@tvetter1976 If you use Pytrack/Pysense-controlled sleep, the PIC will power down completely the FiPy (it's not sleeping, it's completely off), stop USB, etc, and go to sleep. On a Pytrack you can choose to power down the GPS as well. Don't remember about the other sensors on the board. 3V3_Pymodule will be shut down. 3V3_Sensors can be kept on, though I don't remember if it's always on or if there's an option to shut it down as well. If you use machine.deepsleep, the FiPy will go to sleep, but I believe the Pytrack/Pysense will continue to work as usual, with everything powered. You probably need to take a few steps to reduce its power draw. Don't think there's anything in the libraries for that, you'll probably have to talk to the PIC and/or sensors directly, and I'm not sure there's a way to make the PIC go to sleep without shutting down the FiPy (though I don't know how much the PIC itself draws).