meier
Posts: 34
Joined: Tue Aug 16, 2016 5:30 am
Location: Denmark / EU

Anyone ever figured out how the Heating controls work ?

Thu Jan 25, 2018 4:53 pm

OK -

So there is a knob for the Heating power / Vent power /

So i set the heating on full MAX - The Ventilation on full .... Will the cooleant temperature drop if i reduce the setting on the heater knob ??
or is it a fixed temperature - and the position only have to do with "auto" setting.

If i select a fixed setting on the heater knob and also on the vent - and change the setting from outside car air to inside car air -
the range seems to be the same - should it not differ ?? i mean heating up air from the cabin already maby 15c insted of outside air maby 0c ??


Last question : The Auto setting on the ventilation duct selector - what does it do ?? I thougt it would swap around windshield, front, boot ect - but seems its stuck in windshield/boot ... ??

The more i drive this car the more i love it - 2 years 30000km - no problems :-)
c-zero - 2011 - 35000km

bradleydavidgood777
Posts: 178
Joined: Tue Aug 29, 2017 11:55 am
Location: Media, PA

Re: Anyone ever figured out how the Heating controls work ?

Wed Jan 31, 2018 8:35 am

If you change the temperature control knob, yes the coolant temperature will change. And this does not only have to do with the auto setting.

The setting of the temperature control knob should affect the range the same regardless of the setting of outside vs inside air because you are using the same amount of energy in both situations. In other words, you are not setting a "desired temperature" in which the car tries to match, you are setting the level of the coolant. So the only difference is that it will take much longer to heat the air in the car if you have outside air on.

While waiting at the dealer for a new airbag/recall, I read thru the entire manual. The rules for how the auto setting are in there. I can't remember the details. But I do remember that most of the time, the auto setting would result in what you are describing, air going to the windshield and to the floor. After reading it, I decided that I would never want to use the auto setting.

For heat I like the setting for dash vents and floor combo. Seems to heat the car the quickest.

Except when I need the windshield or the side windows cleared of frost or condensation, then I turn it on windshield/floor combo.

Then I adjust the temperature knob and the fan speed knob to stay comfortable but not too high so that I save energy.

So depends on the day and whats going on with the windshield and windows. Could never trust the auto setting to figure that out. Another "great idea" to make life "easier" that I don't think really helps at all. In fact, I think it makes it harder because you think it might be easier, but don't know the rules its using and it doesn't make sense most of the time anyway. Then you are stuck with another setting on your dial that you have to watch you don't land on. And its easy to land on that setting instead of "Off", if you are looking to go to off. And you have to take your eyes off the road too long to see where you are...so dangerous too.
2017 I-Miev

ChrisEV
Posts: 55
Joined: Tue Nov 14, 2017 3:47 pm
Location: GTA, Canada

Re: Anyone ever figured out how the Heating controls work ?

Mon Feb 05, 2018 5:40 am

meier wrote:OK -

So there is a knob for the Heating power / Vent power /

So i set the heating on full MAX - The Ventilation on full .... Will the cooleant temperature drop if i reduce the setting on the heater knob ??
or is it a fixed temperature - and the position only have to do with "auto" setting.

If i select a fixed setting on the heater knob and also on the vent - and change the setting from outside car air to inside car air -
the range seems to be the same - should it not differ ?? i mean heating up air from the cabin already maby 15c insted of outside air maby 0c ??


Changing the temperature knob does change how much power the heater uses. I’ve finally gotten Cani0n working and the last few days I’ve seen the heater draw anywhere from 1.5-5.5 kW depending on what it’s set. You can sort of see this when you’re idling at a stop light where the power gauge is at. You can actually see the amount of power consumed fluctuate up and down as it tries to maintain a set temperature.

RR indicator doesn’t automatically adjust for different temperature settings but you’ll lose bars slower with a lower temp setting vs. a higher setting.
2012 i-MIEV SE Premium

meier
Posts: 34
Joined: Tue Aug 16, 2016 5:30 am
Location: Denmark / EU

Re: Anyone ever figured out how the Heating controls work ?

