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Linus67

My personal use of cell phones:

Calls + text messages: I want to be reachable at all times
I only use the browser, email, messaging apps, cloud services, and other apps when necessary (like a camera)

Most days, the phone is unused for 90% of the time it’s turned on. So for 90% of my usage, even a Nokia 3210 (with up to 260 hours of battery life) would suffice.

Task: Given this usage pattern, how can I maximize battery life?

Workaround:

Install and open “UT Tweak Tools”
For all apps: Prevent background suspension = ON

Location services = OFF
Bluetooth = OFF
Wi-Fi = OFF
Mobile data = OFF
G2 network (optional)

Then run the script in the terminal:
...
#!/bin/bash
#Enables power-saving mode on all CPU cores

for governor in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor; do
echo "powersave" | sudo tee "$governor" > /dev/null
done

echo “Power-saving mode has been enabled for all cores.”
...

New scenario:

The phone enters deep sleep mode after a few minutes
You remain reachable by phone and text message
Set alarms and timers function normally
Power consumption drops to an incredible ~22mA (Pixel 3a)

As a result, in this state, the battery level drops by only about 1–3% over a 10-hour period. (Tested on the Pixel 3a) Theoretically, a full charge lasts more than a week with minimal use. (see pritscreen)

Advantage: There are hardly any restrictions. You can turn on mobile data or Wi-Fi at any time and use any app with an internet connection. Afterward, turn Wi-Fi and mobile data off again.

Usage:
With appropriate usage habits, this can be the default mode. The reduced processor performance is barely noticeable. Only launching apps takes 1–2 seconds longer.

The cores can be restored to normal performance using this script.
...
#!/bin/bash
#Enables Schedutil mode (default) on all CPU cores

for governor in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor; do
echo "schedutil" | sudo tee "$governor" > /dev/null
done

echo “Default mode (schedutil) has been enabled for all cores.”
..,

It would be perfect if a “super power-saving mode” like that could be built into UT.

d4f0

@Linus67 Why do you want to prevent background suspension? I think for your use case it would be better leaving it off, it uses less battery.

Linus67

@d4f0

In the context of IT and apps (smartphones or PCs)
On mobile phones (such as Android or iOS) and computers, background suspension means that an app is temporarily frozen.

So, in this case, background suspension set to ON means the app is frozen.

Moem

@Linus67 said:

background suspension set to ON means the app is frozen.

But that's not what UTTT does. It sets PREVENT background suspension to ON. In other words, it sets background suspension to OFF.

For most apps on UT, background suspension is set to ON by default.

Linus67

@Moem
Yes, I thought so too, and it matches the description in the wiki. https://wiki.ubuntuusers.de/Ubuntu_Touch/UT_Tweak_Tool/

In my tests, however, the opposite was true. There might be another reason for this. I’ll repeat the test with different scenarios and log the power consumption in sleep mode.

-10 hours of standby (all apps with background suspension)
-10 hours of standby (all apps without background suspension)

In any case, battery consumption in standby mode (accessible only via phone calls and text messages + alarm clock function) can be reduced to a minimum. It feels like a Nokia 3210 with up to 260 hours of battery life, with the difference that modern smartphone features are available at all times.