Can I power a GPS from the ESP32 3.3v pin?

I'm having trouble trying to see what the max amp draw can be from the 3.3v pin on the esp32. I was hoping I could power this GPS that is rated 28ma on that pin, saving me from using another regulator: SparkFun GPS Breakout - Chip Antenna, SAM-M8Q (Qwiic) - GPS-15210 - SparkFun Electronics

I'm powering my ESP32 using the vcc pin at 7v.

Please supply a link to the ESP32 you have.

it depends on the on board regulator but you should be fine with 28mA

Any reason you chose 7V for powering the board?

Thanks I believe it's this one ESP32-DevKitC

Any reason you chose 7V for powering the board?

I'm using 2 x 18650 cells in series.

do you have anything needing 7V ?

If the regulator used on the board is an AMS1117, which is often used, then its got a droput in the 1V range.

Just the ESP32 that requires 5v - 12v on the vcc pin.

(It depends on the board, an esp by itself is fine with less)

Indeed but a single cell will run down too low (2.5v) for the board.

The ESP32-DevKitC will need to be powered either through USB or the Vcc pins I guess and go through the regulator. The more voltage you send in, the more the voltage regulator will have to drop to provide the 3.3V required by the board. So it's not very energy efficient.

The 3.3V pin gets it's current from that regulator, so powering your GPS if it only draws 28mA should be fine, there should be plenty of mA left to run the board from your 2 x 18650 cells in series if they are delivering more than 600mAh

An ESP32 runs fine between 2,55 to 3,6 volts if you don't want your ESP to die unexpectedly and require a proper shutdown process you'd need extra equipment

I've used two 1.5 V lithium batteries in series or one 3 V CR123 lithium battery (Varta CR123 - 3 V, 1700 mAh) for some projects where the ESP was sleeping most of the time

Thanks! Good to know!

but your module requires more power probably as it has lots of hungry components :slight_smile: