I have not seen any discussion of how the car would function if it were completely out of gas. Would the car function normally at low speeds? How far would it go? How fast could it go?
It is drivable, without gas, for very short distances on battery alone. This is NOT recommended and can damage the car, the battery and may void the warranty for any damage that occurs when you do it. If you run out of gas while driving it's a nice buffer to safely get you off the road, but do not push it to battery exhaustion.
Member Join Date: Nov 2005 Location: Buffalo Grove, Ill. Posts: 68 My Car: 2005 Prius Package: #4 (I must preface this bysaying it happened last year) Well it happened, Yes my friends i ran the Prius II out of gas. Partially on purpose, but i wont do it again. Comming home on 294 (chicago guys will know) about 12 miles out of the Ohare oasis (northbound) it kicked and started slowing down, (let me preface this by saying the last gas bar was flashing) all the lights on the dash lit up like Christmas. It slowed to about 40mph and ran well at that for about 4 miles or so then it slowed to a crawl and then stopped. I sat with the flashers on for about 5 min then started it up again, and away i went up to about 25mph or so into the tollboth and asked how far to the next gas station,? she said can you make it 10 miles to the oasis,? i said i do not know! lol but off i went. about 8 miles later it died again this time the batteries were pretty much spent. I waited 5 min again started it up and proceeded about 10 feet. My prius was dead! so after walking about 1 1/4 miles each way to gas i finally put in the gallon i had gotten. 1 problem, the batteries were so dead the fuel pump wouldnt kick on, Rhut Rho..so i dug out the book and started to readit said turn the car to the off position and start......HUH? thats what i said. well anyway after about 5 min of messing around the engine started but was so weak it wouldnt go into drive. So i sat there watching the battery bars like a school kid waiting for the clock to tick once more to go home. finally i saw the battery bar click up another bar, and i yelled out YEE HA !!! and popped her into drive and slowly pulled away wondering what would happen. All the lights were off so i drove to the gas station filled up and drove home after that like nothing happened. Lesson learned? after the last bar beeps and starts flashing on the gas guage you have about 35 or 40 miles left (at 60 mph) then onece it shuts down you can drive slowly 25 mph or so for about 12 miles on the batteries. I hope this helps people in the future. good luck (by the way the whole ordeal took about 2 hours)...... Dean __________________
Congratulations! You almost completely drained the traction battery and reduced its life by an unknown amount. Here's Your Sign.
Simple answer: Don't do it. As Evan says, pull off the road at the first safe spot. You should consider running out of gas with the Prius the same way you would with any other car. It's not an electric car. Tom
Thanks Dean, I enjoyed your story -- that is exactly what I wanted to know. Can anyone more specifically explain what damage could occur or why damage would occur? Of course, we would not do this purposely, but it would be good to know the risks if ever faced with a decision to either proceed without gas or wait for help.
I've heard from an Expert Prius Technician about the horrors of running out of gas. Yes you might squeak by, but you could also put it into a condition where the car will not start without a technician service. That means having it towed to a shop. There is a diagnostic code which tells the tech that you ran it out of gas, so there is no point in lying. He says never let the guess gauge get down below 2 blips.
The main problem is you can drain the HV battery far below the levels it's designed to go. Normally SOC is maintained b/w 40-80% with a target of 60%. Extended driving on the battery alone can drain it much further...probably to around 25-30% SOC when it first shuts down, and the Japanese owners have seen as low as 18%. Deeply cycling the HV battery diminishes its life. I would also worry about the inverter potentially overheating with prolonged EV driving though I've never seen that reported. Consider, also, that all that time while you're driving along MG1 is spinning the ICE, the fuel pump is trying to pump fuel that isn't there and there are repeated attempts to start the fuel-less ICE. I can't think that's a good thing.
A typical phone battery lasts 2 or 3 years because we charge them to the top and discharge them to flat or almost flat. Most phone batteries need charging maybe 2 or 3 times a week. The batteries in a Prius aren't all that different to a phone battery but we put charge in and pull charge out lots of times each trip but because of the way the batteries are managed the batteries are expected to last the life of the car. If you drive on the battery without petrol you are using the battery like you use the battery in your phone, so if you drive on the battery outside the HSD managed state of charge you may only get a few hundred or so cycles like you do your phone battery. Just discharging once might be all it takes to shorten the battery life considerably. It could easily die withing the warranty period and as someone else said, if that happens you are on your own. Try searching "Battery dead" and "Cancelled warranty". http://priuschat.com/forums/prius-m...le-dealer-refusing-honor-hybrid-warranty.html
Actually those are quite different batteries with quite different failure modes. NiMH batteries, e.g. those in the Prius, are sensitive to deep cycling, and will lose capacity quickly if they are used that way. They can lose half of their capacity after a thousand deep cycles. (By the way, I don't believe that a single deep cycle, as is being discussed here, will cause a measurable loss in capacity. On the other hand, running the gas pump dry can't be a good thing.) The Li-ion batteries in your phone and laptop are not nearly as sensitive to deep cycles. They lose capacity much more slowly than NiMH. Taking a Li-ion battery all the way to zero can kill it, but they have internal circuitry nowadays that keeps that from happening. However that test was done over a short period of time. Li-ion batteries lose capacity over absolute calendar time no matter how they are used or even if they're not used at all! After a year or two, there is a noticeable loss in capacity. Beyond that, they often fail completely. The inexorable path to death begins as soon as they're manufactured. If you're buying Li-ion batteries, make sure they haven't been sitting on a shelf or hanging on a rack for a year. Fortunately for cell phones, folk tend to replace the phones after three or four years, or even more often, just to get the latest gadget. Laptops are similar. My laptop Li-ion batteries usually last about three years. If a car manufacturer guarantees a Li-ion battery for, say, eight years, then I would assert they have accounted for two complete battery replacements in the cost of the car.
just for some more info, When this happened to me the car had about 12-15k miles on it. It now has 80k with no signes of ill effects. And no, i have NEVER run it out again. ( i have driven about 50 miles after the last little gas bar beeped at me) ( i know pushing it a lil too far, I know, I KNOW !)
I was getting concerned there. Haven't had a running out of gas post in 2 days. Had to have a retroactive one posted.Thank you.
Oh, O.K.. I ran out of gas a couple of months ago. On the freeway. Drove for about 3 miles, at a reasonable pace, to the first gas station. It was very nice and quiet My passenger was impressed))
