ESP8266 Deep Sleep Energy Saving

After reading many post of people getting months of ESP8266 running time off batteries I decided to set up my own to see why my battery life was terrible:

Node MCU ESP8266 (CH349G Serial Chip, AMS1117 Voltage Regulator)
LiPo Battery: 2S 850mAh (7.4V)
ADS1115 ADC (to measure voltage, 500K Voltage divider)

Test setup:
Two ESP8266 setups were completed, one ESP was standard and the other had the LED and Serial Chip disconnected to conserve Battery.

Test Program:
ESP Wake every 20 seconds (with radio disabled)
Take voltage reading and store in RTC memory
Deep Sleep
Every 5 minutes (15 wake cycles)
Take voltage reading
Connect to network and transmit all data to Influx Database.
Disconnect from network
Deep Sleep

You can see from the below screenshot the battery voltage over the duration of the test:

Unmodified ESP8266:
Time from 8.36V to 7.28V (97% to 7% of Li-Po capacity) was 87hrs and 20mins (3.6 Days)

Modified ESP8266: (No LED or Serial Chip)
Time from 8.36V to 7.28V (97% to 7% of Li-Po capacity) was 101hrs and 16mins (4.2 Days)

Months of usage seem far from achievable with a minimal setup and all precautions taken. Actually the ESP seems pretty unusable on a battery for anything more than a measurement every few hours.

Further Improvements:
The stock voltage regulator is a known power drain, an alternative is recommended but I did not get around to that yet.

That’s it!

ESP8266 logging to InfluxDB

The ESP8266 is a $5 IOT device with huge capabilities. In this post we will log data to a remote Influx database running on a RaspberryPi.

I am programming the ESP8266 in the Arduino IDE, the ESP8266 library is required, you can find it here. I have a test code file (of copy from below) that you can upload after entering your InfluxDB I.P. Address, SSID & Password and it will start logging data immediately.

#include <ESP8266WiFi.h>
#include <ESP8266WiFiMulti.h>
#include <InfluxDb.h>

#define INFLUXDB_HOST ""   //Enter IP of device running Influx Database
#define WIFI_SSID "SSID"              //Enter SSID of your WIFI Access Point
#define WIFI_PASS "PASSWORD"          //Enter Password of your WIFI Access Point

ESP8266WiFiMulti WiFiMulti;
Influxdb influx(INFLUXDB_HOST);

void setup() {
  Serial.print("Connecting to WIFI");
  while ( != WL_CONNECTED) {
  Serial.println("WiFi connected");
  Serial.println("IP address: ");


  Serial.println("Setup Complete.");

int loopCount = 0;

void loop() {

  InfluxData row("data");
  row.addTag("Device", "ESP8266");
  row.addTag("Sensor", "Temp");
  row.addTag("Unit", "Celsius");
  row.addValue("LoopCount", loopCount);
  row.addValue("RandomValue", random(10, 40));


The Arduino Serial Terminal will display something like the below so you can if it is working. (My previous tutorial shows setting up InfluxDB, ensure you have the database “esp8266_test” created as we are going to write to that.)

 --> writing to esp8266_test:
data,Device=ESP8266,Sensor=Temp,Unit=Celsius LoopCount=256.00,RandomValue=37.00
 <-- Response: 204 ""
 --> writing to esp8266_test:
data,Device=ESP8266,Sensor=Temp,Unit=Celsius LoopCount=257.00,RandomValue=20.00
 <-- Response: 204

On the Influx Database we can look at the data by:

USE esp8266_test
select * from data limit 50

Below you can see the export from my database (I have shortened the time field for neatness). You can see I reset the ESP8266 a couple of times due to the LoopCount value.

time        Device  LoopCount RandomValue Sensor Unit    
----        ------  --------- ----------- ------ ----   
52808175073 ESP8266 1         38          Temp   Celsius                              
63108846141 ESP8266 2         35          Temp   Celsius                              
69802517277 ESP8266 1         13          Temp   Celsius                              
79892112240 ESP8266 2         12          Temp   Celsius                              
89961602267 ESP8266 3         14          Temp   Celsius                              
99998928411 ESP8266 4         22          Temp   Celsius                              
10053683452 ESP8266 5         10          Temp   Celsius                              
20120378415 ESP8266 6         28          Temp   Celsius                              
30175745403 ESP8266 7         14          Temp   Celsius                              
40732248123 ESP8266 8         38          Temp   Celsius                              
51232948067 ESP8266 9         15          Temp   Celsius                              
61322347831 ESP8266 10        13          Temp   Celsius                              
71424432515 ESP8266 11        19          Temp   Celsius                              
84740185749 ESP8266 1         18          Temp   Celsius                              
94790343615 ESP8266 2         21          Temp   Celsius                              
04839215465 ESP8266 3         13          Temp   Celsius                              
31864448941 ESP8266 1         32          Temp   Celsius                              
41956355523 ESP8266 2         36          Temp   Celsius                              
52018136222 ESP8266 3         30          Temp   Celsius                              
62083037888 ESP8266 4         22          Temp   Celsius       

That’s it!