Since my s6 updated in the last two weeks it's started coming up with battery notifications, not the usual ones u get at 15%and 5% but ones at random percentage, 22% and 14% (but not always these)
I've got a screen shot which I'll post, I just want to get rid of them if I can
Personally, i don't like going below 30% but 20% is the lowest I take my battery. I also use Accubattery from the Play store and don't charge the battery above 80% as much as possible to keep my battery as healthy as I can.