Hi there,
I have recently noticed when my Fairphone 3 battery reaches 15% appr. the phone shuts down saying that there’s no longer any power in the battery.
I have never changed my battery so it’s more than 4 years. Maybe it’s just normal? What do you think?
Claudine
Thanks @mde for your prompt answer. A dead battery is also my guess but I was wondering if it could be something else.
If you get a new one (and don’t know this yet:), it will live the longest if you keep it between 25% and 75% charge whenever possible (Ideally even a bit closer to 50%). It’s recommended to NOT let it run all dry to 0% as well as to NOT charge it to 100%.
Thanks @urs_lesse for the advice. I believe I might have let it drain to 0% more than a few times recently 
Just to be clear: While this is not ideal for the battery on the long run, it will not immediately destroy your battery, either. In your case it is most likely just “old age”. Four years is pretty good for a phone battery! By treating it optimally, you might make it last a bit longer, but in the end it will degrade nonetheless.
On top of that you have to keep in mind that the battery (and phone) are tools. If treating them optimally reduces their usefulness for you, then that is a tradeoff one might have to make.
By my experience, a phone battery shows this behaviour when it is completely worn out. It might still work for some time, but soon it will drop to zero from 30 %, 50 and more. In two cases, it was the reason that I could not use a phone with a glued in battery any more that would still have worked otherwise. My original Fairphone 3 battery still works fine after about 4 1/2 years. Aiming for a range of about 20 to 80 % seems like a good compromise, but can require an external / hardware timer when I don’t want to play around with apps that require root.
