How long can the Argon last on battery with default or near-default firmware?


#1

If I want the Argon to read from three analog sensors that use 0 power (just assume 0) every 5 minutes, how long would the Argon last on a 2200 mAh 3.7V battery with the out-of-the-box firmware? Or lightly modified firmware? I tried looking for power consumption in the Argon datasheet but did not find it. I’m hoping for a month of battery life out of the box…or close to out of the box.

My perception of the Photon was that it didn’t have a low power mode and any engineer that wanted to activate low-power mode had to read Broadcom source code and implement it himself. Is that still true with the Argon?

I’d like to keep the following features:

  • Uploads data once every hour over Wi-Fi unless queried live
  • Ability to update firmware OTA

#2

Why did you think the Photon didn’t have low power modes?

https://docs.particle.io/reference/device-os/firmware/photon/#sleep-sleep-

I’m not sure if you’d get a month from a 2200 mAh battery with hourly updates, but you might. I’ve got a project using an Electron and a 2000 mAh battery, and it lasts about a week. My update times are variable, though. When it’s in motion, it updates every minute. When idle, it drops to every 15 minutes. And at night, from 9pm to 6am, it drops to hourly. I just did a quick check of some of my logs, and it looks like it was averaging around 400 published events/day in some cases.


#3

The power consumption of the photon is totally driven by lighting up the wifi. If you look at the reference documents then in normal sleep it will draw 1mA (where it can wake itself and then repeat sleep). Lower consumption 80uA is possible in deep sleep mode but an external wake signal is required and the device will restart/reset. When wifi is on current will be between 30-80mA with some spikes. Hence, very short wake periods with quick wifi comms and long deep sleep periods could get reasonably long periods of battery life - weeks.


#4

If you’re interested and have time, I wrote a long in-depth blog post series on low-power wifi: https://blog.voneicken.com/projects/low-power-wifi-intro/

The tl;dr; is that assuming the esp32 app does all the right magic things and tweaks heavily for low power use and your wifi environment is quiet then you might be able to get ~20 days out of a 1000mAh battery as a back-of-the-envelope calculation.

In order to maintain an association and remain “connected” the esp32 has to wake up every Nth beacon (typ 3-5) and check whether the AP has a packet for it. If it does (if you app is idle this is often some LAN broadcast packet) it has to wake-up to retrieve the packet and then lingers with RX on for ~50ms @120mA. So your actual results depend heavily on how the “light sleep” mode is configured and how much broadcast is happening on your network.

Overall, my prediction is that you’re going to have a hard time eeking out a month of run-time on 2200mAh given all the unknowns.


#5

Thanks for the link to System.sleep. I read that once before and forgot about it. I didn’t see a “System.sleep” in the Photon examples so I just assumed it didn’t exist. I’ll test it out on my Photon and observe the power consumption


#6

Not sure where that comes from - that is true for the Argon but not for the Photon.
The STM32F2 powered devices (Photon inlcuded) do feature a real time clock that can wake the device on a schedule. While previous device OS versions had the problem that inadvertent HIGH signals on the WKP pin at the moment of going to sleep caused the scheduled wake to fail this has been addressed with a more recent fix which allows you to deactivate the WKP pin and hence interfering with the scheduled wake.


#7

My bad - photons can wake after a time in deep sleep - I splitting my thinking with the mesh/gen3 devices.