Climate control confusion. Range projected drops when fan on

[acensor]

Newbie (as some of you know... three weeks and 200 miles. SE)
finding climate controls/behaviours confusing.

We were out today in balmy weather...about 65 F outside, but with the sun pouring in though EV's generous windows, starting to heat up inside. Wanted to get some outside air in without "opening the windows.
Before trying to turn on fan these were the setting from top control 99% sure
(I almost never say 100% when going by memory):
Top (the "Push Max" dial)
Set to the green dot at the 9 oclock position
Middle ("Push A/C") set to "off".
Bottom (directs vents to face, feet, etc) Set to feet and face.
NO lights on any dial.

===========
Turned the middle dial with fan icon on it clockwise .
Fan began operating. Fine.
But estimated remaining range (ERR) dramatically dropped from about 36 miles to 30.
Turned fan back off, and ERR rapidly came back up.
Turned fan setting to auto and ERR dropped again.
Don't think AC was on (as no light on middle dial, and no obvious cold air coming out.)
(Admit I didn't leave it on long enough to see if cooling compressor was running, as wife was worried seeing estimated range dropping rapidly. But isn't AC on only if light is on in the A/C dial?)

I believe I was paying detailed attention to what I was doing as wife was driving and I was specifically and only working on operating the fan controls.

Got home and parked in the garage played with the controls and was able to get anything from mild to robust ventilation fan speeds (by pressing in upper "MAX" dial with it's light going on got a really stiff breeze going) without seeing estimated range plunge down.

Any ideas what I was/am doing. Or more specifically, exactly what steps/setting I should do (and not do) to get the circulation fan going without heating or air-conditioning kicking in?

Alex

 

[Vike]

Hmm - interesting. First off, MAX is for maximum heating or cooling - you don't use it otherwise, and you'd rarely use it for long (especially the heater). If you didn't have the A/C on, I'm assuming it would maximize heat. The interesting part is that you had the temperature set to neutral green, which should run neither heat nor A/C, and in that context, MAX should be meaningless, since it doesn't "boost" the fan itself (i.e., you'd get the same fan behavior by just turning the fan speed all the way up). Basically, those settings just didn't make any sense.

So what does the i-MiEV think of this? As I said above, MAX w/o A/C does mean MAX Heat, so perhaps you just confused the RR calculator, which "thought" the heat was on full blast even though your temperature setting disabled it. Since I thought the RR calculator was looking at actual power draws rather than control settings, that seems unlikely, but one never knows.

But I'm afraid "confused RR calculator" is the best I can manage. Anyone else have theories? In particular, anyone have an idea what hitting MAX does when temp is on the green dot? I'll admit I've never tried it, and my vehicle and manual are not immediately accessible to me this evening.

 

[JoeS]

RR takes roughly a 20% hit when the heater is enabled (also depends on the setting) and i don't remember how much of a hit when aircon is turned on. It's a percentage of RR and not an absolute number.
The good news is that it appears to NOT store this information and if you subsequently turn off the climate control the RR predictions will be based only on what had been consumed by the vehicle without anticipating that you will continue to use climate control.
acensor, you might carefully study the manual as, just like with the Remote, it takes some getting used to

 

[Vike]

After pondering this a bit, I re-read the post and see I might have misinterpreted it - I'm thinking now that acensor was just describing the top rotary dial control (personally, I just call the controls "temperature", "fan speed", and "air direction"), and was not saying that MAX was on.

So put aside my blatherings on that point, though I'm still curious about pressing MAX with the temperature on the green dot (I'll try it when I'm back in the car this evening).

And to answer acensor's direct question (in case that got lost in the fog of words in my earlier reply), you get fan only (no heat or A/C) exactly as you were, I believe - just put temperature on the green dot, and the fan speed to whatever level you prefer. No heat, no cooling.

A general observation on HVAC - heat is a pretty terrible power draw, but I've more or less stopped worrying about A/C, much less the fan. A/C does have an effect on range, but pretty tiny compared to the heater, and rarely enough to affect my travel plans. It's fun to fiddle with and observe various range-affecting behaviors, but one can make oneself crazy with this stuff, and I try to remind myself to just enjoy EV driving.

 

[aarond12]

Did you happen to have the bottom control dial on Defrost? That would automatically engage the A/C... That's the best I can come up with. Then again, I never display the RR. It's no better, in my mind, than the charge gauge. :|

 

[Don]

As Vike mentioned, in a 'fan only' situation, the 'MAX' button does nothing for you . . . . except evidently reduce the RR number and that's probably because it was also engaging the heater

Leave the MAX button alone and you'll find the fan operation doesn't affect the RR number

Don

 

[acensor]

Thanks all.

