Sudden decrease in MPG

[zharry]

What might cause a sudden decrease in mpg? Was getting 48 and now 39. Does A/C have a major mileage effect? It now very warm in AZ. zharry

[fotomoto]

Does A/C have a major mileage effect? It now very warm in AZ. zharry

 

YUP!   

 

Cooling down a very hot interior and then maintaining it takes a lot of energy and that energy in your hybrid ultimately comes from gas.   TIP:  before getting to the car, push and hold the unlock button on your FOB and it will roll down all four windows letting a lot of that pent up heat escape.  Use recirculation after getting the interior cool so you're not constantly trying to cool the hot incoming air.  

[ScubaDadMiami]

I get about 10 MPG less with air conditioning use. I am not really finding much of a difference by using a higher setting for temperature. As said above, open your windows with the fob before entering the vehicle, drive with the windows down for a minute as you start down the road, blowing the last of the hottest air out before closing the windows. Do not use Auto, and always leave recirculate turned on. If you can possibly stand it, try not to turn on the air conditioner until ICE first turns on. That way, ICE will both charge the battery while also powering during the first operation of the compressor, which, from my observation in My View, draws a lot of juice when it first turns on.

[Jus-A-CMax]

You whimps..turning the ac on when its 100 outside. ;)

 

:flyaway:

[mtb9153]

Having a warm one in the Sillycorn Valley today, must be around a hundred outside.  What a time for my central a/c in the house to be on the blink. :drool:

[Jus-A-CMax]

Having a warm one in the Sillycorn Valley today, must be around a hundred outside.  What a time for my central a/c in the house to be on the blink. :drool:

 

Ewh...thank goodness I ain't coming over :dance:  & :lol:

[ScubaDadMiami]

You whimps..turning the ac on when its 100 outside. ;)

 

:flyaway:

This past winter was the first time without constant AC use in my car since I moved to Florida, in 1981. On the other hand, I dive in a drysuit even when the water is 87F. Even I can't fully reconcile it.

 

Let's see how you handle the 100 percent humidity, before casting sweat drops at us!

Edited June 9, 2014 by ScubaDadMiami

[ptjones]

I'm finding hard to put a number on how much mpg loss there is with A/C use. I think you could safely say 1-5mpg. I think realistically it's in the 1-2mpg range.  I just made a trip to AZ and back, averaged 62.5mph and 46.2mpg using A/C about 1/2 the time at least. :) 

 

Paul

[Cmax lover]

I called Ford about the decrease in mileage....they said to go in and have the updates installed on the car at the dealer.  I did that and the mileage jumped up again but it's still not as high as I was getting.  (49)

[ptjones]

I called Ford about the decrease in mileage....they said to go in and have the updates installed on the car at the dealer.  I did that and the mileage jumped up again but it's still not as high as I was getting.  (49)

49mpg is way better than EPA. :)

 

Paul

[Ponypower]

I wouldn't worry about a loss of a few MPG on those hot muggy days.  I want to be comfortable when driving my CMax. 

[ptjones]

Short distances with A/C on will put you in the 30'smpg. :)

 

Paul

[Cmax lover]

What might cause a sudden decrease in mpg? Was getting 48 and now 39. Does A/C have a major mileage effect? It now very warm in AZ. zharry

Take it in to your dealer and they will do an update on your car.  Tell them you're unhappy with the mpg.  It increased my mileage quite a bit.

[Singoffpitch]

I can get anywhere from 53-57 mpg during my daily 150-mile commute (flat, rural, 2-lane highway running between 55-60 mph for about 140 miles of the drive) in the summer with the windows open. Running the air conditioner drops me to between 42-47. This last winter, I never got above 38 mpg and most of the winter, when temps were well below 0, I was under 30 mpg. I took it in the dealer because I thought something was wrong - I bought a car that was supposed to get 47 mpg and I couldn't get 30 all of a sudden! Then I learned about cold and hybrids... (I even had trouble with my electronics freezing a few times this winter and nothing on the MyTouch would work when it was -40 degrees - dealer said it was due to cold temps). I wish I would have known that it would be such a huge mpg difference when I bought the car only because I had budgeted a 150-mile daily commute based on higher mpg. I guess most people know that without being told. My overall mileage for the car is 42.1 mpg (I bumped up to .1 yesterday) with 39,000 miles from 7/27/13 to now. I love my C-Max, but was very surprised by the huge variance in mpg from 27 to 57 based on outside temperature and using A/C or heat.

