New PiP Owners...More data please!!!

Yep. Sorry I was not clearer. 38% is max efficiency for the Prius ICE; I picked/guessed a bit lower number for the average.

 

You used MPG(e)

 

I don't see why the max efficiency of the would be part of the computation. The goal of the estimate was to related efficiencies, the energy was used. Scaling the actual energy used by an assumed efficiency presupposes an answer. I can see in my computation I did not account for conversion losses, but just using ICE efficiency is not sufficient either.

The issue underlying what makes this difficult is that that higher demand regions could NOT be satisfied by the EV mode. It is not sufficient to take ICE effective power, convert to kWh and say it what would be used. EV energy efficiency is non-linear with power demand so higher power regions are require more kWh/mile which would need to be accounted for.


Maybe here is a better way of estimating. On the EU test mild cycle R101 the Prius wen 23km in all electric mode. the Volt/Ampera when 83.

Trackyside's measurements of the prius charging is 3.28 kWh so since it goes 23km on the EU test it would yield 142w/km on that test. The Volt, using 12.9kWh to charge goes 83km for 155W/km. Taking the ratio, on a very standardized test which does require the ICE, the Prius goes 8.9% farther on the same charge.

 

Let me rephrase the problem: how much additional usable traction battery energy is required to replace 0.2 gallons of petrol burned by a Prius ICE ? The car load while using that energy does not matter here; it goes into the energy pot, and the final total distance is known.

Starting from 33.7 kwh/gallon, the upper bound is 33.7*.38 * 0.2 = 2.5612 kwh because that is the max efficiency of the the ICE. Now, I did amend my original post to try and account for conversion losses from the battery to the PSD since the 2.5612 kwh is energy at the driveshaft. Even the almighty Prius does not operate *all* the time at its max thermo efficiency, so I used 35%. I doubt I am off by much.

That was a 110V charger. How much more efficient is 220V ?

One other point to consider, charge amounts vary up to a couple percent between warm and cold weather. I thought Toyota published 3 Kwh full charge from the wall ?

 

I think my earlier analysis has an apples+oranges error, in using the 29 kwh wall charge amount, while the petrol energy equivalent was computed for the driveshaft. Here is a recalculation set so that all energy inputs are summed at the driveshaft:

Assumptions:
wall to battery is 85% efficient
battery to driveshaft is 85% efficient
average ICE efficiency is 35%

Data:
0.2 gallons of petrol, 29 kwh of electricity from the wall used to travel 100 miles on the EPA course

Calcs:
29 kwh * 0.85 * 0.85 = 20.95 kwh of wall electricity available to driveshaft
33.7 kwh * 0.35 *0.2 = 2.359 kwh of petrol energy available to driveshaft

Total energy at driveshaft to drive 100 miles = 2.359+20.95 = 23.309 kwh
Wall energy equivalent then is (23.309/20.95) * 29 = 32.265 kwh / 100 miles

Back to the Volt comparo, 36/32.265 = 1.1157 or about 11.6% further in a PiP.

Not too far off from AG's estimate, I'm surprised to say.

 

I believe trackyside was using the supplied 120v EVSE and measured with a kill-a-watt. My 12.9 was my volt supplied 120v EVSE (measured using a kill-a-watt). 240v should be a little more efficient for both but this is at least close to apples-to-apples.

Yep temps matter. When it was cold (10F outside, 40F in garage) I measured 13.1, but trackysides were recent measurements in mild weather so I used my measurements from early october about 60F.

Some toyota website someplace said, in Japanese, 3Kwh. But given the truncation of data in the PiP, its hard to say that means 3.0kWh.

 

Now let's see:
809 kWh from wall (your signature) @ .308 kWh/mile that's 2627 EV miles.
2740 miles (signature) minus 2627 equals 113 gas miles, and @ 6.7 gal (signature) gives 16.9 MPG on gas ???
2627 EV miles are 96%!! what an amazing result!

Something does not sum-up correctly in your stats! Maybe your average EV efficiency is about 325 Wh/mile rather than 308?

 

so in real costs on John's tank. he put in 8.5 gallons of gas @ $4 a gallon = $34 and 60 KWh @ .10 = $6 or about $40 which is about 5.8 cents per mile.

in a regular Prius we say 50 mpg for the same 685 miles would be 13.7 gals of gas or about $54.80 @ $4 a gallon.

so that is "currently" about $15 in saving per tank ful. gas is expected to peak about 20-30 cents higher than current prices

granted the numbers above can vary based on local prices and if you have solar, well then!

