• 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.