Ok so I have 3 Temp sensors that display battery percentage pretty well and sleep for 5 minutes between reads.
Now through research on the forum I have put together a sketch for a door sensor that sleeps until interrupted and sends the battery percentage .
The problem I have is that the battery percentage varies with every read this is the serial monitor read:

3430 TSF:TDI:TSL
3432 MCO:SLP:WUP=-1
3436 TSF:TRI:TSB
3436 MCO:SLP:MS=0,SMS=0,I1=1,M1=1,I2=255,M2=255
3442 TSF:TDI:TSL
3444 MCO:SLP:WUP=1
3446 TSF:TRI:TSB
Sensor value: 832
Battery Voltage: 2.68 V
Battery percent: -2 %
3452 TSF:MSG:SEND,4-4-0-0,s=255,c=3,t=0,pt=1,l=1,sg=0,ft=0,st=OK:254
3463 TSF:MSG:SEND,4-4-0-0,s=3,c=1,t=16,pt=2,l=2,sg=0,ft=0,st=OK:1
Tripped3471 MCO:SLP:MS=5,SMS=0,I1=255,M1=255,I2=255,M2=255
3475 TSF:TDI:TSL
3477 MCO:SLP:WUP=-1
3479 TSF:TRI:TSB
3481 MCO:SLP:MS=0,SMS=0,I1=1,M1=1,I2=255,M2=255
3487 TSF:TDI:TSL
3489 MCO:SLP:WUP=1
3491 TSF:TRI:TSB
Sensor value: 953
Battery Voltage: 3.07 V
Battery percent: 62 %
3497 TSF:MSG:SEND,4-4-0-0,s=255,c=3,t=0,pt=1,l=1,sg=0,ft=0,st=OK:62
3508 TSF:MSG:SEND,4-4-0-0,s=3,c=1,t=16,pt=2,l=2,sg=0,ft=0,st=OK:0
Tripped3514 MCO:SLP:MS=5,SMS=0,I1=255,M1=255,I2=255,M2=255
3520 TSF:TDI:TSL
3522 MCO:SLP:WUP=-1
3524 TSF:TRI:TSB
3526 MCO:SLP:MS=0,SMS=0,I1=1,M1=1,I2=255,M2=255
3532 TSF:TDI:TSL
3534 MCO:SLP:WUP=1
3536 TSF:TRI:TSB
Sensor value: 930
Battery Voltage: 3.00 V
Battery percent: 50 %
3543 TSF:MSG:SEND,4-4-0-0,s=255,c=3,t=0,pt=1,l=1,sg=0,ft=0,st=OK:50
3553 TSF:MSG:SEND,4-4-0-0,s=3,c=1,t=16,pt=2,l=2,sg=0,ft=0,st=OK:1
Tripped3559 MCO:SLP:MS=5,SMS=0,I1=255,M1=255,I2=255,M2=255
3565 TSF:TDI:TSL
3567 MCO:SLP:WUP=-1
3569 TSF:TRI:TSB
3571 MCO:SLP:MS=0,SMS=0,I1=1,M1=1,I2=255,M2=255
3575 TSF:TDI:TSL
3577 MCO:SLP:WUP=1
3579 TSF:TRI:TSB
Sensor value: 854
Battery Voltage: 2.75 V
Battery percent: 9 %
3586 TSF:MSG:SEND,4-4-0-0,s=255,c=3,t=0,pt=1,l=1,sg=0,ft=0,st=OK:9
3596 TSF:MSG:SEND,4-4-0-0,s=3,c=1,t=16,pt=2,l=2,sg=0,ft=0,st=OK:0
Tripped3604 MCO:SLP:MS=5,SMS=0,I1=255,M1=255,I2=255,M2=255```

and this is the sketch;

