@Landshark , thank you. I'll have to look up the thread. The Volt won't let you operate the car in park (not sure about neutral) for more than 30 minutes to keep someone from parking it in the garage with it still running (neglecting to turn it off) and the ICE possibly starting up and causing carbon monoxide poisoning. I wasn't sure if the Clarity had the same safeguards in place.
I was going to post before that I doubt there's a timeout on being in "Ready" mode whether driving or parked, but now I wonder. I know cars nowadays are generate somewhat less carbon monoxide than old cars due to catalytic converters, so a 30 minute or so shutdown could well minimize the risk of doing so unintentionially (or intentionally trying to harm yourself). Still extremely dangerous to do so, of course.
You know, I wonder if the engine will actually start in Park in the first place? The only time I ever experienced any sort of driving power loss was just after getting this 2nd Clarity, my wife and I took a drive over an 8300 foot mountain pass (starting from sea level). We pulled off for a snack at a viewpoint on the climb back over, and sat in Park/Ready for ~10 minutes; the HV battery was already at or close to 2 bars at that point. When I accelerated away I saw 1 bar for the only time ever, and it was sluggish for a minute until the climb/acceleration let up a bit, then it seemed to charge up and ran fine after that, full power even though 2-bars. Now I suspect that in Park it lets the battery get to a lower threshold than it does driving, and I don't know if it would start the engine or shut down the car if you stayed parked longer.
To answer this and the original question, we need someone to do an experiment leaving the car running with everything off (lights including DRLs, climate, radio, etc) to see how long it goes until either the HV battery is empty and the car shuts down, starts the engine, or shuts it down sooner. It needs to be someone who can park outside with a relatively secure/private driveway, and who doesn't use the car many days because of COVID Work-From-Home. That might be me if I think of it one of these days. In theory if the overhead is only a few hundred watts it should last for well over 24 hours.
