High Power Consumption ESP32 PoE

[stoneweg]

Hi together!

I just installed my first ESP32 PoE to measure temperature (BME280) and motion (just a normal PIR), and I was a bit surprised about the high power consumption: my switch tells me it is 1.3 W.

Can I do anything to reduce the power consumption? I read about turning of radio, but I also read that will only reduce by about 50 mA (0.25 W). I was hoping to be below 0.5 W for my setup.

Any ideas?

Thanks!

[LubOlimex]

Seems normal. Around 1W is the expected consumption when powered from PoE and in regular mode. You should experiment with light-sleep and deep-sleep modes. However, notice that the ESP32 boards were designed for minimum power consumption only when powered by Li-Po battery, you might not reach as low power consumption when you power it from the PoE.

[stoneweg]

Thanks for the answer!

[mihaiadrian]

You are very good at 1.3w.

I am at 2.4w with  MOD-LC2.8RTP , BME280 and ESP32 running dual core at 240 Mhz. MOD-LC2.8RTP consumes around 0.7w.
I managed to reduce ESP32 frecvency to 10 Mhz and have ESP32 cable network + MOD-LC2.8RTP  + BME280 working, but unfortunately I don;t have yet information how much the power got (hopefully) reduced

Regards,
 

[mihaiadrian]

After freq reduction to 10Mhz, but with some spikes ( less than 100ms at every 10s )  where I increase freq to 40Mhz in order to speed up LCD update , I get around 2-2.2w power consumption with above setup

Further I will try to remove R41  .    I hope to get 1w power save but will see ....

I think the best scenarios is without R41 and with sleep modes but this maybe impossible - the switch might cut the power . But maybe I am able to compensate the "consumption need" with LCD instead of R41.  Also unsure if sleep is compatible with wired network ....Will see

[mihaiadrian]

I removed R41 ( i think is 4kOhm - so, this means around 0.62w theoretic) .  The power saving is a lot from swtich web interface. Before I had 2.2 - 2.4w power consumption ( this includes Olimex 2.8 UEXT LCD and Olimex BME280 sensor ).  Now I have just 1.5w .   To summarize, removing r41 results in a 0.7 - 0.9w efficiency..  Not to mention board temp is less now ( but still a little warm ).


After doing the modifications described here:  https://www.olimex.com/forum/index.php?topic=8922.0  ,  ESP32-POE-ISO with 2.8 LCD with backlight off and with Olimex BME280, I get 1.2 power consumption.  If I completely remove display, than I have 1.1 w power consumption.

Note: all the test were made with board running at 10 Mhz , with cable network being used sometimes and with 2 threads running in my app ( but not fully stressing cpu - just some usage which I find it hard to describe in words )

No test yet to check if switch shuts down the power when put in deep sleep without r41....... But even if it does, I do hope the 0.1w from display ( probably touch + LCD controller ) to help here.