Fairphones has a replaceable battery. Sometimes I would like to have a spare battery with me, to replace on-the-fly. In some situations, that is more convenient than to have the extra "dongle" known as an external USB battery pack.
The challenge is: How do you charge them? Back in the old phone days, you could have desk chargers for spare batteries. Another challenge: How do you carry external batteries safely?
So I got this crazy idea. Combine those two challenges! With an additional twist!
What if there was a portable "box" which could carry up to two Fairphone batteries, with a USB-C port to charge them. But! Let it also function as a USB-C battery pack which can be used with Fairphones (via cable) or other USB devices.
That gives you a portable battery charger, battery carry case for 2 batteries and a 3905 or 7810mAh OTG battery pack (based on FP4 batteries, depending on if 1 or 2 batteries are present).
If these cases can be designed to support more FP battery generations, you get something which could even be quite sustainable.
how do you carry your spare battery?
I did it inside the original plastic envelope that came when purchased. during some bike routes I did having my FP4 as GPS this saved my life.
how do you charge your spare battery?
what I did was:
every Monday I charged the FP4 to 100%
power it off and replace the battery
use the new battery the whole week until next Monday between 15%~20% and 80%~85%
so you have a spare battery during the week charged at 100%, if I used the spare I do the se steps whatever the day of thw week was