What happens when you run a Prius out of fuel?

I ran my Gen 3 out of fuel years ago, and I was surprised when the engine finally died at 181 kms, after the red indicator came on. The car would still limp along at about 30 kph. I have no idea how far this would have got me.

My Gen 5 behaves as follows:

The red refuel indicator comes on with 40 kms remaining on the fuel range indicator. A message, "Refuel" shows on the console about every 10 minutes.

When the fuel range indicator reaches zero, the range is replaced with the word, "Refuel." The console message no longer appears. At this point, I set the trip meter to see how far I got before the engine quit. The car does not switch to EV mode when this happens; it just runs on the battery, which had more than enough charge to get me home.

The engine finally died at 99.8 kms. This is the message:


Overall range after first "Refuel" warning, ~140 kms.

 

I was at the end of a long road trip, and I had fully expected to run out of fuel along the way, based on the distance to home and the indicated fuel range. I recall seeing "233 kms to home on Google Maps, and 103 kms fuel remaining." I had kept more than 40 kms EV range as a reserve.

As it happened, when I got home, I still had fuel, so I took an extra excursion to see when I ran out of fuel. which turned out to be about another 30 kms. Quite a surprise.

 

I didn't have to refuel this time.
I had over 40 kms of EV charge.

I used to carry a plastic fuel can, but it always leaked a little, and smelled up the interior.
I ordered a metal fuel can, and it doesn't leak any vapors if the lid is kept tight. I know that some cops frown on carrying a fuel can in the car, so I keep it in the cardboard box it came in.

 

As you may know, I ran my fuel tank bone dry doing a total range test.
I filled the tank today, and the amount was 40.022 L, or 10.5 US gal. or 8.8 Imperial gal.

 

I never quite understood the difference between HV mode and HV/EV mode; it seems to switch between them on its own. Anyway, when I ran the fuel tank dry, it was in HV/EV mode, and the energy flow diagram only showed power flowing from battery.