Thanks Soopahman for your comments ...

The battery only mode and the usage of battery is a little clearer in my mind now ..

One interesting observation was when I filled up my Prius tank yesterday evening and drove home (knowing that the driving was done for the day .. I used the battery-only mode towards the end of the drive). I recorded a record 92.2 MPG for the 2.1 mile ride!

This morning, I did not get the ride with the car-pool that I usually do with someone else .. so my wife dropped me at work today .. well, it was I who drove from home to work .. and I recorded an overall 64 MPG for the 21 miles ride this morning ... my wife continued on her journey towards her university after that .. I wonder what number I would see in the car in the evening

 

My bet is still to avoid using battery power.
http://hybridcars.about.com/od/owner...seandglide.htm

Prius uses about 1.0 to 1.2 ampere HV battery current for "basal metabolism".
Also, it uses 2 to 4 amps while no arrow gliding.

Ken@Japan

 

We found we'll see worse overall mileage when we finished driving at low battery level.

Ken@Japan

 

Indeed, I'm trying to just sum up some quick examples.

I live at the top of a hill, at the bottom of which I've got 7 bars every morning. I'm going to be finishing trips home in electric-only now to use up the battery that's gonna get filled anyway. Constant 5mph with the gas engine running is a mpg killer.

 

With my NHW11, EV is dependent upon having enough SOC and slow speeds. So in the morning, I keep my initial speeds to ~25 mph until the coolant light goes out by driving through my neighborhood and then moderate speeds, 38 mph, as much as possible on the way to work. There is one short section, ~2 miles, at 55 mph but the rest is 38 mph and below. The last mile to work, I go back to 25-30 mph to let EV mode boost my mileage.

So my profile is: (1) slow for first 1-2 miles to minimize warm-up fuel burn, (2) moderate to high speeds for 6-7 miles, and (3) slow at end, 1+ miles, to use EV into parking space. In cold weather without my thermistor hack, I extend the first phase, morning warm-up drive. I've also found re-warming by going out to lunch helps the evening commute.

Bob Wilson

 

It is in your special case.
I explained in general case.

Ken@Japan

 

When you perform the test, perhaps you can track the results in the mileage database?

Bob Wilson

 

I dont live on top of the hill, and I seem to be getting better MPG when I bleed off the battery when I am done with driving at the end of the day, by doing the last quarter to half a mile in battery-only mode.

When the ICE comes on as soon as you start moving in the car the next morning, the ICE starts consuming fuel, but you are ready with a thirsty battery, which then starts gulping down those AMPs ..

If the battery's SOC is already moderate (as Prius' on-board computer tries to maintain in general), then the ICE fills up the battery to higher levels .. which might not be the worst thing in the world, but then, Prius will cut the ICE off later in order to use that extra charge in the battery (extra meaning more than the 6 bars), and so we see the conversion losses. On the flip side, if the bars were say 4 to start with, while the ICE is on, you move your vehicle and the batteries get slowly charged up to 6 levels, and now, you've warmed up the Prius and are ready to take on the hypermiling world! Right?

Just my 2 cents .. I do not consider myself as any level better than novice still .. Am learning from experts like yourselves!

Cheers!

 

BTW, you' all might want to send Ken a private message asking about his super scanner. It works with the NHW20 and I haven't seen much posted here recently.

Ken, would you mind starting a new thread with some photos and technical stuff about it? I suspect by now you' all have made some improvements that I'm probably not aware of.

Thanks,
Bob Wilson

 

Definitely. Anything special I should take note of? I'll mention the mod and new strategy in the notes for the first tank that uses it (so, this tank).