AC temp and compressor load

[DaveofDurham]

We had our first 80+ degree day today so I was thinking about (but didn't use) the AC.

 

I am wondering about what changes when I turn the temp control up and down when the AC is running.  For example, if I turn the AC on and turn the temp setting all the way down I think the interior will get really cold.  If I get too cold and turn the temp setting up to say 72 degrees does that (a) result in the AC compressor working less hard/less often (because I am asking for less cooling) and using less energy, or (b) the AC compressor keeps working just as hard and just as often at 72 degrees as when the temp was turned all the way down and the passenger cabin temp is adjusted upward by the heater working at the same time the AC is working.

 

My previous car was a 2000 Honda Insight and after years of thinking it worked like (a), I had someone tell me it worked like (b) and that I should always select the lowest temp setting when I was running the AC and just turn the AC off for a few minutes when I got too cold.  I have no idea if what I was told was correct.   If the C-Max works like (b) then when the AC was on and the temp was set at 72 there would be heat being pulled out of the coolant and the engine would be running cooler and we might be talking about putting on grill covers in July and August.

[ceemax71]

Great question.

 

The C-Max hybrid air conditioner compressor is powered by a variable speed electric motor. 

The compressor does not cycle on and off to match demand like on a traditional vehicle.

 

The higher the cooling demand the faster the compressor motor runs.

So lowering the thermostat setting will require a higher compressor speed resulting in higher energy usage.

Likewise, a higher ambient temperature results in higher energy usage.

 

The climate control system measures the sun intensity to adjust cooling also.

[rfruth]

Good explanation 71, I've wondered about this but had no idea - tnx,  you sound so sure, how do you know, inside info, have access to the theory of operation ?  (I have no reason to doubt U)   

[ceemax71]

This is from the C-Max workshop manual.  (Section 412-00 climate control system operation and component description.)

 

I had no idea either until I read about it in the manual.

[C-MAXER]

Another nice benefit of this type of system being electronic and computer controlled is it doesn't go to full speed immediately blasting you with hot air; instead ramping up the fan speed as the cooling becomes available.   NOTE:  this is in auto.  I haven't tried the Max A/C setting yet which will get plenty of use this summer (sigh.....).

[viajero]

One of the options in the MyView screen is accessory and climate power use.  It gives you a nice big graph, so you can see just how much power the A/C or heater is using under what conditions.

 

All the 12 V accessories have a separate graph.  That's pretty much everthing but the A/C or heater - stereo, lights, fans, plug-ins...

[DaveofDurham]

One of the options in the MyView screen is accessory and climate power use.  It gives you a nice big graph, so you can see just how much power the A/C or heater is using under what conditions.

 

All the 12 V accessories have a separate graph.  That's pretty much everthing but the A/C or heater - stereo, lights, fans, plug-ins...

 

Thanks for the reminder.  I had forgotten about this option of MyView.  I will test it out on Tuesday or Wednesday when we are supposed to have high temps in the 80's.

[11StiLimited]

I REALLY need to read up on the MyView thing.  I had no idea so many options were available for display.

[fotomoto]

I REALLY need to read up on the MyView thing.  I had no idea so many options were available for display.

 

Having owned three other hybrids that offered precious little info, being able to choose an engine temperature or tachometer display is awesome!   I wish we could have 2 or 3 separate My View screens just like having a trip 1&2.  Or better yet, a much larger left screen that could display every option at once or be reduced to one's personal preferences.  Now that would be COOL!

[DaveofDurham]

Having owned three other hybrids that offered precious little info, being able to choose an engine temperature or tachometer display is awesome!   I wish we could have 2 or 3 separate My View screens just like having a trip 1&2.  Or better yet, a much larger left screen that could display every option at once or be reduced to one's personal preferences.  Now that would be COOL!

Or an option to display some of this info on the right screen in place of the deficiency leaves.

[C-Maxgo]

Fhotomoto, just curious why you sold your Volt? I thought about buying it before the C-Max purchase.

[fotomoto]

Fhotomoto, just curious why you sold your Volt? I thought about buying it before the C-Max purchase.

 

In one word:  room.  My family situation changed to the point I needed a more "family car".  Of course it was going to be a hybrid so it came down to the C-Max and Prius V and the 'max won out. :wub2:    Neither will come close to the crazy mileage I got in the Volt:  162mpg lifetime!  It was very tough giving up electric drive.  It's the future.  :worship:   We will need to replace my wife's car in the next 3 years and it will be another plug-in.

[Jus-A-CMax]

In one word:  room.  My family situation changed to the point I needed a more "family car".  Of course it was going to be a hybrid so it came down to the C-Max and Prius V and the 'max won out. :wub2:    Neither will come close to the crazy mileage I got in the Volt:  162mpg lifetime!  It was very tough giving up electric drive.  It's the future.  :worship:   We will need to replace my wife's car in the next 3 years and it will be another plug-in.

