What is your DTE after fill-up?

That's actually not fully accurate either. SOC between the start and end points can vary upto 20% with a depleted battery, which is about 7 miles, and that would be an error of 1% or more, depending on the miles driven. Of course, the driven miles shown on the odometer can also be 2% off. You may want to look at the battery icon on the MFD with a magnifying glass to have the initial and final values match.

 

As I said the error can be 1% or more, as the HV SOC can wildly vary.

There is also the possibility Prius Prime doesn't get as good an HV fuel economy with a depleted battery when it runs like a regular Prius because there is less flexibility on the EV driving. Obviously if you restricted the EV-driving scenarios, you would reduce the HV fuel economy. I don't know if the computer relaxes the EV-driving scenarios with the SOC, say, above 5% as opposed to fully depleted.

 

It does matter. I estimate a 1% error in the HV fuel economy on a full tank unless you deliberately match the actual initial and final SOC on the graphical battery icon on the MFD. In the extreme case, you can drive several EV miles in the HV mode with a fully depleted battery ("--" reading) before the ICE kicks in, giving you a 999.9 (∞) mpg HV fuel economy.

 

Yes, however,

"--" ≠ 0% SOC.

"--" ≈ −10–+10% SOC.

 

So, (assuming those percentages are accurate) to use round numbers, 10% either way on SOC would be roughly three miles either way. Spreading that out over a full tank of, say, 550 miles is about half a percent.

The surest way (least unsure) to know HV mpg is to start with a full tank and always put it in HV when driving and do that for a half tank or more and then fill it again. Anything else makes too many assumptions and even this way assumes the two fill ups ended with the same amount of fuel in the tank. The more miles on the tank, the more you dilute that potential error in fill volume. Still, this is plenty accurate as long as there's not an Olympic gold medal at stake.

 

I was driving with low pressure (about 33 psi for most tires with one being 29) for hundreds of miles. Filled them to 38.5 and went to gas station. Apparently I was still running 50 mpg.

DTE 570 mi.

Posted via the PriusChat mobile app.

 

I finally bought gas again. Sheesh! It's gone up over 25% since August!

Latest DTE is 564 which is another new record since I started tracking it in October, 2019.

I actually went, 3,553 miles on that tank and it took 8.71 gallons to fill it. I suppose I could have gone a lot longer, but just felt like it was time to freshen it up a bit. Also, I've got a 60-mile drive coming up next week and don't like doing that when the gauge is down to 1/8.

Cost per mile including electricity was a bit higher than last time due to much higher gas price even though I went farther on one gallon less gas. Total cost of gas & electricity was $69.09 which is just under 2 cents/mile. Last tank was just under 1.7 cents/mile.

 

My third fill (second after dealer's fill) was 615 miles. I expect the fourth fill to be even higher. I guess I am a hypermiler.

 

I tend that way a bit. But the traffic engineers here went to a special school where they learned to set speed limits and traffic lights so that most people spend most of their time either braking or accelerating. It's infuriating.

 

I'm down to 1/3 tank now after filling up in 2019. Thats progress I guess. Was $2.059 way back then. Sadly, 2020 saw only 1,850 miles driven, because... COVID. I've got 2,150 miles on that tank so far, obviously almost all of it electric. And my 12v battery is almost dead.

 

I visited a gas station for the first time in about a month, which has been a lot nicer than weekly visits when the Tacoma was my daily commuter.
The gas gauge was somewhere around 1/16 tank remaining when the fuel light turned on. Since this was my first time playing the DTE game I didn’t want to chance it and filled up a few miles after the light turned on.
The Prime took 9.13 gallons and reported 508 miles DTE. So 55.6 mpg for 95% freeway speed driving (I run it in EV mode getting to and from the freeway, on downhill slopes in the freeway, and in stop and go freeway traffic). Next time I’ll push the limit a bit further now that I know there was plenty of fuel still in the tank.

 

Sorry.. Wrong window..

 

I finally filled it the other day. 15 months on a tank. Even then, it only took 7 gallons. Reported 560 miles post fill up. I immediately used a few gallons for the COVID vaccination second dose trip 3 counties away.

 

DTE for my fourth fill is 647 miles. Is this considered any good? My third fill was 615 miles. 700 miles still seems far away.

 

No, not good. GREAT!!!!