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Climate control confusion. Range projected drops when fan on

Posted: Sun Apr 28, 2013 8:51 pm
by 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. :o
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. :o :)

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?


Re: Climate control confusion. Range projected drops when fa

Posted: Sun Apr 28, 2013 9:35 pm
by 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.

Re: Climate control confusion. Range projected drops when fa

Posted: Mon Apr 29, 2013 4:34 am
by 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 :(

Re: Climate control confusion. Range projected drops when fa

Posted: Mon Apr 29, 2013 8:54 am
by 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.

Re: Climate control confusion. Range projected drops when fa

Posted: Mon Apr 29, 2013 10:01 am
by 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. :|

Re: Climate control confusion. Range projected drops when fa

Posted: Mon Apr 29, 2013 10:52 am
by 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


Re: Climate control confusion. Range projected drops when fa

Posted: Mon Apr 29, 2013 2:17 pm
by 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. :oops:
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!


Re: Climate control confusion. Range projected drops when fa

Posted: Mon Apr 29, 2013 9:01 pm
by 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).

Re: Climate control confusion. Range projected drops when fa

Posted: Thu May 02, 2013 10:52 am
by iDriver

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!)

Re: Climate control confusion. Range projected drops when fa

Posted: Tue Jul 16, 2013 1:42 pm
by 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.