Learning about my prius

The gas gauge is not a "straight line" gas gauge, meaning the amount of fuel for each bar is inconsistent. Add to that fact the rubber bladder holding the fuel in the tank is of varying flexibility at almost each tankful. Many of the long time members here have it down for their respective cars and are probably close to ours but it's not exact.

I just posted some results related to this issue for newer Gen II owners in this thread:

Fuel Bladder Capacity and the Weather | PriusChat

There are quite a few other threads about it as well.

Welcome to the club! These are great cars.

 

It's hard to say exactly how much fuel is left in the tank when the light starts to blink. I've heard of some running out of gas at 1 Pip before it started blinking and others driving a hundred miles. I don't think it's entirely predictable.

The Prius doesn't really have a "tank", it's more of a bladder. See this thread to see how one member opened one up to see what's inside: the gas bladder: exposed! | PriusChat

For this reason, the fill amount varies every tank. I track my fuel economy and If my fill numbers for each tank were to be believed my numbers would look something like 45mpg, 65mpg, 45mpg, 65mpg, etc. However averaging over several tanks, I'm doing about 54mpg. This is because there's a an almost gallon variation on each fill between how high I can fill it. This is very frustrating for those attempting to track their fuel economy, but if you average several tanks together you get to know your real number.

I think to be safe, one should treat the tank like it has 10 gallons of usable capacity. Even in cars with normal tanks, getting that last gallon or half gallon in usually requires spending half an hour slowly filling the last top of the tank. The Prius is even more of a challenge. When you filled 9.3 gallons, you might have had less than a gallon left in the tank.

Personally, if I'm in town I fill up as soon as I drop to 2 bars. If I'm traveling between towns I fill up at 3 bars. I don't mind putting 8 gallons in every 400-450 miles. It's still significantly farther than I could travel with my last car on a tank.

Also keep in mind the Prius can offer more challenges than other cars when it runs out of gas. It will usually throw codes which have to be cleared to restart the car. Just filling it with gas usually doesn't clear the problem.

 

No. No one does. Your tank has a flexible bladder in it which holds the gas. How flexible it was when you filled the tank determines how full you got it. How flexible it is as you empty the tank determines how much of the gas you can get out.

I have run dry with in 7 miles of the blinking light, I have driven 50 miles and not run dry.*

Over the years I devised this advice:

If your Mother in Law is in the car, get gas at three bars. Nothing would be worth hearing from her the rest of her life about how you stranded her.

If your spouse is in the car, get gas at two bars. You will never live it down, so lets not go there.

If you are solo and do not mind the walk with at least 3 gallons of gas, you can get gas at one bar.

If the last bar starts blinking, get gas NOW!

* the car refuses to go faster than 35 and the dash lights up. Quit driving NOW! if you run the big battery down, no one local has a charger for it, including your Toyota dealer. Expect at least a week before they can get one. IF you try to start it 3 times while out of fuel, it will set a code and need to tow to dealer. It will take 3 gallons before it 'sees' you added gas.

May all your walks be for recreation!