Went to the mountains in our Prius

There is absolutely no problem with going down to 2 pink bars... It happens all the time, even in normal everyday flat traffic. That is completely within the normal range of operation for the Prius, so you needn't worry about that! It won't let the car go any lower than what it's designed for...

As for the recirc/fresh thing, that sounds very odd to me also... Hopefully one of the more techie types can theorize on the behavior you saw...

-Vikki

 

Actually you may have helped. Sometimes climbing mountains the reduced air pressure messes up the climate control system. Cycling through different climate settings undoes the problem.

Im new to the Prius, but in one of my trucks had "issues" on I-70 going from Utah to Colorado and when I turned off the AC you could hear the vacuum going away. I turned the AC right back on and no more issues.

 

<div class='quotetop'>QUOTE(jendbbay @ Jul 31 2007, 05:27 PM) [snapback]488393[/snapback]</div>

When you switched to "fresh" and the power came back did you still have the two purple bars? Could you have turned the A/C off? Also, how many people in the car?
I was at same altitude with four adults and had very little power up a longer grade. I'm trying to get some correlation between power and air conditioner mode. On the surface, there doesn't seem to be any.

 

Hi Jendbbay,

My guess is that with multiple people in the car, and recirc on, is that the humidity in the air built up. And the car was trying to use the AC as a dehumifier, by running the condensor very cold. The extra AC electricty load pulled down the battery. It appears (appears only) that turning off the Recirc in this situation resulted in the AC being used to cool the outdoor air, which seems to require less AC electric load than dehumidifying the interior air. Which might be the case in the mountains, as the outdoor air is less dense, and much drier than near sea level.

Again, this is only a guess.

 

<div class='quotetop'>QUOTE(jendbbay @ Jul 31 2007, 08:27 PM) [snapback]488393[/snapback]</div>

Hi Jen,

I assume by "loss of power" you mean the acceleration was a lot weaker than normal...?

As you know, the Prius uses the high-torque electric motor to provide the low-speed acceleration, since the engine (ICE) has very little torque. If your battery is low, then the car has little to power the electric motor, and the result is much weaker acceleration.

Climbing hills draws extra power, as does the A/C. I believe the recirc draws even more (the dealer always uses Max A/C with recirc to drain the battery for testing :huh: ), though perhaps someone with more technical insight can confirm that.

It simply sounds like you reached a condition where the battery was near empty and you had temporary weak acceleration until either the load was reduced or battery charge was built.

Either way, it sounds like your Prius was operating exactly as designed, and I wouldn't worry about it. B)

 

Note that my 2007 Prius Touring gets 8 to 10 mpg less when AC is on and the ICE (internal combusion engine - i.e. gas engine) is on.

 

Contributing factors:

1) Sounds like you had your poor Prius loaded down with stuff, hubby or wife and camping equip adding weight to what it had to pull up the hill.

2) Any gas engine (and person) will have less power at higher altitudes due to decreased air available. 8700 ft is pretty high.

Yes, the AC will pull your battery down to pink (purple), but like others said it won't hurt anything, the computer babies the battery. At pink the battery still has around 40% charge. Mine always goes pink at McWendy's drivethrough... Here if there are only 3 cars in front of you it will still take 15 minutes to get up to the window and the AC will pull the battery down. Then every time the car moves a little the ICE will come on. You will have less power when you hit the street because the battery is not providing much if any power, it's mostly up to the ICE. But it should recover within 5-10 minutes with normal driving. I hadn't heard the theory about AC recirc/fresh... with mine the computer decides which to use. When I first got this car I tried to adjust the AC and Heater... after a few weeks I gave up and just started leaving it on auto set points or turning it off because it seems to have a mind of its own. Forget turning off AC and going to just outside air with no AC (you gotta push about 6 buttons and lower the temp all the way), mine always blows warm anyway unless its below about 60 degrees. One of my few pet peaves with this car.

 

<div class='quotetop'>QUOTE(OlsonBW @ Aug 1 2007, 12:18 PM) [snapback]488766[/snapback]</div>

What do you normally get? I'm in Las Vegas, and my 07 Touring went from 46 to 42 when I started running the AC full time, and I bet my AC has to work harder.

 

i just turn off a/c when climbing hills problem solved

 

<div class='quotetop'>QUOTE(Spoid @ Aug 1 2007, 02:05 PM) [snapback]488858[/snapback]</div>

Here in Seattle I was getting around 51.4 mpg (55-75 degrees) and it quickly dropped to 50.3 (75 to 95 degrees) sparingly using AC (meaning until my wife really complains about it being too hot in the car - when she cools off I turn it back off again). If AC was kept on all the time we would be averaging at best low to mid 40s.

Keep in mind that there are no flat areas of Seattle and also that Seattle ranks as some of the worst stop and stay stopped and move a little, ok go, no stop, traffic in the country.

Forecast for the next 7 days is mid 70s to low 80s. It was 88 degrees yesterday afternoon. Yes, in Seattle.

