ESP32 Forum

Hey Guys,
I am totally new to powering microcontrollers, that's why I am not sure about how to power my project correctly.
I wan to build a mobile setup using the esp32 WROOM-Breakout from board from sparkfun. Ideally, the power should last for a few days for my project. Basically, the projects consists of regularly accelerometer-data via bluetooth. In between the measurements the esp32 will stay in sleep mode to save power.
The size of the batteries is also critical, so I would prefer a smaller sized battery like a coin cell or a small LiPo-battery.
One possible power supply could be a LiPo battery 3.7V, 200mah. But during development, I am powering the project using the micro-usb port which provides 5V. So I am basically not sure if a 3.7V battery can afford the same power. As I know, the IO-pins are powered with 3.3V Does the breadboard down-regulate the 5V and will 3.7V be enough to power the esp32?
I have to apologize for such beginner-questions but I couldn't find a similar project reference to validate my assumptions.

Kind regards,
RSchlenker

5V power supply would damage esp.
Esp if you're not too frugal (wifi on, low value resistors for pullups) needs about 0.2A and your battery will die in 1 hour.

Hello,
it should be possible to power the ESP from a LIPO. They have often discharge rates of about 20 C/H (C = capacity in AH). But you need a voltage regulator with a very low drop.
I'm using the TPS73733. Maybe you can think about a switching regulator, but I don't know if this is the best choice for a Ultra Low Power application. The TPS73733 has a maximum Input of 5.5V so USB is no problem.

Kind regards
Peter

PS. (Just see that the TPS consums about 400µA so maybe you must look a little bit around for some regulator with a lower consumption.)

Maybe disable the TPS during sleep, and bypass it with a couple of Si diodes to drop the voltage into the safe range?


Cheers
Hans

Maybe a joule thief
You can use your 0.2Ah battery. Value 0.2A (and even more) I wrote before is true when everything is on. Just remember about it writing a code, switch into powersave mode as often as it is possible, use pullups 10k and do not use a wifi too often

Hi RSchlenker,

Since you mention using a SparkFun board, as far as I know their only ESP32 product is the ESP32 Thing (https://www.sparkfun.com/products/13907). If you're using this board, it embeds everything you need for power management. Just connect a LiPo battery to the JST connector and the battery voltage will be correctly regulated for the ESP32. You can also plug a Micro USB cable to power the board and/or charge the battery, and again the 5V from USB will be regulated to 3.3V.

Cheers,

Philippe

Hello,

Does anybody know what the maximum input voltage is an ESP32 board could handle?
I would like too built the board into a machine what has already a power supply of around 9 volts.
I am looking for an board which can coop with this voltage and has bluetooth.
adruino uno's are able up to 12 volt but do'nt have Bluetooth or WIFI built on.