I'm attempting to read the battery voltage on my Heltec WiFi LoRa 32 V3. The voltage is consistently displayed as "0.00V" on the E-Ink screen.

[parahooners]

Battery Voltage Reading 0.00V on Heltec WiFi LoRa 32 V3 with E-Ink

Long and short iv used the example and the it shows 0.00 and no reading ?

Battery Voltage Reading 0.00V on Heltec WiFi LoRa 32 V3 with E-Ink

Board: Heltec WiFi LoRa 32 V3
Pin Used for Battery Voltage: GPIO7 (ADC1_CHANNEL_6)
Display: Heltec E-Ink Display (likely 2.13-inch based on project context)

Problem Description:
I'm attempting to read the battery voltage on my Heltec WiFi LoRa 32 V3. The voltage is consistently displayed as "0.00V" on the E-Ink screen.

Relevant Code:

1. Pin Setup in setup():

   pinMode(7, INPUT);
   // analogReadResolution(12); // This was present in factory test, tried with and without

2. getBatteryVoltage() function:

   // Constants derived from factory test code
   const float RESOLUTION_FACTOR = 0.000244140625; // 1/4096 for 12-bit ADC
   const float ADC_REF_VOLTAGE = 3.3;             // ESP32 ADC reference voltage
   const float DIVIDER_COEFFICIENT = 4.01;        // Voltage divider factor
   
   float getBatteryVoltage() {
     int rawValue = analogRead(7);
     // Serial.print("Raw ADC (GPIO7): "); // For debugging
     // Serial.println(rawValue);
     float voltage = rawValue * RESOLUTION_FACTOR * ADC_REF_VOLTAGE * DIVIDER_COEFFICIENT;
     return voltage;
   }

3. Display Code Snippet (in drawBackground()):

   display.setFont(&tahoma7pt7b); // Smaller font for battery
   float battVoltage = getBatteryVoltage();
   char battBuffer[15];
   snprintf(battBuffer, sizeof(battBuffer), "Batt: %.2fV", battVoltage);
   // ... (code to display battBuffer) ...

Context & Troubleshooting Steps Taken:

• The pin (GPIO7) and calculation constants (RESOLUTION_FACTOR, ADC_REF_VOLTAGE, DIVIDER_COEFFICIENT) are based on the official Heltec factory test code for this board, which successfully reads the battery voltage.
• The factory test code also included analogReadResolution(12);. I have tried including this in my setup() function, but it did not change the 0.00V reading.
• The rest of the E-Ink display functionalities, GPS, and LoRa (though LoRa is not actively used in this specific test) seem to be working as expected.
• I've tried adding Serial.print for the raw ADC value, but I'm currently viewing output on the E-Ink. If serial debugging is crucial, I can set that up.

Factory Test Code Reference (Conceptual):
The factory test code had a function similar to this:

// #define Resolution 0.000244140625
// #define battary_in 3.3
// #define coefficient 4.01
// float battery_levl;

// void battery() {
//   analogReadResolution(12);
//   battery_levl = analogRead(7) * Resolution * battary_in * coefficient;
// }

// It also had a VextON() function:
// void VextON(void)
// {
//   pinMode(18,OUTPUT);
//   pinMode(46,OUTPUT);
//   digitalWrite(18, HIGH);
//   digitalWrite(46, HIGH);
// }
// And VextON() was called in its setup().