ESP32 Battery Life Tips

Just some things I've learned about increasing battery life when using ESP32 boards. Also, some follow ups on the battery life achieved on a few past projects.
=== Timestamps ===
00:00 Introduction
00:22 Update: Voice Remote
03:19 Update: Soil Moisture Sensor
05:35 Tips
06:22 1 - Use an On/Off switch
07:10 2 - Min Wake, Max Sleep
09:33 3 - Use a low power board
11:09 4 - Turn off peripherals
11:41 5 - Use higher value resistors
12:44 6 - Use GPIO pins for power
14:42 7 - Don't overuse LEDs
15:11 8 - Just use a bigger battery
16:36 Conclusion

[@codybarker9942]

This was just what I needed! I'm building out some weather proof moisture sensors for our nursery and have had trouble with poor battery life in the past. Thank you!

[@roshanyadav890]

Thanks for the tips! Great video. Will try to design something using the ESP32-C3 soon.

[@rootdev8106]

Thank you, this is very useful!!

[@chamodhdissanayake9831]

Informative video...is there any way to apply an energy harvesting application to this so that the battery itself can be charged without disassembling the whole thing?

[@TechDregs]

Some ESP32 boards come with built in battery management chips, and for those you can incorporate charging solutions. See:
th-cam.com/video/Yttauf94A04/w-d-xo.html
th-cam.com/video/EeUG3Si9fZk/w-d-xo.html
th-cam.com/video/TFiI0tqjUzw/w-d-xo.html

[@benjaminhobbs2923]

I've heard people saying I need to use a 'buck converter' when adding a LiFePO4 battery, as their voltage when fully charged is around 4.2V, and the ESP32 only allows up to 3.6V (max). Have you used a converter too? And if so do you have any advice on where to start? Thanks:)

[@TechDregs]

Unfortunately, I don't have any experience with that battery chemistry.

[@mtraven23]

firstly, the way you wrote that makes it sound like you were thinking you could just plug your battery directly into your board, there is no circumstance that allows for that(unless, maybe you have some special module with extra hardware). 4v is too low for the internal regulator to do its job.
you have 2 options to solve that...buck the voltage up to ~5-7V and run that into Vin, for the regulator to drop it to the right voltage.
OR
you can use the 3.5-4v you get straight off the battery, run it through an LDO (low drop out regulator) and then directly into Vcc, bypassing the internal regulator.
In my current project, I opted for the later as I suspect it to be more efficient. Its worked out well for me. The buck convertor would probably be a module you just add, the LDO approach probably requires a bit of soldering on a protoboard (it did for me).
good luck with your project!

[@tbandras]

Hey there! I came across this video after watching your take on the soil moisture sensor. I have tried to read up on the GPIO usage for powering the sensor, but I seem to have reached a dead end. Using a C3 Xiao I can't seem to utilize the GPIO for power for my moisture sensor that has the TL555 chip. I am getting consistent and good readings from the 3v3 output pin, but not from the GPIO. Do you have any advice? (I have the switch configured for GPIO21 and it turns on on boot)

[@TechDregs]

What does your code look like for it? Perhaps there's an error somewhere.

[@tbandras]

@@TechDregs I am trying to post the (hopefully) relevant sections:
esphome:
name: wifi-moisture-sensor
friendly_name: Lawn Moisture Sensor
on_boot:
then:
- switch.turn_on: sensor_power
on_shutdown:
then:
- switch.turn_off: sensor_power
esp32:
board: esp32-c3-devkitm-1
framework:
type: arduino
switch:
- platform: gpio
pin: GPIO21
id: sensor_power
internal: true

[@TechDregs]

So you're not getting any voltage out of GPIO21 when you check with a multimeter? If you've already checked your wiring, I might try a different pin. I don't see any issues in what you posted.

[@ericbommer2280]

I have been working on a battery project for a while and having issues with brownout. I am powering my project using 2 AAA batteries and a step-up 3.3v switch supply, with a Lolin s2 mini. From my research my current fix is a 1000 uF capacitor on the power line. I went with the Lolin S2 mini because it doesn't need use a USB to UART converter and is a bug battery save. Anyway I see you don't seem to be using any bulk capacitance on any of your projects. Curious if you have experience this problem in the past on how did you get around it. Thanks. As a side note on your switch comment, I am also investigating using a magnetic reed switch as a power switch, that way i can contain my project better from the environment. So far seems to be working,

[@TechDregs]

No, never had to use any caps, but I've always used LiPo batteries rather than normal batteries, and I don't think anything I've done has required much power. Possibly the battery discharge capabilities could have some impact on requiring caps.