App run in background?

So I made an app that sents me a notification whenever my phone has 3% battery. However, the app only works when the app is on, which makes it's service useless. Is there some way I can make it work in the background? I tried using the KeepAlive extension but it doesn't seem to work. Any tips on how to make it work please?

You could use


I would certainly like to, but I don't really want to pay especially for such a small app that I am trying to build.

you could try Tasker


Trying to push the limits! Snippets, Tutorials and Extensions from Pura Vida Apps by icon24 Taifun.