Service of an app stops when phone is not being charged

Question

My Activity starts a service by calling startservice(). To simplify my problem lets say the service will be a counter, and the counter will be increased in ever

Answer 1

You need to hold lock if your service has to be running in the background

PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
PowerManager.WakeLock wl = 
                      pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "My Tag");
wl.acquire();
// when you done
wl.release();

Better way is to use AlarmManager because keep the service running all the time will drain the battery and waste the system resources.