Extend automatic poweroff function

I have an Android tablet which I use as navigator in car. It has feature to automatically shut down device when power disconnected after delay in 10 seconds. I want to extend this delay to 30 seconds or more. I searched Android settings and found no related settings for this delay, then i decompiled SystemUI.apk with AndroidMultitool and found power disconnected message in AndroidMultitool/Decompiled_apk/SystemUI/res/values/strings.xml

Code:

---

    <string name="power_disconnected_message">Power disconnected, will power off soon.</string>
</resources>

---

I may only edit this string, but i want change poweroff delay.
I have attached decompiled SystemUI in zip and screenshot showing warning message with counter.

Attached Thumbnails

 

Attached Files

SystemUI.zip - [Click for QR Code] (1.20 MB)