out of gas , getting out of safe mode

Cool, so it's all just about the risk of running out and dying in the cold.

What is the reward for taking that risk?

What about this scenario, you are down to one pip, about to turn up your driveway and it starts flashing. Not a problem, get fuel tomorrow.
Spouse wakes with stomach cramps which are severe and asks you to run her to the hospital.
Do you fill up on the way or risk it?

 

Some people think that life will always go according to their plan. They aren't concerned about maintaining a fuel reserve.

Others have lived long enough to see unforeseen emergencies and natural disasters happen. Those are more likely to "be prepared". Being in this latter group and having a "belt & suspenders" attitude anyway, I look for gas at 5 bars showing.

 

Exactly. As a pilot, I learned an old saying: "The three most useless things in the world are 1) The altitude above you; 2) The runway behind you; and 3) The fuel you didn't put in the plane.

It works for cars too, except the altitude part.

Tom

 

As the last pip starts to flash I have fuel for at least 80km maybe even twice as far. Our hospital is 2km away, I can rest easy. However, I take your point, if the hospital was 40km away I would turn around and fill up immediately.

 

Do you also carry around TWO spare wheels? As soon as you get one puncture you're running without a spare.

 

No, but I will repair or replace the failed tire the same day that it fails, rather than continue to rely on the skinny little spare.

 

Me too.

 

You can drive a limited distance on battery power but we're talking about a mile or so. More if you can reduce your speed to about 18-20 mph and minimize all electrical loads including heater and AC. Less if you try to drive faster and keep all of the accessories running.

I treat running on battery as "getting to a safe place" energy unless I see a service station right ahead.

I've never run the battery to car stop but that is what happens. Do NOT try to restart car until some gas is put in. As the original poster pointed out, repeated attempts to start will set a code that requires a tow and reset at a Toyota service center.

Bob Wilson

 

I've never understood why folks will push a car to the last pip. What could you possibly gain?? The difference in weight will result in microscopic difference in fuel consumption

Having real world experience in survival and/or combat situations, there is no f****** way I'd box myself into a corner by having a vehicle on fumes. At the very least, even if you don't have to worry about bitter cold and freezing to death, you *do* have to worry about unfamiliar gas stations and muggings/carjackings

In winter, I get nervous if the gauge drops below 3/4 fuel. In summer, I like to keep it over 1/2. The extra "cost" to doing so is zero.

Seems around here, during every major blizzard when portions of the Trans Canada are closed, stranded motorists are crying for help, due to running out of fuel. If it's a truly bad blizzard, they may even run out of fuel. You don't last long at temps of -25 C and colder, exposed to the elements, with no heat

Winter driving to my hobby farm, I carry a snowmobile suit, and a sleeping bag, along with basic emergency supplies. It may not be very comfortable in a snowsuit and sleeping bag, but I won't freeze either

As far as the comment about having two spare tires, yes, in some situations, you had BETTER have two - or more - spare tires. Eg, driving on Outback roads in Australia, remote northern areas of Canada, the nearest tire shop might be 200 km away

 

Huh? Mine will go 1.1 miles on the top blue bar (the target SOC) on the flat, and that is accelerating from a stop to about 30 mph. I know because I've done this at least a dozen times in both directions. It uses a little over one full bar. One of these days I'll get around to testing a 2+ mile run. The trick will be in keeping the engine from kicking in as the bands tighten while charge drops.

Considering the battery capacity is about 1.3 kWh with about less than half of that available it makes sense that the effective range on the flat should be a few miles, as long as one drives very slowly and conserves the battery. Seems like the simulator calculated 250 kWh effective at highway speeds, so about half as much at 30 mph should be in the ballpark. Assuming one could use only 20% of the total charge the range would still be 2 miles.

Climbing a hill would be another matter (descending one would be no sweat of course.) And one should immediately shut down all but critical accessories if this were too happen, starting with climate control. If you need lights or wipers continue to use them--flashers should be on though if the prevailing speed is much higher.

Range should be more if one is already at highway speeds.

 

I'm trying to give a safe lower limit to save people from themselves.

Depending on speed, traffic, temperature, battery condition, driving technique, terrain, and the phase of the moon.

Range on the battery alone is about 7 miles if you drop your Prius from an airplane at 37,000 feet; more if you consider any forward velocity component.

Tom

 

Where are you at that you worry about filling at 5 bars? I can understand if you are getting ready to make a long haul through the desert with no stations along the way...or in a long sparsely populated rural highway in cold/wet weather.

Perhaps the smartest thing to do is to determine the lower indicated limits without trouble (in good conditions) so that one knows better what the range is. I've done this on every vehicle I've owned, pushing tanks ever lower with the expectation I might run out, then filling. That lets me reset the 50 mile cushion somewhere near the bottom indication. I've never run out of gas this way and I can accurately estimate what locale I will use for fill ups with that cushion still intact. I find that much more reassuring than getting nervous at half a tank! I prefer to calibrate my instruments in the real world, rather than to be stuck guessing about range and such.

The problem with a Prius appears to be that folks have trouble getting 11 gallons in it even if they run it out. This is well below the stated capacity. On other vehicles I've pushed right to the stated capacity before without running out. If I filled at 5 pips the effective range would be 250 miles if I was lucky with the prior fill.

With an 11.9 gallon tank I shouldn't have to worry at all about a 10 gallon fill since I always do full tanks. Yet at 1 pip the MAX I've gotten in was 8.9...and sometimes only 7 gallons. So it is tiime for me to start checking out the flashing pip.

