🔋 X4 Pro Battery: Test Results & Observations

I wanted to understand what actually affects X4 Pro battery life and it's consumption patterns, so I tested it during normal reading under several conditions over the past week and compared the results with my X3 and X4.

🧑‍🔬 Test conditions

I have all of the three devices running Crossink 1.5.1-RC4,l. I measured approximate battery loss per hour while reading under three X4 Pro configurations:

- Frontlight OFF + Touch OFF

- Frontlight OFF + Touch ON

- Frontlight 50% + Touch ON (both warm and cold gauges in the middle)

I also observed overnight sleep consumption, highlighting behavior, and the discharge pattern across different battery levels.

⚠️ These are real-world measurements rather than controlled laboratory tests, so the numbers should be treated as approximate.

📈 Measurements for X4 Pro**:**

- Light OFF + Touch OFF: ~2%/h

- Light OFF + Touch ON: ~2.5%/h

- Light 50% + Touch ON: ~8%/h

- Sleeping overnight: ~0.5% total

For comparison, under my normal reading:

- X4: ~1%/h

- X3: ~1.5%/h

- X4 Pro: ~2%/h at its lowest-power configuration

💡 Interestingly, the X4 Pro has a much larger 1100 mAh battery vs 650 mAh on X3/X4, yet currently consumes a larger percentage per hour.

🔬 Finding 1: Frontlight dominates consumption

Touch itself has a relatively modest effect: 2% → 2.5%/h. But enabling the frontlight at 50% takes consumption to: ~8%/h. So the frontlight is by far the largest power variable I've observed.

🔬 Finding 2: Battery % isn't linear

The displayed percentage doesn't seem to decline at a constant rate:

- 100–80%: faster

- 80–20%: noticeably slower

- 20–0%: faster

The first discharge cycle was also the fastest. On subsequent cycles, individual percentages seem to hold longer.

💡 My interpretation is that some of this may be battery gauge/calibration behavior, rather than actual energy consumption changing that dramatically.

This makes short tests misleading. I wouldn't take a 5–10% drop and simply extrapolate it to 100%. Longer tests, particularly across 80–20%, seem much more representative.

🔬 Finding 3: Highlighting matters

Highlighting can be surprisingly expensive when done frequently.

- More efficient: select first word → tap last word

- Less efficient: select → drag across the passage

Dragging continuously changes the selection and causes multiple intermediate display updates as you move through the text.

💡 For heavy highlighters, those updates add up. This also means that "one hour of reading" isn't necessarily comparable between users: passive reading and interaction-heavy reading create different workloads.

🔬 Finding 4: X4 is still the efficiency champion

My observed reading consumption:

X4 ~1%/h → X3 ~1.5%/h → X4 Pro ~2%/h

The X4 is clearly the battery beast in my testing.

💡 I suspect the clock/background activity on the X3 may partly explain why it consumes more than the X4, but I haven't isolated this, so that's a hypothesis rather than a finding.

🏁 Conclusion

- The X4 Pro's biggest battery cost isn't touch; it's the frontlight. Sleep consumption, meanwhile, is excellent at only ~0.5% overnight.

- The X4 Pro is also still a very new device. I believe CrossPoint and CrossInk will continue improving background activity, display/touch handling and power management as their X4 Pro support matures.

⚠️ I'd consider these results a baseline of the current software, rather than the final potential of the hardware.