You know, thinking back, what I may have done is accidentally take the top dial off the green "neither heat nor cool" 9-O'clock position and put it into heat mode.
I which case it was heating (and that explains the drop in estimated range)... even though I didn't notice it as it takes a while for the heat to start pouring out of the vents.

So guess can take that as a bit of learning ..... "See estimated range dropping quickly (when neither hill climbing, drag racing, nor passing traffic on the freeway, better check if someone's turned on the heater."

Nice to hear that AC can be used moderately without as drastic drainage.

Thanks all!

Alex

 

[Vike]

Just to report the results of satisfying my own curiosity - clicking on MAX with the temperature control in the neutral position just puts on the fan full blast. I sat there like that for a couple of minutes, and it didn't heat up, so I guess that's all it does. Had no effect at all on reported RR - so yes, acensor, you probably did click it up to heat (it only takes one notch - MAX goes full blast regardless of what level of heat you have set).

 

[iDriver]

acensor-

I frequently use the "MAX" with Green Dot button selected and No A/C turned on. It doesn't seem to effect my RR at all. It's actually kind of nice to fire it up when I first get in the car, just to flush some of the hot air out.

Even when i'm using the A/C it doesn't effect my RR very much. Honestly, the A/C in this car is one of the best features. It get's cold FAST and RR is just fine. (Well, unless i'm using the AC with MAX turned on, then the RR does notice it a bit more, but nothing like the heater!)

 

[RobbW]

The two or three times I have turned on the A/C, I noticed an immediate ~10 mile drop in my RR gauge. This was with the top temp dial set to cold, the other two dials set to "Auto", and the A/C button pushed on. The drop in RR was so dramatic each time that I nearly immediately turned the A/C off, except once yesterday when it was 91° out and raining. So, I had to leave the A/C on for a bit until the showers passed. I am now VERY hesitant to use the climate control (CC) and will drive with the A/C off and windows open even in 90°+ temps. The heat doesn't bother me too much. I prefer the outside air anyway. The only time not using the A/C becomes a problem is when the wife and kids are riding along.

So, I have a question about the use of CC and any drop in RR. Is this immediate drop in RR pretty much the only alarming thing I should see? Is the i-MiEV somehow calculating the estimated reduction in range and taking the number right off the top? Or will I see both that immediate drop in range AND an exponentially greater decrease in my range as I continue to drive and use the CC?

If the answer is just that initial drop in RR, then I will feel more comfortable using the CC when necessary. However, if I'm going to see that immediate drop PLUS my remaining range is going to tick down twice as fast as I continue to use CC, then I will avoid using it whenever I can.

 

[jray3]

The two or three times I have turned on the A/C, I noticed an immediate ~10 mile drop in my RR gauge.
So, I have a question about the use of CC and any drop in RR. Is this immediate drop in RR pretty much the only alarming thing I should see? Is the i-MiEV somehow calculating the estimated reduction in range and taking the number right off the top? Or will I see both that immediate drop in range AND an exponentially greater decrease in my range as I continue to drive and use the CC?

Robb, your 10 mile RR redux is exactly what most of us have seen, it will stick, and I'll say you won't see further penalties. I'm using air conditioning or heat unless I need to go farther than about 45 miles.

 

[acensor]

Hi Robb.

You wrote, in part---
"So, I have a question about the use of CC and any drop in RR. Is this immediate drop in RR pretty much the only alarming thing I should see? Is the i-MiEV somehow calculating the estimated reduction in range and taking the number right off the top? Or will I see both that immediate drop in range AND an exponentially greater decrease in my range as I continue to drive and use the CC?"

It is my distinct impression that, as you speculate, the RR computer is indeed calculating the estimated reduction in range and taking the number right off the top.
Saying "if you keep driving with the AC (or heat) on based on that and the way you drove the last 15 miles this is how far I think you'll get.
Notice that if you promptly turn the CC back off the RR meter rather promptly restores the estimated range remaining back up the 10 miles it knocked off a few seconds ago.

 

[Don]

Yes, the RR drop is greatest when you turn the A/C on with a full charge because it's computing the total range lost for the full trip - As far as it predicts the charge can take you. If you did the same thing with the battery half charged, the RR drop would be half of the 10 miles you saw

How far you have the temp dial set into the A/C range, and how fast you have the fan blowing affects how much RR is lost - Less of either will give a lower drop. In my experience, I believe the car's thermometer is taken into the equation as well. You'll see a bigger RR drop on a 95 degree day than on an 85 degree day

If the loss of range running the A/C in the summertime shocks you, just wait until WINTER when you switch on what passes for a heater - The RR drop will be more than triple . . . . and you still won't be comfortably warm. Preheat the car before you leave everyday for sure!