[dmk2000]

I can get anywhere from 53-57 mpg during my daily 150-mile commute (flat, rural, 2-lane highway running between 55-60 mph for about 140 miles of the drive) in the summer with the windows open. Running the air conditioner drops me to between 42-47. This last winter, I never got above 38 mpg and most of the winter, when temps were well below 0, I was under 30 mpg. I took it in the dealer because I thought something was wrong - I bought a car that was supposed to get 47 mpg and I couldn't get 30 all of a sudden! Then I learned about cold and hybrids... (I even had trouble with my electronics freezing a few times this winter and nothing on the MyTouch would work when it was -40 degrees - dealer said it was due to cold temps). I wish I would have known that it would be such a huge mpg difference when I bought the car only because I had budgeted a 150-mile daily commute based on higher mpg. I guess most people know that without being told. My overall mileage for the car is 42.1 mpg (I bumped up to .1 yesterday) with 39,000 miles from 7/27/13 to now. I love my C-Max, but was very surprised by the huge variance in mpg from 27 to 57 based on outside temperature and using A/C or heat.

This is true not just for hybrids. I lose about 4 mpg in winter even without such extreme temperatures on old good ICE. Do not forget that in a winter month gasoline blend also responsible for a mileage drop. 

[SnowStorm]

Select Accessory and Climate power on the MyView screen and you can see how many kilowatts the A/C is using.  Very helpful.  I have seen it start at 3 kW and eventually settle down to just 300 watts.  My summary for low A/C power is (pardon the repetition):

1. Use recirculate.  Sometimes it turns off after 5 minutes.  Turn it back on.  The power difference between outside and recirc can be huge.
2. Turn up the fan.  More air flow feels cooler and uses very little energy compared to the compressor.
3. Turn up the temperature as far as your comfort level allows.  I use 75 or 76F - and use it as soon as I turn it on.  A/C power is proportional to the difference between outside temperature (air over the condenser) and inside temperature (air over the evaporator).  Use more fan to offset higher temperature setting.
4. Close unused vents (don't forget the back seat!).  The goal is to cool you, not the car.  For just myself, I close back seat vent and passenger vent next to door.  Then I point the other passenger vent towards me.
5. Control heat build up.  Use windshield screen, close pano roof shade, park in the shade, etc.  At work I can often park next to a building that gives afternoon shade.  Its amazing how much cooler a car is - even though in the sun most of the day.  Remove hot air as others have described.

Admittedly, my A/C use is "moderate" but I don't think the hit is more than 1 or 2 mpg.

[Singoffpitch]

Select Accessory and Climate power on the MyView screen and you can see how many kilowatts the A/C is using. Very helpful. I have seen it start at 3 kW and eventually settle down to just 300 watts. My summary for low A/C power is (pardon the repetition):[list=

SnowStorm, can you tell me how/where to find the Accessory & Climate power thing? Is the MyView screen the big screen in the middle of the dash? I couldn't find anything for accessory or climate when I tried to do this today. I went to the climate screen, but it only has settings for climate and no power info. I couldn't find it in any other settings menu I checked, either. I thought maybe I had the wrong screen and you meant the ones in front of the driver, but I couldn't find it there, either. I am curious to see how my different settings affect kW usage. I learned to drive my hybrid most efficiently by using the car picture on the screen that showed me every time it flipped from electric to gas (and tells why) until I figured out all the little ways to keep it running EV. I'd like to finesse my accessory usage, as well! Thanks for the other great tips!

Edited August 23, 2014 by Singoffpitch

[ScubaDadMiami]

Select Accessory and Climate power on the MyView screen and you can see how many kilowatts the A/C is using.  Very helpful.  I have seen it start at 3 kW and eventually settle down to just 300 watts.  My summary for low A/C power is (pardon the repetition):

1. Use recirculate.  Sometimes it turns off after 5 minutes.  Turn it back on.  The power difference between outside and recirc can be huge.
2. Turn up the fan.  More air flow feels cooler and uses very little energy compared to the compressor.
3. Turn up the temperature as far as your comfort level allows.  I use 75 or 76F - and use it as soon as I turn it on.  A/C power is proportional to the difference between outside temperature (air over the condenser) and inside temperature (air over the evaporator).  Use more fan to offset higher temperature setting.
4. Close unused vents (don't forget the back seat!).  The goal is to cool you, not the car.  For just myself, I close back seat vent and passenger vent next to door.  Then I point the other passenger vent towards me.
5. Control heat build up.  Use windshield screen, close pano roof shade, park in the shade, etc.  At work I can often park next to a building that gives afternoon shade.  Its amazing how much cooler a car is - even though in the sun most of the day.  Remove hot air as others have described.

Admittedly, my A/C use is "moderate" but I don't think the hit is more than 1 or 2 mpg.

