Running Out of Gas...

Hi Sarge,

The new tanks do not hold as much, as the rubber has not stretched out fully. Over the next half a year, you will notice it will take more gas each fill.

Its not wise to use the battery in this situation. If one cell is much lower than all the rest, it will experience a reverse voltage condition by the other cells in the battery continuing to driver current through it. This will damage it. Best to only use the electric drive to get the car to the side of the road, and then walk off to the gas station.

 

Driving on electric alone probably reduces total battery life by some fraction. But you have passed through the flames. Go, and sin no more :_>

 

There is a similar question at http://priuschat.com/forums/prius-technical-discussion/47479-ev-mode-vs-running-out-gas.html

Basically if you drive all electric when gas is available (like in the EV mode), the ICE will turn on as needed. If you drive on all electric on an empty tank the main battery will likely go down lower then it should. That could mean paying for a recharge at the dealer.

 

Great to heat about your experience Sgt... I always fill up around two bars. So far, I rarely would see over 400 miles with two bars left. Usually it is somewhere around 380 to 390.

 

I ran out of gas on my 3rd fill (after testing my theory that I could go another 35 miles at blinking, not quite.. 33 miles was all I could get) and coasted on EV 1/2 mile to a gas station and filled up. I have not tested this again and don't want to.

On that empty tank, I got 520 miles. My last fill was 501 miles and this was with the light blinking after I had started off to work (yes, I let it go past the two bars). Depending on where I am I fill anywhere from one to two bars and never get it to blinking except one a great while. So my fills go from 475 to 500, but never much more than 500.

 

There are lots of people who will tell you that you shortened the life of the battery. They know just as much as you. Nobody can tell if you did or didn't without -extensive- measurements. My "best engineering guess" is that as your battery is new it is very unlikely you caused ANY problem with it.

If there is fuel, you can discharge the battery to about 35% charge before the engine starts and recharges it. If there is no fuel (engine will not start) then you can discharge the battery to about 30% before the car's systems will "shut you down". Very little difference. As stated above, IF a cell (or perhaps a few cells) in the battery pack have slightly less capacity than the others, they will fully discharge first, and IF you then continue to discharge the pack those cells will be "reverse charged". This can destroy them. As your pack is brand new and still very well matched re cell capacity, it is very unlikely this would happen. If your car were, say, 7 years old, then perhaps it would be more likely.

You will have some stored codes you may want to erase, as some dealers use those codes as an excuse to either not do work they should, or blame you for an unrelated failure. Either an OBDII reader/code clearing device such as a "Scangauge II" or simple disconnection of the 12 V battery -ve terminal and application of the brake will clear the codes.

 

I must be old school. I cannot understand how anyone can run a vehicle out of gas. Regardless of the guessing gage, if you get to either 1/2 or 1/4 you should fill up. I know back home in Alaska I was taught by my father never let it go below 1/2 a tank. You also need to remember that your vehicle fuel pump is inside the gas bladder and the gas in the tank cools the pump as well.

 

My Prius has never taken over 8.5 gallons even when the blinking light was on.

 

Yep, that's typical. Embrace it. These days lots of people would be deliriously happy to go more than 300 miles between fillups.

 

Because, it does not let you drive in all-electric mode (without the engine spinning) above 41 miles per hour when gas is available.

 

Well, after 4000 miles I finally accidently allowed the gas gauge to go blinking. The weather was nice last week and I was switching back and forth between the Prius and my Sebring convertible (yes, top down on a nice Spring day @ 25mpg trumps 53mpg) and I lost track of the Prius gas situation. Drove about 5 miles after the flashing started to get to the next gas station (yes, I was nervous). It took 9.8 gallons, the most I ever put into it. So, I know I've got at least five miles on blinking, some comfort, but not enough for a highway situation were I may have ten or more miles to the next exit. I've been typically going to one blip, since my commute has a gas station about every five miles, but I am thinking now that the two-blip gas-up will become my standard.
That's my blinkin' blip story.
Mike

 

Refilling at 2 pips would be prudent. The bladder variability and MPG variation make it dangerous to assume that there is *any* particular amount left when blinking starts. One really just should not let it get that low.

 

hum.. my gas tank is slightly bigger than most of yours???
I have a 08 prius with 1800 miles on it so far, last tank the gas light started blinking at the last bar, I checked the manual and it said it has a reserve gas of 3 gallons??? Anyways, i believed the manual, and continued to drive for about 30 miles in mix 50% highway 50% city.. got to my gas station, and filled up at 11.3 gallons...

so what exactly is the "reserve tank"?? i know my VW had a 1.9 gallon reserve tank and it was pretty accurate.. since the prius has the funny bladder thing.. im lost...

 

Prius does not have a separate reserve tank.

Either your gas tank is bigger than most other Prius; or your gasoline station may have cheated you. Based upon the MFD odometer and mpg reading, did you consume 11.3 gallons?

 

On what page does the manual say this?

 

Wow,, It almost seems as if you have a malfunctioning gas gauge if within 10 minutes it went from 2 pips to 1 pip and you ran out of gas that quickly??

I keep seeing everyone say not to mess around and fill up when it gets down to 2 pips, but if it went from 2 pips to 1 pip and then totally out of gas within 10 minutes doesn't that almost sound like a problem with the gas gauge not really reading the tank level correctly??

Do you remember how long you were driving or how far you were driving on 2 pips before it went down to 1 pip?

This new kind of gas gauge measuring with the Prius is kind of weird and I am still trying to figure out what is 1/4 of a tank, if there are 10 pips, then 5 pips would read 1/2 tank, but then there is no way to see when it would be 1/4 of a tank, cause that would be 2 1/2 pips, but you cannot see a half pip or cannot even tell when it gets to a half pip before it gets down to 2 pips which would be less than 1/4 of a tank, but not by much.

Even if you go on a low estimate that the total space of the bladder tank is 10 gallons instead of the 11.9 it claims to be. That would be 1 pip for each gallon of gas. If the Prius is getting even 40 miles per gallon of gas at a very low estimate. You should still be able to go at least 40 miles when it goes from 2 pips to 1 pip in time to fill up and not worry about running out of gas.

So, for your situation, where your gauge went from 2 pips down to 1 pip and within 10 minutes you were totally out of gas. It still seems to me that your gas gauge is faulty??

What does everyone else think about this?? Do my calculations above make sense to anybody else??

It is really a shame that with a brand new car we have no idea how much gas is really inside the tank when that gas gauge goes up and reads full at 10 pips. At the very lowest estimate we should assume that 1 pip could safely equal 1 gallon of Gas.. Therefore, there should be NO reason at all that a person could within 10 minutes completely run out of gas when the gauge goes from 2 pips to 1 pip..

I would take it into the dealership and see what they say about this.

After hearing this, I think I am just going to be on the safe side and always fill up when the gauge registers 3 pips and not play with danger..

 

The gauge is just not very linear. On mine the first pip might last 150 miles, and the last less than 30.

 

okay so on page. 429 it says
Low Fuel Warning Light
Remaining Fuel (Approximately 3.0 gal. [11.4L, 2.5 Imp. gal.] or less)

It's not really a "reserve tank" but when the light comes on, from reading this, my assumption is that I STILL HAVE APPROXIMATELY 3 gallons? even if its 2 gallons, at 40 mpg.. i should be able to go 80 miles + ..

so.. none of you guys have this in your manuals?