Hello all,

I've done a few web searches looking for anyone driving from the Denver metro to Summit County or Vail with a hybrid. Found a few posts from Prius owners that said they ran out of battery 5 or 10 miles reaching the tunnel. Those posts claimed that maintaining 50mph was very difficult and passing was not possible.

Has anyone of you done the test with the 2008 Highlander? The dealership tells me that the battery pack is much larger so that shouldn't occure. I would really like to hear real life stories from you.

As I told the dealer, I'm not worries about driving in town or road trips on relatively flat terrain. I'm worries about those 30 to 40 mile uphill drives with 4 skiers, gear on top of the vehicule, defroster, heater and all the goodies going at the same time.

I hope a few of you will come back with positive experiences, I think this might answer our needs for a socially responsible AWD family car with a 3rd row of seats.

Thanks!

 

I would not worry with the Highlander Hy. Remember you have a 200HP 6 CYL gas engine as the primary power source. BTW - I have run mine down going over Hoosier pas from Breck and still have plenty of power.

I have heard the Ford Escape Hy has power problems when the battery gets low.

Andy

 

This summer, going the other way, I was out of battery for the trip from Frisco through the tunnel in my 07 Highlander.

We had stopped in Frisco for the night, and didn't have or take enough time to get recharchged before I got on the freeway.

The difference was that I couldn't run in the fast lane with the Porches and the turbo cars ( which I had been able to do all the way up to Frisco).

I was not crippled and stuck at 50 by any means. In general, since a large portion of your torque and horsepower come from the batteries, you are much more potent than the gas only folks at altitude.

Mark Mooney

 

Agreed on the high altitude power with battery. I expect it to be almost like a turbo because the lack of air isn't a problem for the electric engine. My worry is that at 10K feet, the naturally aspirated portion of the engine looses about 30% of it's power (3% per 1000 feet). So, if the battery is out and the 200hp is more like 140hp. Going uphill with the heavier 2008 might get pretty sluggish.

I talked to sales people in the Front Range and at this point, they are not willing to let me test drive it that far. They say they will "sign papers" saying I could return it if I'm not satisfied with the performance. Not sure I like the idea. I think that the Colorado law forces them to do that anyway if I'm not mistaking (3 days/ 250 miles).

Thanks for your input.

 

Do you have any references for this significant power loss with altitude in modern engines? I'm very skeptical. In my 2007 HiHy, I've driven from Denver to Grand Junction and back, passing through the Eisenhower tunnel, with no issues. I've also driven a similar route many times in my HCH II.

 

I'm a 2007 Prius owner and I took a road trip to Colorado and did a lot of driving around the state. I went through the Eisenhower tunnel and the 50MPH trouble isn't a very valid. The battery does die pretty fast going up the hills but once it does the gas engine just revs up really high to provide power. I still had enough power to go around overloaded pickups and other struggling vehicles; you just had to trust the computers to keep the RPMs in check. I also had the A/C on the whole time.

If you do a lot of mountain driving you'll really love the CVT found in most hybrids, in fact I wouldn't want to do driving like that without one. Going up the hill you run just as many RPMs as you need to provide the power you are asking. On the way down the hill drop it into the "B" (engine braking) mode and use the accelerator to get just the right level of RPMs to get the amount of engine braking that you need, all while not burning an ounce of fuel or touching your mechanical brakes.

 

I'm not positive, but I believe using the engine braking requires the ICE to be running and thus using fuel. With a hybrid, I believe you are better off leaving the car in drive and using your brakes, which with a light touch should utilize the motor/generators only and not your brake pads. Can someone else confirm if this is correct, and if it is, is there any danger of overheading the electric motors from continous braking use?

 

If you have a short downhill then yes, it is better to lightly use the brakes to charge the battery without wasting any kinetic energy spinning the ICE.

The "B" mode automatically uses the maximum regenerative braking force combined with spinning the ICE. At the top of the hill the engine RPMs are low but once the battery fills up, and it does so quickly going down a hill, the electric motors can no longer be used to provide braking force. At this point the engine revs very high to make up the additional braking force. I was under the impression that when providing engine braking the ICE is being spun but is not being provided with fuel.

 

Sorry it took so long to reply. I found various sources of information about the 3% power loss per 1000 feet. It seems to be a well known fact in aviation, that's why many planes use turbo engines. I personally felt the difference when driving non-turbo engines at high altitude before with modern engines (electronic injection is what I guess you are refereing to). If you are really interested in the details, I found this scientific article with formulas and all: http://books.google.com/books?id=DwU...MG3yA#PPA23,M1

 

You have provided me a 20 year old book about carburetors as a reference? Isn't that non-modern? My issue was with the 3% loss on modern engines. That is what I am very skeptical about and you did not address that at all.