 

I wonder if this is something related to older Prius cars or maybe my battery is loosing capacity but on my car if I am lugging up a mountain I commonly see 1 bar.

I was never really concerned unitl I have noticed many saying that there battery never goes below 2 bars.

On the same subject I am also curious if anybody has seen no bars as I have never seen this condition.

When I get down to 1 bar you can hear my engine working much harder though.

 

<div class='quotetop'>QUOTE(bmwquickspeed @ Aug 3 2007, 01:06 PM) [snapback]490110[/snapback]</div>

Unless you have over 150,000 miles on your Prius I wouldn't even begin to worry about your batteries (or gas engine for that matter) on your Prius. It's made by Toyota or conforms to Toyota quality standards.

 

<div class='quotetop'>QUOTE(bmwquickspeed @ Aug 3 2007, 01:06 PM) [snapback]490110[/snapback]</div>

If I leave my foot on the pedal going up the Coquihalla Hwy, the SOC drops down to 26%, which would probably be 1

 

If the Prius cannot go to the mountain then the mountain must come to the Prius.

 

Yesterday I was out with my wife on a little mini-roadtrip to Lafayette (we're in Fremont, so it's only about 30 miles or so away) and I encountered something that might be similar. The trip there was just fine, but when we got out of the car we noted the temperature differential between Fremont, which is near the bay, and Lafayette, which is pretty far up into the hills from Oakland and Berkeley. It can't have been more than 80 when we left Fremont but somehow it was in the upper 90s in Lafayette.

Anyway, we left going down CA-24 and the interior of the car was hot, so the Prius had A/C and recirc on. I think it was going down CA-24, anyway; it seemed like no matter how much I stepped on the gas (up to 3500rpm) the Prius couldn't keep its speed. I dropped from 53.3 to 53.1 mpg in a 5-minute stretch. I guess maybe in that area you are climbing a hill, since after a litttle while we hit the Caldecott and the real downhill portion and all of a sudden I was maintaining 75 even without warp stealth.

I'm going on a roadtrip up I-80 to SLC and beyond next week, so it'll be interesting to see what happens.

 

<div class='quotetop'>QUOTE(jendbbay @ Aug 2 2007, 04:12 AM) [snapback]489154[/snapback]</div>

So let's see: Partway up the mountain you switched from recirc to fresh, and at the same time the outside temperature was dropping from 94 degrees down to the high 70s - and yet, somehow, you people are trying to attribute the additional available power to the dehumidification aspects of air conditioning? :huh:

IF changing from recirc to fresh had any affect on the car's performance, I doubt it had anything to do with dehumidification.
Dehumidification happens when warm moist air come in contact with the cold fins of the evaporator unit. This happens whether the car is in recirc or fresh air mode.

If anything, if we are going to try to attribute the increased performance on changing from recirc to fresh air, my guess would be the extra cool air being blown through the traction battery helping keep it cool. If you are forcing air into the car, it also needs to escape, and the traction battery vent is the most logical place.

By the way, do you remember hearing the traction battery cooling fan while you were experiencing sluggish performance?

Overall, I think the drop in outside temperature was the major factor in increasing available power.

 

Hi Sufferin..

Who is insisting on anything? Your quote was not in the original post, or before any post I made. The system probably works to ensure comfort level. So, with lower temp, higher humidity might still be a net confort level improvment. AND, I did leave the posibility open in my post regarding thermal load change, without specifically mentioning it. That was in my thinking as a possibility when I wrote it. But, I wrote the comment as if the OP had been complete in her original description, and had told us the whole set of facts. Specifically, the temperature was still 94 F when she opened recirc.

Another thing is that the amount of water vapor air can hold at higher altitude and lower temperatue is less (in both cases). There is less water vapor in 70 degree 50 % R.H. air than 94 F 50 % R.H. air. So, flowing outside air inside would automatically dehumidify the cabin, not only by dilution, but difusion. Besides cooling the cabin air, as the outside air is now cooler.

So, dehumdification could still be the issue. As why did the AC still pull lots of power when the recirc was closed? If the air was cool outside, the thermal performance of the AC would have been allot better. But she reports only after opening recirc did vehicle power improve.

The AC could have still dropped out of dehumidification mode, and even turned the compressor off, as all cooling and dehumidification would have been provided by ventilation.

The hypothesis here is that an automatic dehumidication mode could still be the root cause of the high AC power demand in this case.

 

<div class='quotetop'>QUOTE(donee @ Aug 5 2007, 04:08 PM) [snapback]491001[/snapback]</div>

OK, that makes sense too . . . BUT . . . the OP was driving across the Sacramento/San Joaquin (pronounced Wah-keene) Valley and into the Sierra during the summer . . . an area of the country know for its low humidity - especially on the days when the temperatures are in the 90s or 100s.

In high humidity areas, I could see where leaving recirc on would make sense.

I normally run the AC at about 80 degrees, fan on fairly high, and fresh air. To me, that is more comfortable than having slower moving very cold air blowing from the vents . . . but I don't know what would be the best settings for high temperature, high humidity areas . . . never been there in a Prius.