
Serial.print("Cell 4: "); Serial.println(String(fadc3));
Serial.print("Cell 5: "); Serial.println(String(fadc4));
Serial.print("Cell 6: "); Serial.println(String(fadc5));
Serial.print("Cell 7: "); Serial.println(String(fadc6));
Serial.println(" ");

delay(1000);
}

[UKHeliBob]

@bobbych

Code for 4 inputs

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[wildbill]

You will need to declare two instances of an ADS1115 and use begin to specify that one of them is at a different I2C address. Adafruit's tutorial has the details and example code.

[bobbych]

@wildbill

Adafruit's tutorial

Thanks, I will try and find it

[jremington]

@bobbych

I want to read 7 voltages from an external battery bank which has 7 cells.

The voltages on the ADS1115 inputs MUST be between 0V and the ADS1115 supply voltage at all times.

[DrDiettrich]

@bobbych

I want to read 7 voltages from an external battery bank which has 7 cells.

You need differential reading, either per cell or in software by the voltage difference between 2 cells.

And you need voltage dividers to bring the full battery voltage down into the acceptable range, as @jremington pointed out already.

[bobbych]

@wildbill

ADS1115

Right. got it thanks

[bobbych]

Thanks

[DrDiettrich]

You can simply like whichever contribution was helpful.

[PaulRB]

int16_t adc0, adc1, adc2, adc3, adc4, adc5, adc6;

adc0 = ads.readADC_SingleEnded(0);
adc1 = ads.readADC_SingleEnded(1);
adc2 = ads.readADC_SingleEnded(2);
adc3 = ads.readADC_SingleEnded(3);
adc4 = ads.readADC_SingleEnded(4);
adc5 = ads.readADC_SingleEnded(5);
adc6 = ads.readADC_SingleEnded(6);

float fadc0, fadc1, fadc2, fadc3, fadc4, fadc5, fadc6;

fadc0 = adc0 * 0.1875;

You really, really need to learn to use arrays. Otherwise your entire sketch is going to be 7 times longer than it should be!

For example the above can be shortened to

int16_t adc[7];

for (byte c=0; c<7; c++) adc[c] = ads.readADC_SingleEnded(c);

float fadc[7];

for (byte c=0; c<7; c++) fadc[c] = adc[c] * 0.1875;

[TomGeorge]

Hi, @bobbych
Can you post a schematic showing how you will connect the ADCs to the batteries and to the ESP32.
Please include the batteries and all their connection.

PLEASE use a pen(cil) and paper to draw your diagram, labelling all components and pin names.

Thanks.. Tom...