Tue Feb 06, 2018 2:19 pm

So - if you start the car, idle - turn on heater and fan on lowest setting - I assume heater will draw full 5kw until temperature of cooleant is reached - then if you turn up the heater to MAX does the power consumption rise again ...

I have decide trying to measure the coelant temperature - that for sure will tell - ill be back with results ( I still think the temperature is static )


Did you figure out about the auto setting on the airflow/airoutput selector ? its so weird
c-zero - 2011 - 35000km

siai47
Posts: 360
Joined: Fri Jun 14, 2013 5:54 pm

Re: Anyone ever figured out how the Heating controls work ?

Thu Feb 08, 2018 7:54 pm

Everything you never wanted to know about your heater.

http://www.mhi.co.jp/technology/review/ ... 474019.pdf

Pretty neat water heater. It appears it is designed to operate with eight different power levels as each of the four heating elements are of different sizes. It is a PTC heater so each element heats to the same temperature and controller just selects which size and number of elements are in use. The interior unit has a "blend" door that directs incoming air either through the heater core or bypasses it (as in a conventional car). The water heater has temperature thermocouples mounted to check the water temperature at the heater inlet and tries to maintain a preset temperature. So the water temp remains constant (like a conventional car) and the interior air temp is controlled by the blend door. :)

Aerowhatt
Gold Member
Posts: 426
Joined: Wed Jan 28, 2015 1:52 pm

Re: Anyone ever figured out how the Heating controls work ?

Sat Feb 10, 2018 7:49 pm

I stumbled across this updated version of the technical review of the heating unit:

https://www.mhi.com/company/technology/ ... -2-57.html

Perhaps this (below) copied from another thread will help with using the heater efficiently;

Doing hiking trips to the mountains for two full winters (this is the third) has helped me find the best most efficient way to use the stock heat. It makes sense when you think about it and is different than we are conditioned to use the heat from years of ICE driving.

1. Preheat the car if you can.
2. Use the seat heater. I usually turn it off after ~10 minutes because it gets too hot
3. Direct the heat to the floor only, on recirculate (it will keep all of you warm, heat rises). One notch toward defrost if needed to prevent fogging.
4. Start driving with the fan on high (I like the setting just below high because it is a bit quieter)
5. Temperature setting should be where ever you need it to be. I generally start high and end up on the second or third position up from the green dot.
6. If and when the heat is adequate inside the car turn the temperature down, not the fan!

#6 is critical! The heated fluid goes from the heating element right into the cabin. The more heat that you take out of that fluid before it makes the long trip outside of the cabin (under the hood etc.) the less heat is wasted to the cold environment. Also the lower the setting on the temperature knob the lower the resulting temperature of the fluid loop. So if one reduces the temperature setting instead of the fan speed the water loop is not heated as hot and less energy is wasted in the plumbing loop. For instance with the temperature knob set to the first position above the green dot. The system will keep the fluid around 110 F. At the highest temperature setting on the knob the fluid will heat to around 190 F. The MAX button overrides the heat setting on the heat knob and heats the fluid to around 190F until it is turned off.

So back to my test run. I drove around town town for 1.5 hrs using the Canion heater power graph to average my power consumption for heating. The average for the trip was 638 watts/hr. That (generously) equates to about 3 to 4 miles of worth of lost driving power (per hour) for staying comfortable. I know from previous non preheat trips at around 33 F that approximately an extra 800 watts of power is required to warm the car up inside (just the front, heat directed to floor only using the “max” button until the the chill retreats). Which yields ~1500 watts for the first hour starting out cold (up to ten miles worth of range used for heat in the first hour).

The 2014’s have a styrofoam piece under the front carpeting. I don’t think the 2012’s have this and it would make a difference, I’m sure. But overall, if one optimizes usage of the heating built into the car and it isn’t to to cold (29F is reasonably cold though). It doesn't take away all that much mileage to stay comfortable if best practices are employed.

Aerowhatt
2014 cool silver ES, acquired new 4/2015 (42.7ah at ~26K miles)
2014 Labrador Black Pearl ES, acquired new 3/2016 (41.5ah at ~15k miles)

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