TetraSki is completely frozen/unresponsive
If the TetraSki appears to be totally frozen, with no joystick or sip-n-puff response, unable to power down, and remote LED showing disconnected, a hard power reset will need to be performed. This is done by manually powering down both batteries, which will kill system power, and then powering them back on and rebooting.
Follow the instructions for Powering down batteries for seasonal storage, followed by Powering up batteries from long-term storage.