Running on Empty.......

Some folks will get 250,000 miles on their hybrid battery, others will get 2.5 miles, once. Your choice.

Besides ruining the HV battery, you risk several fuel system problems lean mixture due to the compressibility of air, fuel pump overheating, computer lockout due to failure to start, etc.

While I am sure being stranded by the side of the road has it's charms, here is my very best advice

If your mother in law is in the car, get gas at 3 pips, you would never live down leaving her in a non-air conditioned car while you went for more gas (3 times, my Prius does not recognize less than 3 gallons)

If your wife is in the car, get gas at 2 pips, same reason, just less ridicule when you run out.

If you are alone or riding with a friend who can keep his mouth shut, get gas at one pip

If the last pip starts blinking, GET GAS NOW. My gen 2 Prius once ran out 7 miles after the pip started blinking. (Other times I had gone over 30 miles, it is not consistent)

 

Interesting. I think 2.5 miles is probably the max range. Being at highway speed when fuel cut happens makes all the difference. Since 52 mph represents 3 times the kinetic energy, but less than 3 times the moving resistance, I seriously doubt that you could get 4 miles at 30 mph.

This is not something to do regularly. It is hard on the fuel pump.

 

I think you answered my question, the real gas tank
capacity for the Prius C is not 9.5 but over 10 gallons.

 

That 9.5 is fiction. I put in 9.77 yesterday with out topping.

 

So we can see how good is a Prius C. Enjoy your new toy.

 

This all sounds eerily similar to the "Here, hold my beer and watch this!" crowd.

Good luck with all that.

 

As mentioned above, the fuel pump is a concern (and a big one considering it's probably all integrated in the tank).

I had an '89 F150 with dual tanks for several years. While towing one of my cars one day, I forgot to switch fuel tanks and let the rear tank run dry (the fuel gauge didn't work for the rear tank). After the next fill-up, the rear pump would only put out a dribble of fuel.

A few weeks after replacing the pump, I let a friend use it to move a bunch of stuff. He did the same thing and sure enough, another pump died.

The 3rd one I put in was an official Ford (Motorcraft) pump. It lasted until the rear tank generated a leak from a piece of shrapnel on the highway.

Finally, my grandfather had a Civic a few years ago. Due to an inexperienced driver running out of gas, the fuel pump went out within a few days.

Now, I always put fuel in the car when the warning light says so. Especially on a car where a fuel pump will probably be a very costly fix.

 

Fuel in the tank also lubricates and cools the fuel pump. Running it dry can easily damage it.

 

Imagine a ballet dancer doing a complicated dance, the computer constantly balancing MG2, and the ICE to smoothly give you seamless control.* Now cut off one leg. (this is different than just doing a pirouette on one leg) The dance fails.

You have run out of gas, but the computers are still trying to start the ICE, the fuel pump is still pumping, but no gas is flowing to cool it. Soon the computer will realize that the ICE is 'broken' and immobilize it. (you will need a tow to a dealer) Meanwhile having no other 'leg' the battery is doing tasks it would NEVER be asked to do if the ICE worked. So heat is building up in the protective case much quicker than normal. And the battery cannot protect itself like it usually does as there is no other motive force and you may be in an intersection with an 18 wheeler barreling right at you, so it keeps trying until destructive failure. (The owner wisely omits telling Toyota he destroyed the battery himself, there is no warranty in being honest)

And you are confused by how that was different than the engine shutting off at idle. Sigh.


*Under rare conditions, MG1 is actually a motor aiding propulsion, but let's leave out heretical mode.

 

What kind of lousy computer programmer writes a program that keeps the fuel pump working even after it has been determined that there is no more gas?

 

All that the computer knows is that the ICE failed to start once. When it fails to start 10 times, then it quits trying to use the ICE and you have to tow it to a dealer to try the ICE again.

"You are such a lousy programmer, you could not program a VCR to blink 12:00" easily the best insult I ever heard, I swear it was not about or by me.

 

So there are computers all over the car calculating every aspect of fuel consumption including tank fullness and miles per gallon, but the computer controlling the fuel pump has no access to any of this information?

 

If the same programmer made the engine shut off completely where there was still 1/2 gallon in the tank, but the sensor couldn't detect that you could make the same argument.

The car gives PLENTY of warning before running out of fuel (noises and flashing indicators), the driver chooses to ignore it.

I am a developer by trade and we have a saying: "There's only so much stupid you can program around"

 

You are making the assumption that some computer controls the fuel pump, it may well be on any time the car is ready. If it was turned off and the computer wanted to start the ICE, there would be a delay while pressure builds. By running it all the time, the ICE can start more gracefully.

 

That goes right along with " 'Idiot proof' is impossible, idiot resistant is the best you can hope to accomplish."

 

So you think it is too much time spent getting around "stupid" if you set up some code that would alert the driver and refuse to activate the fuel pump until some kind of override was detected, or until gas was detected? You weren't a developer for MS-DOS by any chance, were you?

 

I guess there would be some weighing and deciding between the value of running the pump all the time so that the ICE can start gracefully, as opposed to not running it all the time to prevent the occasional fuel pump damage from lack of gas. Perhaps consistent graceful starts on all vehicles would outweigh saving the rare, mistreated fuel pump.

Still, one would think that eventually a design would come along that both provides consistently graceful starts AND protects fuel pumps from being damaged by empty gax tanks...