Prius Prime Plus in my hands

You didn't pay for it up front?

 

I did.

Think of it this way:
What is the difference between me taking out a loan at 4% apr, or using my money and losing out on savings at a 4% apr ?
What is the real cost of a loan at 4% apr if inflation is 4% and my wages keep pace with inflation ?

 

The difference is, no bank would exist if that were reality.

The spread (the real spread, which is far from zero) is what you paid, whether you think you did or not.

 

Perhaps, but that is a matter of timing. Just look at current home mortgages and historical inflations rates for obvious examples where you are wrong.

In this case though, the inflation is built into the avoided future utility cost increases. The construct is the point I'm trying to show you so that you realize that time-money value has not been ignored.

 

You are still making an invalid comparison. This has nothing to do with inflation.

It's the difference between walking into a bank and asking for a loan, and paying, say, 5%, and giving them cash and asking for interest for which you'll receive about 1/2%. That's the spread.

 

<<shrug>>

Have it your way, but stick with your day job.

 

One of the things I do in my "day job" is calculate levelized cost of energy for wind energy installations.

Look at page 2 here:

http://www.nrel.gov/docs/fy16osti/64281.pdf

See "FCR"? You set it to zero in your model of cost.

I wish it were so. It's not.

 

i suppose it helps to be awake all night.

 

The engineer said 1/3 of a gallon.

Assuming the usable battery energy is 5.7kWh and the thermal efficiency of the engine is 40%:

(5.7*80%)/0.4 = 11.4kWh gasoline

11.4kWh/33.7kWh/gallon = 0.34 gallons.

That doesn't include charging losses, but it seems pretty consistent.

 

Probably very close, but we'll never know for sure without Bob (the engineer) who is willing to procure for us real world, directly measured data. He's kinda the MythBuster of Priusdom (without the explosions).

 

Likely, he just does not admit to the explosions.

 

Something is off here, unless you think that forced charging followed by EV mode is more efficient than HV mode.

1/3rd of a gallon in HV mode is 18 miles of range
80% of full EV range is 20 miles



Looked at from the ICE downward,
A gallon is 33.7 kWh
1/3rd is 11.2 Kwh
I doubt the Prius ICE will be in it's best power band during forced charging, but
in the range of 35 - 40% efficiency, 3.92 -- 4.48 kWh of mechanical energy will enter the generator
80% of a full charge is 0.8*5.6 = 4.48 kWh

My WAG is about 14.5 EV miles from 1/3rd gallon forced charging. There is a very good reason why the Prius is not a simple serial hybrid.

 

Uh-oh! Morphed from Engineer to an Engineering Pyromaniac!

 

Dupe

 

This can be true in certain circumstances, and maybe more than we think of.

In cases where charge mode drive brings the ICE to a higher thermal efficiency than the efficiency of pure HV in same conditions. The higher efficiency works for charging as well as for propelling the car. This means that an HV drive for the same conditions cannot accurately be a blank test for the charge mode test as it is done at different efficiency.
Volume of gasoline used for charging in charge mode may not easily be accurately found, and if you ask me, it is not that important to know. More important IMO is to find out the circumstances in which there is a net gain in using CM.
If I owned a Prime I would test it this way:
On my regular non-short trip, after driving HV so Ice is warm I would reset meter, switch to CM for charging empty-to-full (software full) at constant speed, registering CM mpg, continue driving EV mode at same speed to back to HV, registering miles driven.
From above, an equivalent HV mode mpg can be calculated, sample calculation I gave in this post
This equivalent mpg can be compared to actual HV drive mpg of the same road at same speed and conditions.
Test may be repeated at other speed.

 

Nice work -- thanks!

A lot worse than I guessed, but I'd like to see more than 16% SoC accumulated if you have the opportunity. I don't think of SoC as being very linear.