ESP32 Forum

I have Esp32Devkitc v4 which I am trying to run using external battery that is connected through a regulator to the Dev kit pin 3.3V and Ground.
Esp32DevKitc v4 works ok with the usb power and wakes up from deepsleep mode when button on Pin 27 is presses (EXT0 source)

but when I power board with battery that is using Li-SOCI2 LS14500 series 3.7V battery via microchip's regulator MIC5209-3.3YS-TR
it does not wakeup from deep sleep mode . Although, it works ok when I do not put device in sleep mode (that is normal or active mode) even connected witht the batter.

I am using PIN27 of ESP32 WROOM-32D and programming the device using Arduino IDE.

Hi,

Do you still have this issue? Any updates on that?

Hi I still have the issue.

Hi,

I think it is something related to your battery voltage drop + the LDO dropout. Have you tried to connect the battery without the LDO or to use an external 3V6 power supply? You can do this because the ESP32 works with VCC up to 3V6.

Do not power the ESP32 directly with more than 3V6 or using batteries that holds more than 3V6 when fully charged.


Can you also check if there is any log output from the serial?

Also check this out: viewtopic.php?t=5018

Hi Esp_minatel,

Thanks for your response. Link you have shared is very helpful to understand different ways of powering up the ESP32 thanks very much for that and much appreciated.
I am back on it now.
I have checked the datasheet of ESP32 WROOM 32D and the maximum voltage it can withstand is 3.6V while, my batteries have 3.78V ( it says 3.6V but most of the new batteries are usually above their mentioned voltage) that can burn the ESP32 because the voltage applied on the 3.3V pin goes unregulated unless we externally use a regulator as I was using.

I think I have found the issue.

According to the SAFT LS14500 AA batter datasheet

Nominal voltage (at 0.2 mA + 20°C) 3.6 V

which means current supplied nominal is 0.2mA

and

Pulse capability: Typically up to 250 mA

While esp32 datasheet says

minimum active state current required is 0.5A or 500mA which will be required to wake up the device . That means device will need a spike of current from sleep mode to wake up (active mode) transition which this battery is not capable of.
I will now try a different battery with higher current (upto 500mA at least ) output capabilities.
Thanks for your help @ESP_Minatel.

Hi,

It makes sense.

One thing that you can try is to add some capacitor (capacitance > 1000uF) in parallel with the battery for testing.