2009 Prius - Trouble in mountain driving?

When your battery runs out you are running on 74hp for a 2900lbs car. That is not the end of the world but the engine is going to have to work hard. It will not overheat or damage the car unless your car has something wrong with it. You will be able to maintain the speed limit!

Think of all the Microbuses (t2) that have gone up that hill with from as little as 42hp to 70hp and usually just a tiny bit more weight and far worse aerodynamics.

 

"All season" tires aren't. The compound is too hard at icy temperatures, so good grip on ice needs winter tires. May not be worth it in TN, but they're nice to have here.... not that everyone here swaps seasonally.

 

Oh, c'mon. I just took mine up Washington and down a couple
of weeks ago, and I've done the Kanc a couple of times. No
issues, and if traffic accomodates it you do a *lot* better
MPG-wise by keeping your revs under 3000 on the climbs. The
big hulkin' RVs you're mixing it up with will understand.
.
For the comparison test, I would suggest doing multiple runs
and ignoring the "energy" screen. Try to start with a consistent
SOC from a given startpoint, i.e. pull over somewhere just before
the 7-mile hill and force-charge until you, say, *just* go to
seven green bars, and then start up. Do that on both cars and
take at least an average-of-three set of observations on each.
.
_H*

 

Hobbit,

Thanks for the idea. If the wife allows me to drive her car I will try and get the test in. Now that I have a scangauge I will try and move it back and forth from test to test to monitor additional information.

The problem is that particular hill is about an hour away for me so hopefully I can find something closer that is comparable.

I didn't have trouble in either vehicle but just found it interesting that the SOC was so different in each of them. I did take the hill twice in her car on Sunday because I thought the first trip up was "strange". Weird how if the software is the same they behave so differently.

I will let you know if I ever get any additional testing or information in.

Thanks again,
Chris

 

I've just experienced my first issue in mountain driving.

Background: Our 2009 touring with about 2,500 miles held 2 adults, 2 golf bags and a suitcase. We were going over Loveland Pass (not the Pass itself but through Eisenhower tunnel) from West to East. The elevation change is from 8,751 feet to 11,013 feet at the tunnel, over a distance of 7.5 miles. The SOC at the bottom was 2 bars below the top. Outside temps were in the 60s and the AC was not running.

Issue: We were going 65mph with the cruise control on. About 1.5 to 2 miles from the tunnel, with the engine racing (as expected), with the SOC down to one blue bar (it was there for a minute or so), and without touching the gas or anything, the cruise control "seemed" to shut off and the car suddenly slowed down, enough that I had to change lanes. The cruise control was still "on" but wasn't doing anything. I got the car to maintain 55 only because I floored the gas.

Lesson Learned: (a) I think I'll stay out of the left lane on long, steep mountain passes like that. (b) I'll watch the SOC and be ready for a power drop after it's been at one bar for a minute or so. (c) All ICEs make less power in thinner air so don't expect the ICE to be able to maintain 65 on steep inclines at these altitudes. And, (4) don't trust the cruise control at times like these.

I did that same route a few weeks ago and didn't have this problem. Perhaps it would've made it at 65 mph if I'd started with a "green" SOC. I don't remember what my beginning SOC was the previous time.

 

Took our 2008 to the TN mountains a year ago, I think the elevation was about 3000-4000'. It drove normal, I was actually impressed with how it did. I noticed that using B on the long downhills, you get great braking from the recharge, until the battery hits all green bars then the engine starts to scream. I guess once the battery is charged, actual "engine" braking is all that you can use! Anyway our mileage there was in the 40's and uphills were no problem, I just put my foot down farther to go faster and tried to ignore the engine noise because aside from sounding like I was in 1st gear it was running great. I'm a FL native so the TN mountains were mountains to me, maybe the mountains you guys are driving in are bigger?

 

I've done that run several times too (in several different rented Prius). It gets noisy and fuel consumption is in the 16-18 MPG range, but no depleted battery. In fact I was surprised to find that the batttery SOC is actually higher after the climb than before. I found that there is a lot of to-ing and fro-ing of battery charge as you climb but the net result is a greater SOC at the top of the climb.