Librem 5 | Temperatures and Runtime

A quick look at the Librem5's runtime and temperatures.

This video examines the thermal performance and battery life of the Librem 5 Linux phone, giving you an idea of what to expect in terms of heat management and how long the device can run on a single charge.

Temperature Analysis

The Librem 5's thermal characteristics are important to understand:

Heat Sources

• i.MX 8M Quad processor: Main source of heat during intensive tasks


• Cellular modem: Generates heat during calls and data transfer


• WiFi/Bluetooth module: Contributes to overall thermal load


• Display: Adds to heat generation when at high brightness

Thermal Management



• Passive cooling through the phone's body


• Software-based throttling when temperatures get high


• Hardware kill switches can disable heat-generating components

Runtime and Battery Life

Battery performance metrics covered in the video:

Factors Affecting Runtime



• Screen brightness settings


• Active radio connections (cellular, WiFi, Bluetooth)


• Application usage patterns


• Background processes

Typical Usage Scenarios



• Standby time with radios active


• Active use with web browsing


• Media playback duration


• Talk time on cellular calls

Monitoring Tools

Linux provides excellent tools for monitoring system health:

Check CPU temperature

cat /sys/class/thermal/thermal_zone*/temp
Monitor battery status

upower -i /org/freedesktop/UPower/devices/battery_*
Check system uptime

uptime

Improvements Over Time

Each hardware revision of the Librem 5 has brought thermal improvements:


• Dev kit: Initial thermal characteristics


• Birch/Chestnut: Improved thermal design


• Dogwood: Better heat dissipation


• Evergreen: Production thermal solution

Practical Considerations

For daily use:


• Expect warmth during intensive tasks (normal for any phone)


• Battery life continues to improve with software updates


• Hardware kill switches can extend battery by disabling unused radios

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