FPU1 is charging, but percentage rise veeery slow

[Stefan]

I think your battery is probably simply worn out. Here is a possible replacement (without warranty!):

Generic battery to replace FP1 battery (see first post for warning)

This post contains instructions that can cause severe harm to you. Opening and modifying batteries is very dangerous. The battery is the most dangerous part of any phone. It has in numerous cases been linked to explosions, wounds and property damage. Just search on the internet and you’ll find them. Fairphone employees have seen with their own eyes the issues involved in the process of manufacturing batteries. The health and safety of the workers involved is very often i…