Theoritical lowest current drain in sleep

Hardware Librem 5
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I stumbled over this to me it looks like the codec is always-on. This raised the question my head: what is the lowest possible power consumption when librem-5 is in suspend

Probably the codec can still go in suspend. But when you make the list of hardware components and given the sdk fully supports every components sleep mode, what is the lowest possible current consumption?

Is there maybe somewhere a list where this is all documented?

To be honest, the runtime of the librem-5 is not as good as I hoped. I don’t want to start a flamewar, but this is something that android kernels enforce pretty successfully to the hardware vendors.

Maybe already the imx8 is the bottleneck. https://www.nxp.com/docs/en/nxp/application-notes/AN12118.pdf gives a few hints about deep sleep mode current consumption. It’s complicated…

So what’s the theory about minimum power consumption on librem5?

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Dynamic-Ram still not enabled on Librem 5, so that will help a lot to save more power and performance. Also OpenCL will arrive this year to Librem 5 this will help a lot to save power. Online video hardware accel will arrive this year to L5 so this will help a lot to save power. The modem maybe will get some more power save too. GLES3.0 will save power too. A lot more. So Librem 5 still not finished.

Edited: Pipewire and Wireguard will help to save power in Librem 5 also white theme too :wink:

Edited1: Librem 5 already working a minimo consumption before crashing the cpu on Inactive Mode(screenoff), however on sleep(S2R) Redpine y Ram still on medium consumption of energy. I hope i responded enought…

Stay Purism!

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True, but keep in mind that the Librem 5 is essentially just a very small “laptop,” so its battery performance is more similar to a computer’s.

Of course, it’s marketed as a phone, and it will be used as a phone, so it does need to be at least as good as regular smartphones.

I think it will get better with the improvements that @carlosgonz mentioned, and as the suspend function improves (and hopefully starts behaving like a power-saving smartphone).

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For a start you would operate the kill switches in order to turn off power to those components. But is that acceptable to you? Does that align with your pattern of use?

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Battery: 4500mAh
Current runtime with sleep: ca. 20h
Average current drain: 225mA; @ca. 4V → 900mW

There is a handy component list.

How do the 225mA/900mW assemble:

  • BM818-E1: ? (why is there no proper datasheet available!?!)
  • iMX8 quad: deep sleep with MIPI-CSI: 105.476mW
  • Hall sensor AH3663: 8µW
  • STM32L432KC ca. 3µA in Stop mode
  • Ambient light STM32L432KC: ca. 780 µW
  • GNSS 17µW
  • Codec
  • Wifi
  • …
    The list could go on and on.

Maybe it could be visible where the librem-5 could end up regarding low-power-consumption. Then this can be compared to the current drain. Then one could look up the lowest hanging fruit in the list: That is finding the component that does not do sleep/standby; Check what could be the reward; Then try to make it work. Eg. Hall Sensor has no big power saving potential (low reward) but might be easy to add.

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