I am trying to build a battery-powered application using the Feather 32u4. I need a timer to trigger every 120 seconds (although Timer1 with it's 8 second limit would suffice for the beginning), thus I tried using IDLE_MODE, which should save some power. Connecting the battery's 3V to the feather's 3V pin resulted in about 9mA power draw though, which is way to much.
Considering that the promised 0.3mA current in IDLE_MODE is still too much, what other options do I have to have a 120sec timer with ultra low sleep consumption?