Following up on my recent update on the mapping project, I did actually find good flying conditions just a few days later and decided to give it a try with just two batteries. To make it work, I reduced the map coverage a bit and flew at a slightly higher altitude than normal (110m instead of 80m). This required fewer passes and thus less flight time, and was barely doable with two batteries. Not perfect, but still a success!
As always, the interactive maps are online at https://map.hafjall.is/ .