Microcontroller
In this post, I’d like to take a moment to introduce the various ESP microcontrollers with Wi-Fi that I’ve used over time, in terms of battery operation.
All devices are Wi-Fi capable and you can use ESP-NOW for communication, for example.
| Microcontroller | Normal operation Wifi ON | Normal operation Wifi Off | Deep Sleep | Day in Deep Sleep with a 1000 mAh battery* |
| WEMOS D1 mini v3.0 Unfortunately no battery connector  Connection Micro-USB: Connection at 5V Pin has the same values | 67 mA | 15 mA | 44 uA | 976 Days |
| WEMOS D1 mini v3.0 with WEMOS Battery Shield  Connection battery port at the battery shield | 140 mA | 24 mA | 910 uA | 45 Days |
| Connection at Micro-USB from Battery Shield: | 70 mA | 18 mA | 3,54 mA | 12 Days |
| Connection Micro-USB from D1 mini: | 67 mA | 15 mA | 560 uA | 74 Days |
LOLIN32 Connection at battery port: | 114 mA | 39 mA | 350 uA | 119 Days |
| Connection Micro-USB: | 115 mA | 39 mA | 914uA | 44 Days |
Firebeetle32 V4.0 Connection battery port: | 115 mA | 38 mA | 13 uA | 3205 Days |
| Connection Micro-USB: | 116 mA | 39 mA | 670 uA | 62 Days |
| Connection VCC – with 5V: | 115 mA | 39 mA | 11 uA | 3787 Days |
| ESP32 – Devkit DOIT V1 Unfortunately no battery connector  Connection Micro-USB: | 131 mA | 55 mA | 17 mA | 2,4 Days |
* The value is only intended to provide a quick overview and is purely arithmetical. The duration is also affected by other factors, such as: self-discharge of the battery, discharge curve of the battery, the “awake” times of the microcontroller, etc.. These are not taken into account here.
CONCLUSION
Based on the table, I think you can pick the right microcontroller for your application.
The Firebeetle32 board from DFRobot is quite unrivaled when it comes to long battery use.
I was particularly disappointed here with the Battery Shield from WEMOS. Since the D1 Mini had such good values, I had hoped to have an inexpensive battery combination along with the Battery Shield. But that this itself has such a high power consumption is disappointing.
Battery Shields
Here are the results of my tests with some battery shields I tested.
| Shield | Self-consumption | Days with a 1000 mAh battery without consumer |
| 18650 Battery Shield V3 for 1 x 18650 battery  | Consistently 350 uA consumption, whether it is ON or OFF. | 119 Days |
| 18650 Battery Shield V9 for 4 x 18650 batteries  Is not usable for a “deep sleep” project. Switches off at low current consumption and you have to press the on button again. | Standby(OFF): 200 uA ON: 107 mA | Standby: 208 Days ON: 0,4 Days |