Another hot humid day here. Any tips on A/C usage?

[obrother]

I just can't drive without a/c when it gets hot and humid. It's just not an option for me to roll down the windows. Anyone know if the a/c compressor switches on and off(cycles) according to the temperature you set on the dial? Or is the compressor of the variable speed type? What's the difference when you use MAX ? It really does a good job compared to a/c with MAX off. Should I just set the cool temperature to where it's just barely comfortable to save on range or does it matter? Should I just set MAX, full fan and lowest temp on the dial? Most of the time I use the top vents only, and recirc for the best cooling. Does using 'auto' make any difference on range? The owner's manual says not to use MAX for long as it will have a large impact on range. It's my first summer for me with my 2012. Anyone's knowledge and experience would be much appreciated. Maybe someone has some caniOn data for technical proof of how the miev works. Thanks!

 

[kiev]

Oh brother where art thou?

Here's what i do with the AC and drive 40 to 60 miles per day, and in the morning the RR shows from 67 to 90 miles after charging overnight:

i press Max and leave it on all the time, with the temp setting about two clicks into the cold zone, plus turn the middle fan knob all the way on with inside air recirculate, and i set the bottom knob to blow out top vents and halfway to bottom. Then i just use the AC to cut the heat and humidity to a tolerable level, and to do this just press the middle button to cycle the AC Off while leaving the Max and fan blasting away. Then after several minutes and the temp and humidity get back up, press the middle button to turn AC On for a couple of minutes. This method uses less power than running the compressor all the time, and the Max fan runs off 12V so it doesn't really hurt range. It's a little noisy and loud but worth it in my opinion.

 

[mdbuilder]

Max draws approximate'y 1.8 Kw, 1,800 watts. Low power in auto mode about 450 if I remember the screen data correctly.

I am in and out of my car several times a day driving a 1/2 mile across campus, I'll hit max as the car starts to move to quickly cool things down then click max off and go to auto to maintain. Auto + the coldest setting will not draw much if the air temp is say 80, if it is 95+ it takes more power.

Such usage over 2 days which is a 7 mile commute *4 (14 per day) + 8 to ten of those short trips where the car is smoking hot when you hop in and needs max for a minute or two just to make it tolerable cuts about ten miles off my range. I can do 45 miles over two days and arrive home with at least 14 and 4 bars still showing.

 

[Don]

The compressor cuts in and out to regulate the temperature of the evaporator, based on where you have the temp dial set. If you have the dial at max, then the compressor runs more often and for longer periods of time than if you have it set lower. Also, if you have the fan speed set on max, then the compressor runs more often and for longer periods of time than if you had the fan at half speed, because the fan is blowing more warm air through the evaporator, so the system must pump more energy into the evaporator to keep it's temperature where you have it set. The more cold you carry away, the more cold the A/C system must generate so the larger percentage of time the compressor will run - If you push the button for 'MAX Cool, I think it runs continuously

We use th A/C every single day for about 9 months of the year down here too and it's not as big an energy user as you might think. It's about a 15% hit to the range of the car, and that's factored into the computations of the RR gauge - Turn the A/C on and off while watching the RR gauge and you'll see about how much range you'll use from your current battery charge

Don

 

[obrother]

I just got some info from canIon. Yes the compressor seems to have different speeds. So setting the thermostat dial to the lowest comfortable setting will increase range. Using MAX turns the compressor on full power no matter what the temperature in the cabin is. Thanks for the quick replies guys. kiev I'm over hear just west of Toronto Ontario Canada. Finally some info on how to set my a/c. It looks like the compressor runs between approximately 400 and 800 watts if canIon is correct. MAX like you guys said is great for quick cooling or when it's really hot out, or when its really cold to get the compressor running. Otherwise I will leave MAX off and try adjust the temperature dial to the lowest comfortable setting. Recirc on of course and upper vents only. The fan speed will work kinda like the temp setting as the more fan speed the more of the car that will get cooled and the longer the compressor will run or run at the higher output. I posted a screen capture from canIon. Let me know if it didn't work. You should see a thumb pic and when you click it... it will open the pic on its' website.

 

[PV1]

Pressing MAX overrides temperature and fan settings. Even if the temperature dial is on the green dot with the A/C light on, pressing MAX will be like turning the temp dial all the way to C. The same goes for the heater on MAX.

What I've done lately is simply leave the temp dial on the green dot (if you ran heat beforehand, turn it one click into the blue and back to the dot to bypass the heater core), press the A/C button, and vary the fan speed based on how much cooling I need. I find this provides ample cooling with minimal range impact.

Turning the temperature knob closer to C adjusts the evaporator temperature to be progressively colder. The compressor will cycle on/off and/or vary speed to maintain that temperature. So, for a given temperature setting, the compressor will run more to maintain the set temperature with higher fan speeds. For a given fan speed, the compressor doesn't run that much more to maintain a colder temperature vs. a warmer temperature. Evaporator temperature is a function of the pressure difference between the condenser (outside coil) and evaporator (inside coil). The compressor does run more at first to achieve the higher pressure difference, but it doesn't take much more to maintain that pressure compared to a lower pressure. That's why fan speed varies the RR number with A/C on and temperature really doesn't. MAX, however, overrides the dials and sets both fan speed and temperature to the extremes.

 

[mdbuilder]

Today I started with a full charge and 70 miles on the meter ac off, 65 ac on (auto setting not max). Did my 12 mile morning trip around town when it was 82f, then a shopping trip in the afternoon at 91F to bring the mileage total up to 41. 21 left on the meter ac on and 24 ac off.

Not bad, could have gone a total of 62 miles - 41+21. Ac was on at all times, temp all the way to cold, fan and vent settings on auto for all but a couple minutes when I went to max. Moderate driving mostly at 45-50 with a little bit no faster than 55 max.

 

[Aerowhatt]

Everybody has their own way of doing things. So here is mine gleaned from multiple hot weather (90's to 102F) trips to the mountains here.

The round trip is between 59 and 73 miles depending on what destination is chosen (50% freeway, 30% highway, 20% winding mountain "highway"). With elevation changes of 2900 ft up to 5600 ft, depending on what destination is chosen. After experimenting, I have found the most comfort and (perceived) least power consumption for running the AC with the temperature control set at the coldest setting and varying the fan speed in the lower ranges to maintain comfort.

The biggest adjustment for me was paying more attention to the temp in the car. With an ICE, I often would not cut back the AC until a chill brought it to my attention. In an EV this would be very wasteful. I mostly drive with the temperature comfortable not just "tolerable". Often while up in the mountains the AC button can be pushed to turn the compressor function off, leaving the fan on low or mid setting to continue to pull the cool out of the evaporator coil until the air warms enough to push the AC back on for a while. I find this to be much more comfortable and use less power overall than running a bunch of airflow at a warmer temperature control setting. Humidity is generally lower here than some places which allows the AC to work more efficiently at cooling the interior, than if the humidity was really high. Recirculate setting of course, so you are Re cooling, cooler, already dried air, instead of warmer, moister outside air.

Colder air coming from the vents more slowly does a better job of making most people comfortable with the least energy used. Similarly, a radiant heater placed near individuals will make them feel comfortable using far less energy than raising the air temperature of the entire room to a comfortable level. I figure, why cool the back seat too when there is nobody back there?

Pretty impressive (to me) that this little wonder of a car can consistently make these trips (over 5000 ft of climbing!!) and keep us comfortable with a "comfortable" range margin too.

Aerowhatt