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