@emro

coupla things:
1) 4% drop is the worst. happens to everyone, on every n9, if they do something battery intensive while the battery is fairly low. be at 20%, open the web browser, and do an image search. => 4%. its SO ANNOYING.
2) ive done extensive testing on power consumption of n9bm (on 5 different N9s). in all of my tests, power usage is exactly the same at rest (4mA ~ 16mA). im not telling you not to do your own tests, or not to uninstall it, just offering you info to help you diagnose your problem.
3) "devel-su", then "apt-get remove n9-button-monitor". thats how you remove packages. there are guis to manage openrepos software, but ive never used them.