ESP32 with Alkaline Batteries

kian79
Posts: 17
Joined: Thu Jun 13, 2019 3:27 am

ESP32 with Alkaline Batteries

Postby kian79 » Thu Jun 20, 2019 12:53 pm

Hi all,

Anyone here has developed or worked on applications for the ESP32 using standard alkaline batteries? I was originally intending to use a CR2032 lithium battery for an ESP32 project, but read on the forum that this is not possible given that the ESP32 requires a large current for Wifi. Hence I am thinking of switching over to using standard Alkaline (AA or AAA) batteries.

My application only requires the ESP32 to wake up around 5 times a day, connect to Wifi, read a sensor, publish to a MQTT broker, disconnect and go to deep sleep until the next event occurs.

What would be the best combination in this case? Using 2 AA or AAA batteries to give 3V and use a boost converter to get 3.3V or using 3 AA or AAA batteries to give 4.5V and using a LDO to drop the voltage down to 3.3V? Or are there other recommendations? I want to avoid using rechargeable lithium batteries in my application.

Thanks!

mitchk
Posts: 11
Joined: Fri Apr 28, 2017 8:31 pm

Re: ESP32 with Alkaline Batteries

Postby mitchk » Thu Jun 20, 2019 1:42 pm

I am working on a project where I plan to use 2 AA size Alkaline or Ni-MH batteries. I am using the TI TPS613221A to boost the voltage up to 3.3V. Per the datasheet I am using the part with an external schottky diode for higher output current operation. I just got in my hardware and haven't done much testing yet but it can provide enough current to run the Wi-Fi station example from the ESP-IDF with no issues and when I ran the deep sleep example I measured a total board current draw of 300uA. That is with an ESP-WROOM-32D module on board.

mikemoy
Posts: 402
Joined: Fri Jan 12, 2018 9:10 pm

Re: ESP32 with Alkaline Batteries

Postby mikemoy » Thu Jun 20, 2019 2:54 pm

3 AA and a LDO would be better. Boosting up the voltage from 2 will require more current than dropping down.
Honestly using a switching regulator would be even better as they are more efficient than a LDO.
I have used this for a couple years now and they are great ~90% efficient.
https://www.digikey.com/product-detail/ ... ND/4499516

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