 

this is exactly the way i like to figure it dave, and to take it one step further, i like to convert the cost ($40.) into gallons (10) and divide into 685 miles for 68.5 mpg equivalent. but that changes based on your commute and plug in time. i'm hoping to achieve 100 mpge.

 

Yes, many different ways for guesstimating. My method came to a similar number, but I rounded knowing YMMV depending on conditions, so I just said 10% Its not going to be 0% and its not going to be 20%, and unless we make a test we won't know exactly where in the range that we are going to be.

 

I thought many users were measureing 3.15-3.2 kwh for a full charge. We don't even know if the Japanese SOC is the same.

 

that can be done easily if you have the charging infrastructure to support both home and away. i know a guy who has a Volt since Oct/Nov or so. still on his original tank of gas.

he charges up at home, drives about 17 miles to town to work, plugs in and then drives home at night. once a week or so, he will fire up the gas engine to run it for 10 minutes during a time he knows he wont be stopping (freeway, long county roads with minimal traffic controls, etc)

he is averaging around 300 mpg and that figure literally goes up daily.

havent seen him lately (i see his car plugged in FREQUENTLY) but he has been pretty happy with it

 

that's a beautiful thing! my commute is 7.3 each way and i can plug in at work.once a week i take my father to lunch 60 miles total so that will run the engine. other than that, it's an infrequent trip here and there so i think i should do pretty well. can't wait to start testing!

 

Here's my latest:







.

 

52 MPG (732mi/13.915 gallon) on gas miles and 270 Wh/mile (99.2kWh/368mi) on electric miles.

 

First 30 mile each way commute today... 1 mile or so to highway entrance, slight elevation changes for 5-6 miles, then BIG hill up 241 toll road and down, followed by 15 miles of pretty standard highway fare on CA-91, and 1 mile or so off-highway to work. I can charge at work. I tend to drive about 72mph up the hill, and 75mph or so the rest of the way.

In the PIP, it was pretty easy to EV it from home to the highway (used maybe 1.2-1.3 EV miles). I then left it in EV until the big hill and "let it blend", down to 6-7mi EV. HV up the hill, back to EV down, regenerated about 1 EV mile, and blended it almost all the way to the highway exit, but I hit HV to preserve 2.0 EV miles for the surface streets to work, which was probably about 0.5 miles too much.

On the way home, I blended all the way to the toll road and up the big hill (not best idea as I killed my EV miles down to about 1.0), but did not regen as much EV down as the slope is not as great. I blended as much as possible again, but had to HV for longer to save about 1.0 EV miles for the surface streets. Notable was for the first 15 miles (mostly "blending" at 72-75mph) was my consumption was 100 MPG, normally 48-50 in my Gen III.

Total consumption was 56 MPG to work and 71 MPG home, for 63.5 average.

For comparison, the same trip in my Gen III is ~40 MPG to work, ~50 home, for 45 MPG average (although this is really about 41-42 based on refueling numbers). I am interested to see upon refueling how close the PIP consumption meter is to real life. Even if the PIP is around 3 MPG "optimistic", it's about a 40% jump in economy without a huge difference in driving style.

The big thing for me to realize (as discussed elsewhere) was that using EV mode up the big hill was a huge EV mileage penalty without much benefit to instantaneous MPG (still hovered around 25 MPG on the instant meter, not much different than Gen III). Will not do that again. The other thing was that I was surprised how much more gliding and such I was able to do. In the Gen III I was usually just under 50 MPG "instant" at average highway speeds (light pedal pressure), where the PIP is usually just over, and not really using much EV mileage.

I still have much to learn, but impressive so far!

 

And composite 65.3 MPG(e) [1100/(13.915+(99.2/33.7))].

The 'EPA average' Volt driver is 60 MPG(e) composite.

 

I haven't been keeping a log, but here are my stats so far:

This tank:
307.7 miles
2 bars down on fuel gauge

HSI-1 307.7 mi. 124 mpg avg 25 mph
HSI-2 1296.6 mi. 74 mpg avg 33 mph

EV Ratio:
EV 21% 278 mi.
HV 79% 1018 mi.
58 kwh

(sorry, did not reset EV Ratio at last fillup)

Kill-a-watt acquired 2 days afters last fillup:

25.78 kwh
(EMC locally is 10.9 cents/kwh with taxes & fees)

have recharged 3 times dining out with about 4 EV miles remaining.

I'll advise, and reset, on next fillup.

 

John is doing 1/3 EV and 2/3 HV. Other owners are putting in more or less EV miles. I wonder what the average ratio is going to be.