The one area where I feel Garmin devices are superior to their competitors is that they never lose any data. I've had crashes during a ride, but when the device boots up again, the ride is still there, ready to be resumed.
Today I started a ride with battery somewhat low. Midway into the ride, the battery was at 15%, and I started logging on my ForeRunner too, and enabled battery saving on the Edge. The Edge still showed signs of life almost until the end, but when I stopped to save, it was dead. I tried to power it on without connecting it to power first (this may have been a mistake), and it worked, but it shut itself off again shortly after.
After charging it a little and then syncing, the ride is uploaded with all the correct summary data, but with no GPS track. When looking at the actual FIT file in the Activities folder, the file is only 1.4 KB in size. That makes it rather hopeless to try to recover anything. I couldn't find any other files anywhere that looked like they contained a temporary version of the activity.
I know now that I should have manually ended the ride before the battery ran out. But I'm still curious if anybody else has experienced this and can explain why the device didn't save all the data.