Hi Alex,
Thank you for your reply! Mine is a bit late, but it was very helpful. I have tried the settings you suggested and ended up using the 10 minute cycle and an amplitude filter of 1024. I set the frequency filter to 20 kHz. There wasn't much trouble with background noise and I worried that a 40 kHz filter would remove bat species with lower frequency calls.
These settings lasted for at least 12 nights so far with lithium batteries, and very active bats.
I noticed that expanding the file significantly increased the size. This is not a problem for me, but might be good to know if that is a restriction.