Consider this: from what I've seen of crime reports you probably take a much greater risk with the more frequent fills than you do with calibrating your tank to get better range and risking that you might run out once.

 

In normal driving I always start thinking about refilling at 5 bars. The gas station where we live charges tourist prices, as well as most of the other stations in the county. We have to go into Traverse City to get semi-reasonable gas prices. If I don't refill at a half a tank, I often find myself without enough gasoline to make it back into Traverse City.

Besides the economy of buying at a cheaper station, there is also the issue of safety, especially in the winter. Having gas in the tank may make a life or death difference if you get stranded in the snow, which is very easy to do up here.

Tom

 

I'm wondering whether or not repeatedly running a car out of gas ought to void the warranty. In fifty years of driving, I have never run a car out of gas. These days, I am seldom low on gas because I buy whenever my route takes me near someplace with a good price. What is the attraction of running it out anyhow?

 

Filling at half a tank has nothing to do with getting nervous, this is what I practise with my work car, a 6 cylinder Holden Commodore.
There are 2 reasons I fill the work car at half a tank.
1/ Operational preparedness, I don't need to worry if there will be fuel in the car when I need it.
2/ The gauge in the Commodore is much worse than the gauge in the Prius. I may get 400km out of the top half of the tank but the bottom half will vanish in 150km.

There is another reason but that is paranoia, I ran out just after I got this car as the gauge wasn't calibrated correctly, it went from 1/4 of a tank to flashing warning in about 15km then ran out in less than 2 more km. This has since been fixed.

I will allow the work car to go just below 1/4 if I am on a long trip and have a preplanned fuel stop strategy.

Now I have explained that, please tell me the gains you make filling up 40 miles after the blinking warning starts flashing?

 

I generally have never let my gas tank get below half in any car, and the lowest I got in the Prius was 2 bars (on a 300 mile journey, with gas stations as far apart as 50 miles or further). If I'm in the city, I worry about being stuck in a traffic jam. Even in a Prius, a traffic jam can get your fuel economy REALLY low, and so can slurp up the gas in no time; would you like to be stuck in a traffic jam with no gas? How about in the summer, and with no A/C because your car won't work? Or the winter with no heat?

In any case its well documented that the Prius gas gauge is flimsy so all precautions should be taken....

 

No worries on that front; the "major" city closest to me is Mission Viejo, CA and the crime rate there is quite low; in fact I think it has the lowest crime rate for cities of 100,000 population or more.

I just like the idea that I have a relatively full gas tank and am ready for any eventuality.

 

Well I've been through Houston's horrible traffic jams and never been in any danger of running out of gas. Now, my wife was unable to get out of the city with a full tank of gas during the Rita evac, but that's because Texas' evacuation plan sucked a** and the idiot mayor told everyone to evacuate rather than just those of us in zones that were "mandatory." So the full tank didn't help either, and she had to abandon the evacuation. When particularly nasty weather is forecast I fill up.

I'm not really worried about sitting without AC in summer. I ran regularly at lunch on humid 110 F days. So a hypothetical about going a few minutes without AC really doesn't concern me. In winter, now that I'm back in the midwest I use the heat very little (dressing for the weather) and I'm not inclined to sit in a car waiting for help anyway. Then again, I'm not the type that thinks he must absolutely go somewhere regardless of the weather.

If it proves to be that inaccurate and isn't fixed pronto I'll probably sell it. It's a reliability issue. I didn't buy a car with a 5 gallon tank and a sub 250 mile range. If I have to treat it like one, then it doesn't suit my needs and it has to go.

I plan for continegencies and give myself some margin. And we're talking about a margin here that should be about an hour's worth of gas at minimum. Driving around having no idea how much gas & range you have left, now that scares me.

 

Unfortunately, the very smart Prius is very dumb in the case of running out of gas and will keep trying to turn the ICE over (in an attempt to start it) when it runs out of gas and it uses battery VERY quickly. Imagine constant B mode with no fuel. If you're at highway speeds the HSD must keep the engine spinning to keep MG1 from having to spin backwards WAY to fast. See Toyota Prius - Power Split Device for reference.

I learned all of this the hard way 5 days after getting my new Prius. My first Prius had a very reliable gas gauge and I assumed (wrongly) it would be the same with my new one. With 2 bars showing the new Prius flat ran out of gas at 60 mph. An exit was about a mile away and I made it to a station right off the ramp. Having since found this site and read the insights of many experienced owners here, I have learned how lucky (and stupid) I was. Now, two bars finds me at the station every time.

 

1. Yes, Ray is an idiot in this case (and others who flirt with running out of gas except under test situations). This can definitely reduce the lifespan of the battery.
2. The ScanGauge will read and clear the codes. It also can estimate number of miles left on the tank if you have it set correctly, but it doesn't handle tenths of gallons for tank size, so it won't be exact.
3. The gas tank is a bladder (for emission controls, at least for U.S. cars, possibly Canada too), in cold weather it won't hold the full 11.9 gallons, and I wouldn't count on it holding more than 11 gallons under any scenario, you need to have some margin of error.

Personally, I get down to 2 bars and then refill. I haven't had an issue with the accuracy of the gas gauge, but I don't track it by the decimal point either. Gas stations aren't too far away here. I generally get 40 miles or so to a bar in the winter, so even if I get caught out in a blizzard this would give me over an hour of driving time. When I'm driving to northern MN I need to plan ahead a bit more, but on the highway I should get 50 miles to a bar (conservatively) and getting stuck in traffic is never an issue.