user48252: I am using a NodeMCU v.1.0 ESP-12 for a small project. It is powered by 3xAA batteries (4.5v) in Vin, but to reduce power consumption I need to put in in deepsleep every now and then.
Running this small sketch:
void setup() {
  Serial.begin(115200);
  Serial.setTimeout(2000);

  // Wait for serial to initialize.
  while(!Serial) { }

  Serial.println("I'm awake.");

  Serial.println("Going into deep sleep for 20 seconds");
  ESP.deepSleep(20e6); // 20e6 is 20 seconds
}

void loop() {
}

I have measured a consumption of 8mA when it goes to deepsleep, and this is not acceptable for my purpose. In order to wake up from sleep I have connected pin GPIO16 (D0) to RST, and it works. I knew that NodeMCU should have only few µA of consumption in deepsleep. How can I fix this?

user38697: Consider the TI TPL5110 timer chip with power control MOSFET. Set the timer period with a resistor then the TPL5110 powers on the NodeMCU periodically. Deep sleep is not used. RTC RAM will be lost so use SPIFFS for persistent data.
Adafruit has a breakout board. Take a look in Adafruit's forum for user comments because it has a few limitations.

48252: <p>I am using a NodeMCU v.1.0 ESP-12 for a small project. It is powered by 3xAA batteries (4.5v) in Vin, but to reduce power consumption I need to put in in deepsleep every now and then.</p>

<p>Running this small sketch:</p>

<pre><code>void setup() {
  Serial.begin(115200);
  Serial.setTimeout(2000);

  // Wait for serial to initialize.
  while(!Serial) { }

  Serial.println("I'm awake.");

  Serial.println("Going into deep sleep for 20 seconds");
  ESP.deepSleep(20e6); // 20e6 is 20 seconds
}

void loop() {
}
</code></pre>

<p>I have measured a consumption of 8mA when it goes to deepsleep, and this is not acceptable for my purpose. In order to wake up from sleep I have connected pin GPIO16 (D0) to RST, and it works. I knew that NodeMCU should have only few µA of consumption in deepsleep. How can I fix this?</p>
 38697: <p>Consider the TI TPL5110 timer chip with power control MOSFET. Set the timer period with a resistor then the TPL5110 powers on the NodeMCU periodically. Deep sleep is not used. RTC RAM will be lost so use SPIFFS for persistent data.</p>

<p>Adafruit has a breakout board. Take a look in Adafruit's forum for user comments because it has a few limitations.</p>
