I2C Scanner for Heltec ESP32 V2

#include <Wire.h>  //include Wire.h library
#define SCL_PIN 15
#define SDA_PIN 4
void setup() {
    Wire.begin(SDA_PIN, SCL_PIN);  // doesnt work
    //Wire.begin();  // works for SDA:21, SCL:22, but cant read Batterycharge
    Serial.begin(115200);
    while (!Serial)
        ;  // Waiting for Serial Monitor
    delay(750);
    Serial.println("\nI2C Scanner");
}

void loop() {
    byte error, address;  // variable for error and I2C address
    int nDevices;

    Serial.println("Scanning...");

    nDevices = 0;
    for (address = 2; address < 127; address++) {
        // The i2c_scanner uses the return value of
        // the Write.endTransmisstion to see if
        // a device did acknowledge to the address.
        Wire.beginTransmission(address);
        error = Wire.endTransmission();


        if (error == 0) {
            Serial.print("I2C device found at address 0x");
            if (address < 16) Serial.print("0");
            Serial.print(address, HEX);
            Serial.println("  !");
            nDevices++;
        } else if (error == 4) {
            Serial.print("Unknown error at address 0x");
            if (address < 16) Serial.print("0");
            Serial.println(address, HEX);
        }
    }
    if (nDevices == 0)
        Serial.println("No I2C devices found\n");
    else
        Serial.println("done\n");

    delay(5000);  // wait 5 seconds for the next I2C scan
}