I have tested my 5 batteries finding out they are different from the residue percentage showed when they shut down (auto power off), there are around 20%,10%,8% etc. no matter they are old or new, I always bring anafi in sight when the battery is under 20%, and mark every battery recording their residue percentage for not falling off, wondering if it is possible to carry a power bank for prolonging the fly time for more photos and longer time-lapse footage.