/**
 * The MySensors Arduino library handles the wireless radio link and protocol
 * between your home built sensors/actuators and HA controller of choice.
 * The sensors forms a self healing radio network with optional repeaters. Each
 * repeater and gateway builds a routing tables in EEPROM which keeps track of the
 * network topology allowing messages to be routed to nodes.
 *
 * Created by Henrik Ekblad <henrik.ekblad@mysensors.org>
 * Copyright (C) 2013-2015 Sensnology AB
 * Full contributor list: https://github.com/mysensors/Arduino/graphs/contributors
 *
 * Documentation: http://www.mysensors.org
 * Support Forum: http://forum.mysensors.org
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 *******************************
 *
 * DESCRIPTION
 *
 * Simple binary switch example 
 * Connect button or door/window reed switch between 
 * digitial I/O pin 3 (BUTTON_PIN below) and GND.
 * http://www.mysensors.org/build/binary
 */


// Enable debug prints to serial monitor
#define MY_DEBUG 

// Enable and select radio type attached
#define MY_RADIO_NRF24
//#define MY_RADIO_RFM69

#define MY_NODE_ID 4

#include <SPI.h>
#include <MySensors.h>


#define CHILD_ID 3
#define BUTTON_PIN  3  // Arduino Digital I/O pin for button/reed switch

#define SLEEP_TIME 0 // sleep forever

// Change to V_LIGHT if you use S_LIGHT in presentation below
MyMessage msg(CHILD_ID,V_TRIPPED);

// ------------------ BATTERY ------------------
int BATTERY_SENSE_PIN = A0;  // select the input pin for the battery sense point
int oldBatteryPcnt = 0;  // remember last measured percentage
#define V_MIN 2.7  // 0% Battery voltage
#define V_MAX 3.3  // 100% Battery voltage

byte oldSwitch_State = HIGH; 


void setup()  
{  
  // Setup the button
  pinMode(BUTTON_PIN,INPUT);
  // Activate internal pull-up
  digitalWrite(BUTTON_PIN,HIGH);
  
  
  // Setup 1.1 V internal reference for analoge GPIO
  analogReference(INTERNAL);
  
}

void presentation() {
  // Register binary input sensor to gw (they will be created as child devices)
  // You can use S_DOOR, S_MOTION or S_LIGHT here depending on your usage. 
  // If S_LIGHT is used, remember to update variable type you send in. See "msg" above.
  present(CHILD_ID, S_DOOR);  
}


//  Check if digital input has changed and send in new value
void loop() 
{
  // read analog pin
  int sensorValue = analogRead(BATTERY_SENSE_PIN);
  // calculate battery voltage
  float vBat  = static_cast<float>(sensorValue * (V_MAX/1023));
  // calculate % left of defined interval
  int batteryPcnt = static_cast<int>(((vBat-V_MIN)/(V_MAX-V_MIN))*100.);  
  // debugging
  #ifdef MY_DEBUG
    Serial.print("Sensor value: ");
    Serial.println(sensorValue);
    Serial.print("Battery Voltage: ");
    Serial.print(vBat);
    Serial.println(" V");
    Serial.print("Battery percent: ");
    Serial.print(batteryPcnt);
    Serial.println(" %");
  #endif
  // If battery % has change send to controller
  if (oldBatteryPcnt != batteryPcnt) {
    // Power up radio after sleep
    sendBatteryLevel(batteryPcnt);
    oldBatteryPcnt = batteryPcnt;
    
  }
{
 
 {
  
   byte switchState = digitalRead (BUTTON_PIN);
  
    
  
  if (switchState != oldSwitch_State) {
     // Send in the new value
     send(msg.set(switchState==LOW ? 1 : 0));
     oldSwitch_State = switchState;

     sleep(5);
  }
   

 sleep(digitalPinToInterrupt(BUTTON_PIN), CHANGE, SLEEP_TIME);
} 
}
}

I have the resistors set up as described here
with the addition of a 0.1uF cap over R2 (470KΩ) resistor

is there a way to stabilize these readings ?

GreyLinux