Get rid of 'battery-low' popup after some delay?
That is hard-coded into the framework am afraid.

Look in frameworks/base/core/java/android/os/Power.java

public static final int LOW_BATTERY_THRESHOLD = 10;


The alternative is to roll-your-own ROM to do this, there's a broadcast intent for battery low warnings (ACTION_BATTERY_LOW) but that's only for system signed apps AFAIK and cannot be intercepted.

The alternative is to listen for the ACTION_BATTERY_CHANGED broadcast and perhaps using Tasker, just to mute the battery warning sound...