Cellular Modem runs real hot, lots of battery

Ok. This is a bit of a shot in the dark, as I have been using the Librem5 as a daily driver for almost 1.5 years. (Awesome device.)

I frequently just turn the cellular modem off (much to the annoyance of my wife) because it runs so hot and I don’t want to waste all my battery, etc. That is my solution. I can get by with Dino and Wifi.

However, I do miss having my cellular modem on all the time. I could do that with my Android phone and Lineage OS. With the Librem5 I just assumed I had to turn it off to save battery and performance.

Any help on this? Should I try and update firmware? Is it the same for everyone that running cellular modem just means running hot and using a lot of battery?

As I said, the performance has gotten a lot better in 1.5 years but running the cellular modem still runs hot and uses a lot of battery. If anybody has suggestions or thoughts (be patient), I am all ears.

(I am cognizant that some issues are user-created and I am conditioned to just “do what I always do” without logic or reason).

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I don’t think that should happen. Since I received the phone early February I never enountered an overheating problem. One exeption, maybe: charging on a hot day in the outdoors. But that is hardly unique to the L5.

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Ok. Maybe it is more that, without a consistent signal, it gets hot/uses energy.

Does it change for you when driving, for example?

I have never experienced noticeable heat coming from the modem. Usually it’s the SoC that’s the main source of heat.

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What about notable load issues with the battery when in use? Can I test this?

For example, I talked on phone call for about 25 minutes the other day, using the cellular modem. That call drained maybe 40 percent of my battery. Is that normal? What other factors might contribute to that load and loss of battery life?

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On usability and UI side, it’s inconvenient that usage metrics, temperature and battery info are all in different apps or views. The three main aspects and their relation can’t be tracked (add to that, apps them selves - which ones are active an which are not). I’d really want to see them in one graph view, but none of the usage apps I’ve looked at do that. That would help in comparisons and to identify apps and use patterns that need managing. Any suggestions?

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Yes, all firmware. No, my cellular modem does not run hot, but I stay off-grid whenever possible so I never really get an accurate idea if it does or not.

I assume that the software is already up to date. That in turn will then raise the question as to whether you have enabled suspend, and I think that in turn will then raise the question as to whether the modem firmware is up to date.

Even on my iPhone, battery drain is higher when spending a lot of time in poor-signal areas (such as is common when driving longer distances in my country).

I guess the Librem 5 at least gives you the opportunity to run some hacky shell script to test a hypothesis that time in poor-signal areas correlates with rate of battery drain.

What about a day where you spend the entire time in the same place, while getting good signal? That would certainly be a more controlled environment to investigate in.

I wonder if the ambient temperature makes it worse? (Does it run hotter in Phoenix AZ?)

(And it isn’t just a Montserrat song by Arrow.)

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Yep, software up-to-date. I have enabled suspend. It works well. No idea if the modem firmware is up-to-date. How do a I check that?

Yep, it drains faster in poor signal areas. Thank you. That is a checkbox for me. The battery drain is much better when stationary and in a place with good, consistent signal. I was at my office in the city and that was much better than at home. Check.

I am interested in exploration of shell scripts and/or user tinkering with apps or operating system and their effect on battery.

I mean sure. The outside temperature does have an effect. No doubt.

Is it possible the modem isn’t seated properly and it could be working harder than it should? Just a shot in the dark here.

I can check. Thanks.

Here is what I am running for firmware:

firmware revision: MPSS.JO.2.0.2.c1.1-00032-9607_GENNS_PACK-1.351938.1 1 [Nov 26 2020 02:00:00]

Is this the most recent version?

It looks like this post is what I am really looking for: L5 Modem BM818 - Open Firmware

Although I am not allowed to hold my phone while driving, I do recall it becoming considerably warmer when I stream music on the road.
I don’t remember which part gets the warmest. But I will check it out this summer when we go on our vacation.

Ok. That is about what my experience is. Sometimes it gets so hot in the car that I can’t charge. Which is real annoying. The experience is not terrible. I just wish the battery performance was better when using cellular.

The Purism forums got restored to a previous backup snapshot, so if you have not already, email support@puri.sm about updating your modem firmware. If necessary, I can also forward you the same email they sent to me.

A quick report from my climbing gym: yesterday I streamed music for two hours (both cellular data and wifi switched on) without any noticeable temperature rise.
I know, this is not the same as streaming via cellular only, but I wanted to share the info anyway

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As an update to this. I update my modem firmware and I have noticed a significant improvement on: 1. my phone call quality has been improved and I think it corresponds with VoLTE better. 2. I think the performance of the modem is a little better in terms of consumption of battery. I have not real metrics to measure my beliefs.

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