Lost all Power going up mountain passes

<div class='quotetop'>QUOTE(Per @ Jul 31 2007, 09:37 PM) [snapback]488451[/snapback]</div>

That was my thought going up Monarch Pass a few weeks ago. The pedal was floored and i could only get it up to 42 mph. Once the battery is in low range does the engine use some of its juice to keep the battery charged, diminishing the HP used to make the car go?

Like someone else said, momentum is the key. You will loose a little speed as the grade gets steep; but trying to regain speed once you have to slow down for an 18 wheeler is almost impossible.

In the end, its worth it....Once over the pass the engine will not cut on for a long time.

 

The thing to remember is that this is no hill, this is a mountain. Elevation is 11,000 feet at Eisenhower tunnel.

I have noticed the car does better in cooler weather (more oxygen, less A/C) and it does better the faster you go. Once you get over the first big climb, it can regen on the first descent, then if you hit the start of the next climb at about 80 mph, it seems to go up with no problem.

Again, there could still be something wrong with my car, though. See thread on battery replacement.

Nate

 

One more data point for you. My daily commute takes me over two 9000+ ft. passes. The climb up one pass increases 1500 ft in the last 3.5 miles. When I start up this section my battery is usually already down to one bar. Most of the road is too windy to drive over 35 mph, but there is a straight section about half way up. So when I got to this section this afternoon, I floored the accelerator. My Prius got up to 51 mph, but would got no faster.

This was at about 8000 ft, the AC was off, windows closed, outside temp about 75F, and tires at 40/38. Also 180 lbs of people and junk in the car.

 

Hi Wileec,

Another PC member reports a wierd thing while driving up a mountain during a vacation trip. She turned the AC Recirculation off, and got allot more power. AC temperature setting was unchanged. I responded that it might have been due to high humidity in the car (she had one or two passengers, and had been driving windows closed and AC on for some time before the mountain) and the automatic climate control might have been trying to dry out the air.

Somthing for you to try.

Also, I was asking for you to try to find your steady state maximum speed up-hill. That is, no battery consumption by the drive train at all (yellow arrows on the MFD). In the steady state situation, the battery will not go down hardly at all. That will be the speed you can continue almost forever up a hill of that grade and altitude at. You said 35 mph on a steep canyon road, and it was discharging the battery. So, does this actually mean something like 26 mph is as fast as you can go without the battery? As the battery has about 1/3 the HP of the engine, thats what it works out too, assuming all load is elevation change related.

Accellerate quickly, then slowly slow down till the yellow arrows go off. Then try to hold the accellerator at this level and see if the yellow arrows come back on or not. If they do, then pull back a little more. Repeat until you have no yellow arrows going to the battery.

 

Both of our hybrids have done I.15 over the Contenental Divide, multiple times, 70mph. NO issue.

 

<div class='quotetop'>QUOTE(hill @ Aug 3 2007, 09:00 PM) [snapback]490326[/snapback]</div>

Where does I-15 cross the Continental Divide?

 

<div class='quotetop'>QUOTE(RedRockPrius @ Aug 4 2007, 10:06 AM) [snapback]490525[/snapback]</div>

Just north of Butte Montana. It's a pretty good pass, but not nearly as high as the Colorado ones. Steep hills but with air. Then again at the Montana/Idaho boarder. Not so dramatic there. Pretty much flat, well, a little hilly.

 

<div class='quotetop'>QUOTE(David Beale @ Aug 4 2007, 12:49 PM) [snapback]490539[/snapback]</div>

That's a little narrow ... and Butte is slightly on the Eastern Side of the Divide. The divide actually follows the Idaho / Montana border up to Missoula, where it veers east, before heading back into Canada.
Example:

[attachmentid=10391]

Yes, Colorado gets steeper in some places, but it's the winters in both that equall things out. That's when you find yourself in BOTH locations, slowing down to 20mph following a truck it its tire trenches, to compensate for those white-outs. Whoo!

 

On July 5-6, we went from the BayArea to Mono Lake & back (545 miles). Went over Tioga Pass - California's highest - over 9900 feet! Drove normal - had a lot of time. NEVER noticed any unusual slowing! At Mono Lake we went north & recrossed the Sierra Nevadas at Sonora Pass - about 9800 feet. Averaged 47 MPG. Had 6 (six) solid bars on the downgrade! ;~)

 

I noticed that while driving carefully at 20-25mph up twisty steep 1:6 roads that the screen shows the electric motor supplying energy as well as the ICE and depleting the battery. It was down to 2 bars at the end, then normal roads /speeds and the ICE charged the battery. If the journey had been twice length I'm not sure what would happen.

Is there an issue with gearing at these speeds that power has to come from the ICE and the motors ?

 

<div class='quotetop'>QUOTE(prius2go @ Aug 16 2007, 11:07 AM) [snapback]496763[/snapback]</div>

Nope, there are no issues with the possible gearing ratios between the ICE and the wheels, it's just the hybrid system that tries to keep the ICE at effective RPMs and thus supplying battery power to assist the ICE.

The way I see it the Prius, just considering the ICE, is a badly underpowered vehicle. Therefore you have the hybrid system, with the extra 50Kw electric motor that hides the shortcomings of the ICE. The ICE is enough to maintain normal speed, but it needs help during acceleration and hillclimbing. That is why people sometimes have problems with keeping their speed up loooong hill climbs. The assistance from the electrical motor hides compensates for the little ICE, while that little ICE is why the Prius is so fuel efficient.


Stein

 

I just got back from a 1500-mile trip to and from Santa Fe from St. George, UT with some local driving in the Santa Fe area. While in Santa Fe, I used my Prius to transport myself, my son and his wife (total weight around 550 pounds) to the top of Sandia Crest (elevation almost 11,000 feet above sea level). We also took a drive in the mountains northeast of Santa Fe. At no time, including the long climb to the top of Sandia Crest, was there any evidence of sluggish performance. The AC was operated in Auto mode all the time. The descent from Sandia Crest made good use of "B" mode.

I've also done a fair amount of driving in the mountains of southwest Utah, usually alone, with no noticeable sluggishness under any conditions.

 

Sounds like you have a problem. I cannot consider diagnosing what it could be, but the only time I have had a problem similar was with poor gas from a station with too much ethanol. I have traversed the U.S. twice and had absolutely no problems with the mountains. We also did several weeks in Colorado last October. It sometimes does cause the engine to wind up considerably but certainly keeps up with other traffic and easily passes those going slower.
A friend had a problem after backing down a driveway with his Parking Brake on which adjusted the rear brake too tight, not enough to make smoke but enough to cause much drag. Another friend noticed the rear wheels and drums were very hot after their commute.

Good luck with diagnosing the problem.