ESP8266 Community Forum

Posted: **Thu Jun 18, 2015 11:50 am**

Hi,
I am using deep sleep mode in monitoring a DHT22 for H2O and temperature and therefore reducing the drain on a LiFe PO4 battery between readings (ESP8266-12) I also monitor the battery voltage through the ADC (TOUT) port (I have a 1/4 voltage divider in order not to exceed 1 V on the analog input) When the battery voltage gets below 2.8 V I want to put the ESP into a very long deep sleep in order not to run the battery to a too low voltage. Any idea about the maximum time the ESP can be put into deep sleep? I am using 15 min between readings with no problem;
e.g. : system_deep_sleep(900000000);

Thanks

Posted: **Thu Jun 18, 2015 12:07 pm**

Hi

According to the Espressif IoT SDK Programming Guide its defined as

void system_deep_sleep(uint32 time_in_us) so that would be 4294967295uS = 1.19hours if my calculation is correct.

Gerry

Posted: **Thu Jun 18, 2015 2:19 pm**

Thank you Gerry.
S.

Posted: **Sat Sep 22, 2018 5:29 am**

GerryKeely wrote:Hi

void system_deep_sleep(uint32 time_in_us) so that would be 4294967295uS = 1.19hours if my calculation is correct.

Gerry

Where did that number come from?

ESP8266 Community Forum

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