+1, with a few things that I do differently.

 

1.  I strongly agree: always leave recirculate on. It makes a big difference.

 

I have never had recirculate turn off. If you have the A/C to set to Auto, that could be the reason. I never use Auto. Auto is not your friend.

 

Especially at this time of year, I have A/C running 100 percent of the time, so I don't bother turning it off and on for vehicle shut downs. That way, it is still with recirc turned on when I start up. About the only thing I ever do is to change the fan speed, and perhaps move the temperature setting up or down a degree from 74F.

 

2.  Regarding the fan, absolutely agreed. At least in the short run, you get way more bang for the buck by using a higher fan speed than you do by reducing the temperature with a lower fan speed, especially when initially cooling off the cabin. I think that after five or six bars of fan speed, there is a slight tick up on how fast you drain the HVB, but it is not a big deal, and it is a better alternative to lowering the temperature, at least in the shorter run.

 

3. Agreed about temperature setting, especially in the short run. If you are traveling over great distances, it matters less, so long as you set within a reasonable comfort zone, such as 72-75F.

 

4.  I have never tried closing vents. I almost always have the dog with me. Also, admittedly, I am a bit of an air conditioner-aholic. I distribute the cool air equally but while also keeping myself comfortable.

 

5.  As said, whenever possible, park in the shade. I got my windows tinted. If you have to let your car sit out in the sun, when you approach your car, hold down the unlock button on the key fob until the windows open. Pull out of your destination with windows open, allowing the breeze to remove hot cabin air. Close the windows.

 

 

I have done a great deal of testing (using only My View, not some sophisticated equipment) on air conditioner use with my C-MAX. What I will add to what SnowStorm brings up are the following observations:

 

When A/C first starts, it spikes in draw from the battery. During this period, it really doesn't matter how you have set the A/C, and I have not found a combination of temperature/fan that draws less during that first kick-on time. However, if you have set a very low temperature for your start-up, that spike will last for a bit longer while the cabin gets its initial cooling. So, initially setting a somewhat higher temperature will give you a slight benefit to your fuel economy.

 

After that, things settle down, and you will see a lower and consistent draw. Playing around with temperature and fan speed at that point really doesn't change the draw very much. However, I only say this after playing around with reasonable temperature settings, which for me usually run about 73-75F. If you turn it all the way down to LO, I can't say whether that is still true or not.

 

 

SnowStorm, can you tell me how/where to find the Accessory & Climate power thing? Is the MyView screen the big screen in the middle of the dash? I couldn't find anything for accessory or climate when I tried to do this today.

First, we are talking about the left hand side smaller screen. Using the arrow/OK button on the left side of the steering wheel, scroll until you get to My View, and then OK that. Now, again using the left side of your steering wheel, press on the right arrow to change My View. You can change either the left side of the screen or the right. However, not all things are available to each side. The power use that involves Climate is for the right half of that left hand side screen. Scroll to that and OK it. It looks like three white horizontal bars.

Edited August 23, 2014 by ScubaDadMiami

[RobMax]

I noticed ScubaDadMiami said he tinted his windows and has an upper-level SEL. I hadn't noticed until we drove our car home that window tint wasn't installed on our lowly SE. After researching whether there was an option, I discovered there isn't likely because of the "passenger car" classification of the C-Max. Sounds odd, but I'll be getting mine done locally shortly just to keep the interior cooler (and prying eyes out of the back) for less than $250 total. I've always had vehicles that had tinted windows in CA, but looking back they were always minivans or SUVs (even our FEH) where that option was apparently legal in CA.

 

OP, there's no way I'd live in AZ without complete black-out tint on any vehicle. LOL

Edited August 25, 2014 by RobMax

[DaveofDurham]

SnowStorm, can you tell me how/where to find the Accessory & Climate power thing? Is the MyView screen the big screen in the middle of the dash? I couldn't find anything for accessory or climate when I tried to do this today. I went to the climate screen, but it only has settings for climate and no power info. I couldn't find it in any other settings menu I checked, either. I thought maybe I had the wrong screen and you meant the ones in front of the driver, but I couldn't find it there, either. I am curious to see how my different settings affect kW usage. I learned to drive my hybrid most efficiently by using the car picture on the screen that showed me every time it flipped from electric to gas (and tells why) until I figured out all the little ways to keep it running EV. I'd like to finesse my accessory usage, as well! Thanks for the other great tips!

My View is one of the options on the small screen to the left of your speedometer (the small screen that is controlled by the arrow buttons on the left side of the steering wheel) and Accessory/Climate power is one of the options in My View.  See pages 117 and 119-121 of the manual.