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by nunobrito 250 days ago
Compared to other microcontrollers: ESP32 is very power hungry. Shiny displays are very power hungry, Wi-Fi is power hungry. So expect to draw about 5 watts/hour continuously while in operation with all bells and whistles.

With this said (I'm also using them for off-grid) you will need to put them to sleep and only use the display when absolutely needed for most scenarios. I've recently started using devices with e-paper display which at least solve that nuisance of the display power draw: https://www.waveshare.com/wiki/ESP32-S3-ePaper-1.54

The last thing to keep in mind is heating. They will warm quite a bit and you should consider a way to either keep them cooled or make them sleep enough to cooldown, otherwise they will reboot or stop working until they are cooled again.

2 comments

Depends... do you need wifi, screen and others always on? can you wake some on a timer? on user interaction? on interrupts?

https://lastminuteengineers.com/esp32-sleep-modes-power-cons...

You can use those sleep modes in micropython as well

https://randomnerdtutorials.com/micropython-esp32-deep-sleep...

> 5 watts/hour

Typo I'm guessing, but I found this unit of "energy acceleration" amusing.

"Gotta go fast" :-)

In my language we say it colloquially that way, turned out wrong in English. Should have been 5 Wh.

Rather you would say it draws 5 watts. If someone is interested in draw over a period, e.g. over one hour, you'd say it used 5Wh in that period.
> If someone is interested in draw over a period, e.g. over one hour, you'd say it used 5Wh in that period.

Wh per hr? Let's just cut through the confusion and say it draws (J/s)Hr / Hr. :P

More seriously, if you are interested in energy the "correct" SI unit is J although in electrical applications [k/Mega/Giga]Whr is common. If you are interested in energy draw over a period, aka power, the "correct" and common unit is W. While 5 Wh per hour might seem simpler, it is equivalent to say this thing draws as much energy per hour as a device that that draws 5W would draw over one hour - needlessly redundant.

In the offgrid world we look constantly at batteries and they often express themselves in Wh. So it is a habit to measure anything else that way to avoid confusions.