Don

 

[BillThompsonMIEV]

My experience is that use of A/C causes a 12-15% reduction in RR.

 

[BenBrown]

I've wondered about climate controls and am looking forward to trying them out beyond my test run of an i-miev... in the next couple of weeks.

With the Leaf, I've discovered I can turn off the heat/or a/c and simply use the fan to clear away any fogging with absolute minimal draw to the battery. Has anyone else found the same technique can be used on an i-miev? I'm dressed for the outside weather when I get in the car anyway. The seat heating and heated steering wheel in the Leaf normally makes it comfortable enough. The main challenge is keeping the windshield clear, which, simply periodically turning on the fan w/no heat or cold seems to meet my needs and prolong the range. It would be SO good if I can do this in the i-miev.

 

[fjpod]

I often do it. With no heat or a/c, it preserves your range.

 

[PV1]

A pair of Thinsulate gloves, a heavy coat, heated seat, and the fan on one click if needed is how I roll. Lately though, I've been experimenting with having the heat on one click. This heats the liquid to around 85 F. Once the loop is up to temperature, the heater pulls around 1,000 watts, which is less than a bar for a drive less then 30 minutes.

I've also been looking at splicing the motor coolant and heater loops together to warm incoming air to at least 50 F, depending on terrain and speed. Highway heats the coolant the most, but a hilly route around 40 mph works too. Power shutters blocking air from passing through the radiator are needed though, and needed to regulate coolant temperature.

The controls for the climate control in the i-MiEV are great. They allow for full manual control of the system. The only automated function is when going to full defroster, the system activates AC and draws fresh air, but both are easily overridden and the settings stay until air is directed away from the windshield, regardless of fan speed and temperature setting. Air can be directed anywhere even when the fan is off.

 

[iwatson]

The imiev is my wife's car. She and I apparently drive very differently.

Most all her trips are short and thus the i's computer realizes that she has a low average speed. When she turns on the heat it has a big effect on the RR meter. In other words, the car figures that she will be driving at a low average speed, but with heat going which is a big draw against available energy.

On the hand when I drive her car I travel further distances, which means a higher average speed. Even though we all know that as you drive faster the car consumes more energy than slower, when stopped the car consumes little if any energy (just enough to keep the brake lights on). So you could park the car turned on without any accessories on and sit for a long time with no reduction in range. But when you turn the heater on under the same circumstances RR would continue to decline down to nothing (Zero) without ever going anywhere.

So my point is...as an example we went to dinner a few nights ago and used the heater. When we started out we had a RR estimate of 48 miles. When I turned the heater on it changed to 34 miles. I was driving the car, but my wife had been the sole driver for the last few days. after traveling about 5 miles with the heater on, I looked down and the RR meter had adjusted to my driving and was now reading 37 miles. We went another 4 miles to the restaurant and upon arrival the meter still read the same 37 miles.

So the imev's computer uses average speed to determine the heater's effect on range. The faster you go with the heater on the more range you'll get. The slower or stopped vehicle will use range more quickly because the heater is a constant energy draw, regardless of vehicle speed.

 

[JoeS]

...as an example we went to dinner a few nights ago and used the heater. When we started out we had a RR estimate of 48 miles. When I turned the heater on it changed to 34 miles. I was driving the car, but my wife had been the sole driver for the last few days. after traveling about 5 miles with the heater on, I looked down and the RR meter had adjusted to my driving and was now reading 37 miles. We went another 4 miles to the restaurant and upon arrival the meter still read the same 37 miles.

iwatson, you've presented an interesting supposition. Traditionally, I would expect to see the RR plummet after driving a while at increased speed and I wouldn't expect the RR algorithm to do anything other than take a percentage off the RR as a function of heater energy consumption. In the example you used, I would have attributed the range increase due to the heater turning off or reducing its current draw after it had warmed up the fluid.

 

[PV1]

I find that interesting, as well, but not really surprising.

Measuring the consumption of my heater at different settings, the heater runs at full power until the loop is at temperature, at that point, it only uses as much as necessary to maintain temperature. With the car stationary with 20 F ambient and the heater at 1 click into the red and fan at full speed, the heater jumps between 1,000 watts and 0. If I turn the temperature up a click, it'll use 2,000 watts until up to temperature, then drop back down. Turning the temperature down, it'll run for a few minutes and not pull anything, though the pump is still running. Turning the top knob to the green dot results in an increase in RR and an immediate drop in temperature of the air coming out of the vents since the pump shuts off. Click it back into the red, and the heat comes right back since the pump turns on.

It seems that the car does an immediate RR reduction, then continues calculating RR based on car and heater usage.