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 in jeopardy.
The combination of a complex technical product, very severe consequences if done badly and the very limited amount of suppliers who produce in a responsible way, led Fairphone to the conclusion it was not able to produce batteries.
In the absence of complete documentation and information, and the possibility to visit the factory where these batteries are made, we are unable to approve or support third party batteries.
Fairphone values learning by opening your devices but we want you all to stay safe.
End of obligatory piece of text that is part of all topics in which people talk about putting unofficial batteries in their Fairphones.
Original Post
Hallo Kristin, der Einfachheit halber schicke ich diese Antwort auf Englisch.
After some search on the Internet, I found a suitable
while not perfect replacement battery for the Fairphpne 1:
It is the replacement battery for the Huawei HB5N1H. It
usually sells with an 1500mAh spec, but is also availble
with 1800mAh.
Akku für Huawei wie HB5N1H u.a. 1800mAh (800106317) - , - VHBW B2B Shop
This battery is somewhat shorter the the Fairphone 1 original,
but with a resilient spacer, it does perfectly.
So far, it works well.
Regards, Hermann
PS: gerne kann ich Dir detallierte Tipps bzw. Fotos geben.