So here are my observations from yesterday.

Temp 104
First 8 minutes of the drive I'm driving windows up A/C on ECON 78 degrees. The RPMs are normal like any 75 degree day. I am accelerating at 1600-1800 RPMs just like always. Then after about 8 minutes the RPMs suddenly shoot up from 1500 to 2100 while running at 40-45 mph.
I then shut the A/C off and roll down the windows. When I come up to the light the car cuts into EV.
My observation: Until the car is ready for EV it won't go into this extra 500 RPM thing.

Has anyone else noticed this? It was quite odd and I will check again on my drive home this afternoon.

So all this conjecture about it running b/c it works harder, etc doesn't make much sense when it waited 8 minutes on my drive yesterday before it went into this issue.

Also - if it is an argument of the A/C working harder b/c it is hotter I don't buy it. I have a very nice tint on my windows.

 

My 2007 FEH also did this in the cold, but is was below 20 or 25 degrees I think. There's another thread somewhere here about this. Have't had the 2009 in temps that cold yet to see if it does the same. It was very similar, press the pedal at all, and the RPM shot up 500 RPM or more.

-- Rick

 

Regarding A/C systems working harder as temps go up.

The engineering of these systems says that as the heat rejection temp (ie air temp flowing thru the A/C radiator) goes up the amount of work to produce a given amount of cooling effect goes up.

Don't believe it if you don't want to, but that's the engineering. Look up the Carnot cycle for heat engines (the A/C is a heat engine too) and see what happens to the efficiency of the cycle as the rejection temp rises.

 

So what you are saying is that the cut off point will not be invoked by the software unless the FEH is warmed up.

I could understand if this were the first couple of minutes first thing in the AM, when the FEH uses a lot of electric drive. You can tell because the SOC goes down, while the TPS stays at a set level, even when accelerating. Once the FEH gets to either SOC = 40 OR I stop at a stop light, then the engine reverts to normal RPMs.

On my 2008, this "initial behavior" has never lasted more than 2 minutes, but I don't know about the 2008.

 

That is exactly what I am saying - or in this case cooled down I guess. I'm not sure if it makes sense or why but that is what has happened the last two days.

It did it again today on the drive home. This time I was paying even more attention. At about 6-7 minutes into the drive (temps like 106-108) the RPMs went from 1500 cruising down the road at 45 mph to 2100. That is when I turned my A/C off and rolled down the windows... When I slowed down under 40 I double tapped the brake and it went into EV...

It is kinda nice actually. I can cool off the car with the A/C during the first part of the drive and then I know when the car is ready for EV so I don't have to "try and see" if it is... I hate double hitting the brake at 40 if I am not going into EV.

 

Yup, must be nice, unfortunately every time my family is in the car, the A/C is MANDATORY...

 

Hmmm, this is not the case with my hybrid, and I own a 2008 as well, although mine is AWD. The past few days I have been noticing that the high RPMs will occur when the temperature has cooled down after I have driven on a hot day. Yesterday it happened when the ext temp was 86 F. I had the high RPMS for about 10 minutes, then it suddenly stopped. It makes me wonder if it isn't battery temp.

However, the battery temp programming for my SGII did not work when I tried it, so I can't monitor the temperature.

Has anyone found a code that works for the SGII, to monitor the battery pack temp? The one in the instruction page on line does not work.

 

Three way...

Hot day, the cabin needs to be cooled as does the battery. "Turn off" any one of these and the compressor doesn't need to pump extra volume.

 

I have no idea what the issue is. Perhaps AWD v. 2WD? That is odd. At 86 my car is at the best temperature (really anything about 77-94 is great). Even in the morning after not being driven for 12 hours my car would "warm up" and be into EV mode in under 5 minutes at that temperature and during the "warm up" the RPMs would be normal.

Is it more humid in LA than Vegas (I presume...)? Could that have something to do with it? In the morning in Vegas this time of year humidity is around 10-15%, afternoons it's between 5-10%.

I am in FL and GA right now (vacation) so I have no new observations other than the fact that I think my hybrid would tear up the roads out here. All the speed limits in Valdosta are 35 and there are just enough slightly rolling hills that I think the hybrid could really take advantage of it. Add in the fact that all the highways (other than interstates) are 55 and I would be getting 40+ mpg tanks pretty regularly I think.

 

Yes, it is more humid, around 26% just now.

My vehicle is generally the same - OK at below 95. But the behavior I have listed occurs AFTER the vehicle has been driven at high temperatures, for example driving to supper in the late afternoon, followed by going home after dark. It makes me wonder if it isn't battery related.