Hello @lduboeuf . When i saw https://open-store.io/app/batterysaver.lduboeuf , i thought first it was a GUI of this topic. Or could your app evolve towards this?

A bit different yes than always switching 2g/4g according tp screen state. But if i have 100 notif a day, it means 100 times the screen will turn on, i doubt it would be efficient...
But could be improved for sure

@lduboeuf

Would you release it on openstore ?

Maybe in the future, the ideal would be to have it integrated, but much much work involved + the fact that upcoming volTE will probably conflict with.

Is this for Xenial or Focal, or both ?

Focal only, only 24h a day

Would you release it on openstore ?
Is this for Xenial or Focal, or both ?

If anyone interested:
https://gitlab.com/lduboeuf/battery-saver/-/artifacts

source code:
https://gitlab.com/lduboeuf/battery-saver

the app can be closed after clicking "start" and if you see "Running...", it will create a background service

Edit: don't know if it is related but connectivity tends to have issue on upgrading to 4G. Or maybe only an indicator issue.

@lkroll Thanks a lot for your script, works like a charm !
As I said to @lduboeuf , I was wondering if it could be possible to add some exceptions ?
For instance, 4G could be maintained when the device is charging, or when hotspot activated, or even when an specific app is running (Futify for me).

Of course it should be possible but takes time. But would be better to look at the root cause, why LTE need so much battery. There are room for improvement, e.g we still don't manage the FastDormancy.

@lduboeuf I would have say if enable stay on 4G even if the screen shutsdown, but that's the idea.

ah ok but might not be related to my work around. It only toggles on 4G when request data and toggle 2G when data off.

@lduboeuf you're right I have no idea of what consequence it could have ! Thanks for your help !

To come back on the subject of this topic, would it be possible to add an exception when the hotspot is activated ?

Humm, what would be the bahavior for hotspot, if enable then auto switch to 4G ?

To come back on the subject of this topic, would it be possible to add an exception when the hotspot is activated ?

@lduboeuf said in [HowTo] Alternate way of saving battery when using 4G/LTE:

by mouting rw the partition and then upgrade.

do you have a tutorial ?

Well, if you ask, maybe you don't know the possible consequences ?
If ok then remount rw the partition: sudo mount -o remount,rw /
then sudo apt upgrade

by mouting rw the partition and then upgrade.

do you have a tutorial ?

@lduboeuf thanks for your 'dirty hack' !
after installing it says I have to upgrade, but sudo apt upgrade returns

Lecture des listes de paquets... Fait            
Construction de l'arbre des dépendances          
Lecture des informations d'état... Fait          
Calcul de la mise à jour... Fait                 
Get more security updates through Ubuntu Pro with 'esm-apps' enabled:                             
  libswresample3 libmediainfo0v5 libavcodec58 libavutil56 libopenexr24                            
  libsdl2-2.0-0                                  
Learn more about Ubuntu Pro at https://ubuntu.com/pro                                             
W: Verrou non utilisé pour le fichier /var/lib/dpkg/lock-frontend en lecture seule                
W: Verrou non utilisé pour le fichier /var/lib/dpkg/lock en lecture seule                         
E: Le répertoire d'archive /var/cache/apt/archives/partial n'existe pas. - Acquire (30: Read-only file system)

Any idea how to resolve ?
Moreover, is it possible to add an exception when hotspot is on ?

Well, your device must be up to date before doing any ubports-qa things.
You can either reinstall UT or go by mouting rw the partition and then upgrade.

Lecture des listes de paquets... Fait            
Construction de l'arbre des dépendances          
Lecture des informations d'état... Fait          
Calcul de la mise à jour... Fait                 
Get more security updates through Ubuntu Pro with 'esm-apps' enabled:                             
  libswresample3 libmediainfo0v5 libavcodec58 libavutil56 libopenexr24                            
  libsdl2-2.0-0                                  
Learn more about Ubuntu Pro at https://ubuntu.com/pro                                             
W: Verrou non utilisé pour le fichier /var/lib/dpkg/lock-frontend en lecture seule                
W: Verrou non utilisé pour le fichier /var/lib/dpkg/lock en lecture seule                         
E: Le répertoire d'archive /var/cache/apt/archives/partial n'existe pas. - Acquire (30: Read-only file system)

Any idea how to resolve ?
Moreover, is it possible to add an exception when hotspot is on ?

