Had my Bob 2 out today and was very apprehensive about it after loosing it last Saturday. All went well GPS locked and RTH worked the way it should have. One query I had. I let my Bop 2 battery run low in a safe area to see if the RTH would kick in but it didn't. Alarm went off telling me battery was low but it made no attempt to come home. Battery level was at 3% and I pushed the RTH button and it came home ok. At what battery level should it automatically return to home.