That's 13 mpg less with the AC on. Mine varies from 2 to maybe 5 mpg less with the AC. I bet the day you tested it was humid and very hot. That defiantly pulls on the AC and mpg. AC's don't seem to be very happy when the humidity is high.

I'm liking your 80 mpg. I can ask my wife again about the Enginer system around Christmas.

 

Jimmy,

You guessed it. On the "with A/C" case it was very hot and so humid that you could drown on a deep breath. A day or so later a front came through and sent the temperature and humidity down to quite comfortable levels for the test without A/C.

Humidity increases the A/C cost in several ways.

First, high humidity decreases comfort. High humidity interferes with your body's ability to cool itself by evaporation of perspiration. With low humidity I might be comfortable with the car's auto temp setting near 80, but with high humidity and high outside temps, I need it at 72- or even lower - making the A/C system work a lot harder.

Second, it takes more refrigeration energy to remove humidity. The air conditioning engineers refer to "sensible heat" (the amount of energy removed just to lower the air temperature) and "latent heat" (the amount of energy associated with the condensation of the water) The higher the humidity, the more A/C load due to the latent heat.......... DOUBLE WHAMMY !

Third, the higher the temperature, the more water vapor the air can hold .......TRIPLE WHAMMY !

But there's also another reason for the huge A/C penalty on this trip. The average speed was probably only 15 or 20 mph. The A/C in this car is electric. All other things being equal, the A/C will consume a fixed amount of energy per unit of time - not distance ! So, the amount of energy consumed per mile would be inversely proportional to vehicle speed.

For a given heat load and A/C demand, then, if I would see a given mpg impact at 60 mph, I might expect twice as much impact at 30 mph and four times as much at 15 mph.

This expectation has been pretty much borne out in my experience.

The plug-in savings are truly remarkable on this trip - even more so with A/C in use. But I would not get too crazy at this point in extrapolating to a general expectation. Other experiences I've noted here show a much more modest benefit, and it's going to take a significant observation period to see how it all averages out.

Jack

 

By the way, Hyundai will come out with a Sonata hybrid sometime late this year.

Some reports have it capable of travelling up to 60 MPH in electric-only mode.

This could be a real game-changer for Toyota.

Joe

 

The Ford Fusion can run up to 49 mph in the EV mode. After a closer look it don't stay in the EV mode very long at a time. It's mpg is maybe 1 mpg higher then the TCH.

I'm sure we will see more Hybrids and All-Electrics coming out by the end of the year.

 

Here are some navigation screen shots from my very first test drive with the Enginer plug-in conversion.

They are all from a 17 mile test of the 2 KWH system. The test was done with out air conditioning in mild weather (70;s) in slow, level, driving with several stoplights in light traffic following a very strictly enforced 35 mph speed limit, using as much hyper-miling technique as traffic would allow. The test involved several round trips and ended at the initial starting point.

The first shot is from the first two miles of the test.



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http://img203.imageshack.us/f/screenshot829mpg.jpg/

The second shot is from approximately 5 miles to 11 miles.



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The third shot is from the final approximately 6 miles.



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http://img806.imageshack.us/i/screenshot685mpg.jpg/

Overall mileage for the entire 17 miles was 71 mpg.

You can see from the bars that I was holding EV mode about 75% of the time. Without the stoplights and traffic, I may have been able to do better.

At between 16 and 17 miles, the charge on the 2 KWH auxiliary battery pack had been depleted. (Now that I have 4 KWH, I presume that I could get a 32-mile range under these same conditions, and I have seen a 41 mile range in highway driving.)

You can also see from the mpg indications that the perfromance was best at the beginning of the test and worst on the final leg when the auxiliary charge was dwindling.

 

Jack,

You may have found the automotive version of the "fountain of youth." I'm surprised there hasn't been more media attention of the Enginer system, or more interest from Toyota in making this battery pack part of the standard Camry hybrid, or at least some sort of "Super Camry Hybrid" option package from the factory.

Based upon your results, is it safe to assume that a larger battery pack would extend the range even further vs. increasing actual mileage?

Joe

 

Yes, at last the primary benefit would be the increased range.

But since the system seems to work best when the charge is highest, there may well be some additional mpg boost benefit as well, but I think that it would be a second order effect.

 

So, a loaded Camry hybrid is about $34K. And, some dealers are discouting the 2010s up to $6,000. Add the $3500 for the battery pack and is is up to just under $38K minus whatever discount you can negotiate.

That seems like a better choice than the ever-promised Chevy Volt, which is rumored to be $40K and will almost certainly be in short supply and heavily marked up by the Chevy dealers that get one--whenever that comes to pass. Translated, the Volt will probably be about $45K to the first few thousand buyers.

Toyota proven reliability vs. Government Motor's first effort at an electric car (that you can own) for less money than the GM 'experiment'? Noooooo brainer!

 

I keep thinking of Jack's extra batteries holding a charge for such a long time. This enables him to have battery assist from every red-light, and while the ice is running to up the gas mileage even higher.

I picked up a full mpg from 55 to 56 on this evenings round trip to town and back. I ran the AC on the way to town due to the 94 deg heat. No AC on the way home as it had cooled off. I give this over 5+ mpg increase to these michelin saver tires from last summer.

By the way the humidity at 5 pm when we went to town was 5% and may be why the AC did not pull the mpg down very much.

Is no telling what kind of big numbers I would get with one these enginer systems. Jack, I got the wife thinking on it again. We make mutual decisions so maybe in time.

It may be the 2012 TCH that will be the redesign and may come with lithium batteries. I think the 2011 looks more like our cars except for a smaller grill opening. I don't think their is much info on it yet. I bet it comes with a similar NiMh pack like Toyota has used in the past.

 

The savings is only determined by how often you recharge the system. 1 charge per tank will only net you 10 extra miles per tank at 35 mpg normal and 50 mpg for 25 miles(or .5 gal used) this is on equal fills of 15 gals per tank. If you recharge constantly averaging the 50 mpg, you would save 51.15 per month or 613.80 per year based on 2000 miles per month(which my wife does easily with 3 teens). .
The system would pay for itself in 3.26 yrs. For the 2 kwt system. The 4 kwt system would take 5.7 years to break even but would require less recharges.. you have to take into account 4 hrs charging time for every 25 miles driven in this equation, which could be a stretch of the overall savings.