You must have a focal device on devel channel, then sudo ubports-qa install focal_-_PR_lomiri-system-settings-cellular_6

This will auto toggle LTE when cellular data requested , and back to 2G when off,
https://gitlab.com/ubports/development/core/lomiri-system-settings-cellular/-/merge_requests/6

( only work when toggled from the settings, not the indicator )

The greeter in focal is called "com.lomiri.LomiriGreeter" instead of "com.canonical.UnityGreeter". So i changed that in the script and tested that it indeed still works.

I placed the updated script in:
/home/phablet/.local/bin

#!/bin/bash

primary_preference="lte"
saving_preference="gsm"
sim_slot="/ril_0"

interface=org.freedesktop.DBus.Properties
member=PropertiesChanged

dbus-monitor --session "type=signal,interface='${interface}',member='${member}'" |
while read -r line; do
        if [[ ${line} == *"com.lomiri.LomiriGreeter"* ]]; then
                read; read; read -r line
                if [[ ${line} == *"IsActive"* ]]; then
                        read -r line
                        [[ ${line} == *"true"* ]] && /usr/share/ofono/scripts/set-tech-preference "${sim_slot}" "${saving_preference}" 1>/dev/null
                        [[ ${line} == *"false"* ]] && /usr/share/ofono/scripts/set-tech-preference "${sim_slot}" "${primary_preference}" 1>/dev/null
                fi
        fi
done

Don't forget to make it executable:

chmod u+x /home/phablet/.local/bin/lte-battery-saver.sh

Ubuntu 20.04 uses systemd instead of upstart so I created a systemd user service in:
/home/phablet/.config/systemd/user/lte-battery-saver.service

[Unit]
Description=LTE battery saver
Requires=dbus.socket
After=dbus.socket

[Service]
ExecStart=/home/phablet/.local/bin/lte-battery-saver.sh

[Install]
WantedBy=dbus.socket

Now to enable the service:

systemctl --user enable --now lte-battery-saver

Verify that it is running and up:

systemctl --user status lte-battery-saver

It should return active and enabled:

● lte-battery-saver.service - LTE battery saver
     Loaded: loaded (/home/phablet/.config/systemd/user/lte-battery-saver.service; enabled; vendor preset: enabled)
     Active: active (running) since Sat 2023-04-29 18:44:27 CEST; 1h 11min ago

That's it, now everytime the phone is locked the connection will drop to 2G and back to 4G/LTE once unlocked.
I tested and verified it on my Oneplus 5T, but it should work on other devices running focal.

I have used the "lte" modification in the script without success. Then I have reboot my phone and the script was working perfectly.

Thank you for the report, you have to use "restart lte-battery-saver" to apply script changes. I will add a note about it. It looks like "lte" is more generic then "any" so I'll change the script.

-> Final step : Reboot the phone

Reason : I have done the script II and I could not come back to 4G (2G was OK), so I have used the "lte" modification in the script without success. Then I have reboot my phone and the script was working perfectly.

@yoni said in [HowTo] Alternate way of saving battery when using 4G/LTE:

Here are the battery tests, starting with 4G with data on:

2G with data on:

When I see you plots without / with script, it is a day and night ! My Nexus 5 has a battery drain (or the battery is not enough powerful), I just installed the script so I lack of time to feedback but I hope results like yours, it would be wonderful.

Again, thank you very much for your kind help, such a topic shall be pinned I think.

Thank you for the scripts.
I found out that if the device doesn't have 4G you have to put "umts" in "primary_preference". (My device is e4.5 - Krillin - )

primary_preference="umts"

I've taken the liberty of sharing your scripts on my blog to reach more people, I hope you don't mind.

https://elcondonrotodegnu.wordpress.com/2022/04/25/scripts-para-ahorrar-bateria-en-ubuntu-touch/

Thanks again.