Will the CS Battery automatically discharge itself to a storage charge like the Inspire 2 batteries?

No, according to the specs, you must manually discharge the external battery to 45-60% for storage.

Just leave the CS in standby mode (just switch off the screen by short pressing the power button) and leave it overnight. That should bring the battery down enough for storage purposes then shutdown the CS (long press of the power button).

Sorry Andy, there is no auto-discharge function for CrystalSky's battery, please insert the the battery into the device and use it to discharge, sorry for the inconvenience.