Jack,

I remember you saying you saved 25% gas on the round trip to the airport. That to me would look more like this for near and in city driving.

orig mpg.....with enginer pack

30..............37.5

35..............43.75

40..............50

45..............56.25

50..............62.5

 

I'd better clarify a little.

On long highway trips, this kind of system will be of practically no use.
Once over 40 miles, the aux pack charge will be gone, not to be restored until plugged in again.

The trip to the airport and back is mostly interstate driving at over 60 mph. That's what I refer to as high speed highway driving in this discussion. I've recently also made two other similar round trips of nearly 40 miles and mostly 60+ mph interstate driving. All of these trips result in approximately 50 mpg with heavy A/C. Without the plug-in unit, I would have done approx 40 mpg on these trips, possibly a little better. (In the winter, I'd probably do 45 mpg.) The 50 mpg vs 40 mpg is what I'm intending to call a 20% reduction in gas consumption, or equivalently a 25% increase in mpg. So far, my experiences with this type of trip have been pretty consistent.

What I'm generally referring to as city driving in this discussion is typically under 40 mph, often a good bit slower, often stop-and-go and sometimes involving trips either plenty long enough or entirely too short to average out the start-up penalty. My experiences so far on this type of trip have generally been a doubling of mpg, from 50 mpg on trips that were previously under 25 mpg (nothing showing on the MFD 25-to-40 display) all the way up to 70 or 80 mpg on trips that previously gave 35 or 40 mpg.

 

I wanted to add the percentage to the base mpg to see approximately the mpg improvement the pack would make.

I did the same thing adding the 8% improvement the michelin energy saver a/s tires were suppose to give. Once the tires I purchased were broke in, I was getting 6% to 8% increase. If I drive slower I can get a 10% increase over my same driving a year earlier.

I do run 42psi cold using nitrogen in the Saver tires. I ran 42 psi (air) in the oem Energy tires that came with the TCH.

 

Jimmy,

I see.

For completeness, I should add that for quite some time I have been running about 42 psi air in my original Michelin Energy's, and that I regularly use a block heater, summer and winter, to reduce warm-up penalty.

No matter how high is the best city mpg you can now get with your nitrogen and Savers, I'd bet you could roughly double it with the plug-in unit, as long as you keep under 42 mpg.

Jack

 

I have always got into the 50 mpg range a few months after learning how to drive my then new TCH. Mainly learning that the EV efficiency helps best around 40 mph.

Jack, I hit 60.8 (tank) on Oct 24, 2009 after I broke in the new Saver a/s tires I put on my car. I drove 40 mph to down and 38 when in town w/o the AC. Temps at the time were 75 degrees. This was up in the day so their was little traffic on the Alamogordo/El Paso highway. It's also very level around here and I use the cruise control all the time, even in town.

Sept 25, 2009 I had made similar runs to town and back during the day. The round trip is about 33 miles. This time the mfd reading was 63.6 mpg for the tank. The only difference was the temperature was at 85 degrees and I had added 5 ounces of Lucas upper cylinder lubricant.

The car gets good mpg due to our 4200 foot elevation and very dry humidity. Toyota mentions not using any additives as it might damage the oxygen sensors. So I decided to not add them and have been using Phillips 66 gas. Chevron was my other choice out here but I can't tell any difference between them.

I try to stay with the same multiple pump station that seems to do lots of business. I figure the gas is fresher and runs good or they would not be doing such a good business.

I been running the AC to town but not on the way back as it's usually after dark. The mfd is sitting on 55 mpg and the tank is almost to the low fuel light level. I may fill up this evening. This is amazing getting into the mid 50's over and over with the AC part time on. I did good to get in the low 50's with the oem Energy tires. I can tell the Saver tires are helping out..

 

I talked to my wife about getting the extra battery pack. She rather wait and have a look at the new Toyota Hybrid's first. Not sure when they may come out, perhaps February March of 2011.

 

Jimmy,

64 mpg is pretty darned good.

Don't know how big a bet I'd place on doubling that, even under 40 mph, but I'd say it would be for sure that you'd beat my best so far of 83, and I would think that 100+ would be within your reach.

Don't know whether you have the navigation screen display, but if you do, an instructive thing would look at the screen for a 30-min stretch of one of your 60+ mpg trips and note what % of the bars are at 60. On my 70 to 80 mpg trips, I see about 75% of the bars at 60. Previously I saw less than half.

I inferred that the aux batteries allow the thing to stay in EV mode a larger percentage of the time, probably by way of keeping the SOC higher, longer.

I pray that I don't get the new car bug any time soon, but if I do, I suppose that I will get something into which I can transplant the plug-in unit.

In fact, part of me was hoping to get some level of inoculation against the new car bug by acquiring the plug-in unit, but I confess that the thought of new Prius or Lexus 250h with the EV mode switch combined with the plug-in unit is starting to tempt me.

Jack

 

No I don't have the navigation in my TCH. I used the mfd battery with the + and - on the display. I'm learning to shut off the EV once the battery gets about 10% below the + sign. The generator don't seem to pull on the engine as much as when the battery is down to 40%.

You bet I would sure put those lithium's to good use. I bet I could make it the 8 miles to town and still have enough EV left for half any city driving.

I am a little jealous. My wife bought a 2010 Ford Ranger pickup a few months back. It's a 4-cyl, automatic and she is already getting 27.5 mpg and lately 26.5 with AC. I predict 30 mpg once it's broke in.

She got 24/25 out of the '99 with the heavy V-6. This new aluminum 4-cyl has the same horsepower, improved automatic transmission and a lighter truck body. I would think the car manufactures are all headed this same way to improve on the gas mileage.

 

How's that ?????

 

I'm learning to shut off the EV mode (42 mph and slower) by driving at 43/44 mph. I have had good luck by not allowing the EV to drop the battery below 60%. That could be 65% as this small display battery indicator don't actually show percentage. I do know the average max charge is 80% which would be even with the + sign. Lately I have allowed the EV to take the charge down to about a 1/8" below the bottom of the + sign. That would be in the 60% range.

I would drive in the EV mode on the level highway coming home at 40 mph at night. I would let it go down to - sign (minimum charge) or 40% and the engine would start to charge the battery.

During this heavy charging time I started noticing I'm only getting 45 mpg at 45 mph (I use this speed to charge and drive with the ice) The charge after a mile or so will not go to 60 mpg again till the charge reached to about 60% on the battery indicator.

I figured to stay away from the low battery charge which seems to pull down the mpg. Better to allow it to work between 60% and 80% on the traction battery.

Jack, my EV speeds are 38 city, 40 highway only if low traffic, other wise it's 45 mph so any traffic can pass. This is a 4-lane highway we drive on. It's a 8 mile trip to town. Most of that is a 55 speed limit.

I drive 45 anytime the ice is running. I know all the EV areas around town and coming home on the highway. I took me a couple years to learn all the spots in town and on the highway were I could squeeze out a few more tenths per gallon even with the AC during the day when the temp is over 90 degrees.

I need to mention - when the battery is charged up to full or 80% then the electric motor will kick in more often to aid the ice. I think it's called the Stealth mode it both the elec motor and ice run at the same time.

I moved up from 55.0 to 55.4 mpg on this evenings trip to town. Last year the AC most times would pull down my mpg. I feel it's after I put on these Energy Saver a/s tires that making the difference. The low fuel light came on tonight so I got to fill up tomorrow.