You had a Volt?!?!? Wow...I thought those cars were great....what are the real world range of those cars, if u don't mind me asking? 

[fotomoto]

You had a Volt?!?!? Wow...I thought those cars were great....what are the real world range of those cars, if u don't mind me asking? 

 

Yes, they are GREAT cars!  I'm assuming you mean battery/EV range.  If so, my 2012 was rated at 35 miles but I regularly got 42-44 and never dipped below 39 estimated the entire time of ownership.  Folks in your area can get 50+ miles plus the coveted HOV access.  I had a level 2 charger that allows 5 miles/hr charging so I could get even more range quickly.  My best ever EV only day was 82 miles (2.5 charges).  My best range off one battery charge was 62 miles (30mph avg).  My best tank (8gal) lasted 6 weeks and 2400 miles.  The gas generator usually avg about 39mpg but I rarely used it (1,000 miles over 6 months).  Plug-ins are a whole new ball game.

Edited April 20, 2013 by fotomoto

[Jus-A-CMax]

Yes, they are GREAT cars!  I'm assuming you mean battery/EV range.  If so, my 2012 was rated at 35 miles but I regularly got 42-44 and never dipped below 39 estimated the entire time of ownership.  Folks in your area can get 50+ miles plus the coveted HOV access.  I had a level 2 charger that allows 5 miles/hr charging so I could get even more range quickly.  My best ever EV only day was 82 miles (2.5 charges).  My best range off one battery charge was 62 miles (30mph avg).  My best tank (8gal) lasted 6 weeks and 2400 miles.  The gas generator usually avg about 39mpg but I rarely used it (1,000 miles over 6 months).  Plug-ins are a whole new ball game.

Thanks for the update fotomoto...didn't realize how good the MPG was... :worship:  6 weeks and 2400 miles off 8 gallons...holy cr*ap  :rockon:  Now my CMax feels like a giant gas guzzling SUV....oh noes...... :runaway:

 

 

PS it wont work for me - I cannot fit all my ski/board stuff into a Volt but those miles, thats at least 4 trips there in 1 tank, theoretically.

Edited April 20, 2013 by Jus-A-CMax

[wab]

Yes, they are GREAT cars!  I'm assuming you mean battery/EV range.  If so, my 2012 was rated at 35 miles but I regularly got 42-44 and never dipped below 39 estimated the entire time of ownership.  Folks in your area can get 50+ miles plus the coveted HOV access.  I had a level 2 charger that allows 5 miles/hr charging so I could get even more range quickly.  My best ever EV only day was 82 miles (2.5 charges).  My best range off one battery charge was 62 miles (30mph avg).  My best tank (8gal) lasted 6 weeks and 2400 miles.  The gas generator usually avg about 39mpg but I rarely used it (1,000 miles over 6 months).  Plug-ins are a whole new ball game.

 

I was looking on Fuelly.com for the Volt.

Anybody know why I can't find it???

 

It shows up when I google "fuelly volt" 17,400 hits,

https://www.google.com/search?as_q=fuelly+volt&as_epq=&as_oq=&as_eq=&as_nlo=&as_nhi=&lr=&cr=&as_qdr=all&as_sitesearch=&as_occt=any&safe=images&tbs=&as_filetype=&as_rights=

 

but doesn't appear under Chevrolet.

http://www.fuelly.com/car/

 

thanks

[zhackwyatt]

I was looking on Fuelly.com for the Volt.

Anybody know why I can't find it???

 

It shows up when I google "fuelly volt" 17,400 hits,

https://www.google.com/search?as_q=fuelly+volt&as_epq=&as_oq=&as_eq=&as_nlo=&as_nhi=&lr=&cr=&as_qdr=all&as_sitesearch=&as_occt=any&safe=images&tbs=&as_filetype=&as_rights=

 

but doesn't appear under Chevrolet.

http://www.fuelly.com/car/

 

thanks

 

From the FAQ: http://www.fuelly.com/faq/?full=1 

 

What vehicles won't work at Fuelly?

Fuelly is built to track vehicles from motorcycles and scooters up to a standard SUV. All of our assumptions are based on the idea that the vehicle will use liquid fuel in a single tank. Anything outside of that range won't work at the site.

 

That means Fuelly can't track electric vehicles like the Plug-in Prius or Chevy Volt. (If you have a Volt, try voltstats.net instead.) Fuelly also can't track commercial trucks, Bi-fuel vehicles, RVs, motorhomes, or lawn equipment.

I don't really quite understand their reasoning. They track the C-Max Energi which operates on the same concept as the Volt.

[wab]

From the FAQ: http://www.fuelly.com/faq/?full=1 

 

I don't really quite understand their reasoning. They track the C-Max Energi which operates on the same concept as the Volt.

Saw the FAQ

 

sschhh I think it's a Prius thing, but you didn't hear it from me.