BrockWI
Posts: 541
Joined: Fri Mar 28, 2014 6:28 am
Delivery Date: 28 Mar 2014
Leaf Number: 423875
Location: Green Bay, WI.
Contact: Website

Re: Eliminate Foggy Windows Without Impacting Range

Sun Jan 15, 2017 10:54 am

I also noticed that sometimes when it was cold and I hit the defrost the A/C light comes on but in leaf spy the power consumed doesn't change, this would imply the compressor isn't actually running even though the light is on. I would guess it is similar to the heater where if it is either cold enough or the "cold side" of the compress is cold enough it just doesn't run. I have a 13 S so it may be different with the heat pump models.
3 kw solar pv - XW6048 - 8 L16's
4 ton GSHP
2003 VW TDI 170k miles - 52 mpg lifetime
evse level 2 - Clipper Creek HSC-40
2013 S model with QC package Mar of 2013

User avatar
IssacZachary
Forum Supporter
Posts: 532
Joined: Fri Jan 13, 2017 9:57 am
Delivery Date: 15 Nov 2016
Leaf Number: 420789
Location: Gunnison, CO, USA

Re: Eliminate Foggy Windows Without Impacting Range

Sun Jan 15, 2017 2:59 pm

jjeff wrote:No I realize the light comes on, but did the compressor? You might not be able to hear it from inside the car but whenever I've pushed the A/C button in extreme cold the light comes on but if you go outside the car you'll notice the condenser fan isn't running, and I'd assume by this that the actual compressor is also not running but I'm not positive.


Interesting. Do you know if in a heat pump heated Leaf if it is the same compressor for both heat and A/C? I wonder if it uses one compressor to both cool and heat the defrost air, but probably with aid of the resistance heater of course. Maybe the compressor just stops working all together at a certain sub-zero temperature?

It definitely doesn't make any sense to cool freezing air. It would frost up the evaporator. So then the evaporator would need heat to be defrosted. But then there'd be no effect on dehumidifying the air. Only when the air temp is above freezing does it make sense to turn on the A/C to dehumidify the air.

I suppose Nissan knows this and built their vehicles accordingly. But the fact that they left the A/C light to come on anyways is confusing. :?
2013 SL 45,000 miles.
12 bars until 44,300 miles on June 2, 2017. :D
11 bars current. :)
The Nissan Leaf is the fourth best long distance car for highway driving. >>Best Long Distance Cars<<

gregn
Posts: 81
Joined: Wed Apr 06, 2016 8:29 pm
Delivery Date: 06 Apr 2016
Leaf Number: 308289
Location: Montpelier, VT

Re: Eliminate Foggy Windows Without Impacting Range

Tue Jan 17, 2017 8:49 pm

I found this ,
There is a guy in the UK that uses this stuff. He has been running a video account of his experience leasing a leaf in the rural uk. Rural Leaf on youtube. It works and that has to one of the wetter spots on the planet. I've seen the evidence of it working over a few years of these video logs. I haven't used it personally but haven't had too much issue with fogging. My trips are short enough and I have the 2016 SV so heater use isn't too bad.

Fog Doc.
Here is the website.
http://fogdoc.com
2016 Leaf SV Pearl Blue
67 mile daily commute
Bat Stats@15%SOC: AHr=78.23 SOH=98% Hx=93.13% Balance Delta = 15mv
odo=16,820

LeftieBiker
Posts: 6953
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 31 May 2013
Location: Upstate New York, US

Re: Eliminate Foggy Windows Without Impacting Range

Thu Jan 19, 2017 3:23 am

The idea that recirculation and defogging are antithetical modes is not always correct. When the air outside the car is saturated with moisture - as in heavy rain for fog - the combination of A/C and recirculate (with heat as well, if the ambient temps allow) will dry the air out faster and keep it drier. The reason is that the air inside the car quickly becomes drier than the air outside; bring in a constant stream of wet air makes less sense than recirculating drier air, while continuing to remove more and more moisture from it. This was easy to prove in older cars with manually operated recirculate doors and separate A/C buttons, and I did so all the time. It's tempting to assume that the car manufacturers are idiots for not allowing this, but the more likely explanation is that they are practicing CYA when locking out recirculation in defrost/defog mode. Since there are many situations in which it is better to have the fresh air intake open, they make it mandatory.

Of course, once I discovered that the floor only setting will also allow some air to escape from the defroster vents, I was able to use 'partial recirculate' to make it more effective in damp weather by using A/C + Floor only. The only drawback is cold feet, and that can be solved by adding heat to the mix.
2013 "Brilliant Silver" SV with Premium Package and no QC, and 2009 Vectrix VX-1 with 18 Leaf cells.

The most offensive, tasteless phrase in use here is "Pulled the trigger." I no longer respond to posts that use it.

gshepherd
Forum Supporter
Posts: 175
Joined: Wed Apr 27, 2016 12:01 am
Delivery Date: 03 Jun 2016
Location: Seattle / Phoenix

Re: Eliminate Foggy Windows Without Impacting Range

Thu Jan 19, 2017 1:07 pm

To answer the earlier question about the heat pump, there is only one compressor, and it only operates in one direction. There are a set of valves including a three-way valve to redirect the refrigerant between an interior condenser (heat), interior evaporator (cool), and an exterior dual-purpose condenser/evaporator. The upshot is the system can switch between cabin heating and cooling in a reasonable amount of time.

For dehumidification, it runs in cooling mode and adds the resistance heater (PTC) as needed to maintain desired cabin temperature. What is not clear but seems possible in theory is that the system might be able to work like a true dehumidifier and operate both interior condenser and evaporator coils simultaneously, greatly reducing the need to run the PTC element.

A downside to the heat pump is when switching to heating mode: there can be considerable moisture condensation on the evaporator coils, and the condenser coils don't seem to get hot enough to dry the air quickly, so it turns into a cabin humidifier until the evaporator coils dry out. Too bad there wasn't some kind of system drying mode added. It could clear the system of moisture during charging, for example, but would probably require a reversible or second blower to exhaust the moisture outside rather than into the cabin.

It should be noted that many EVs don't have the heat pump. I believe I read that Tesla uses resistance only.
2016 LEAF SV

User avatar
IssacZachary
Forum Supporter
Posts: 532
Joined: Fri Jan 13, 2017 9:57 am
Delivery Date: 15 Nov 2016
Leaf Number: 420789
Location: Gunnison, CO, USA

Re: Eliminate Foggy Windows Without Impacting Range

Wed Feb 15, 2017 1:39 pm

Well, I went and bought a bottle of Rain-X Anti-Fog, and so far I don't see any difference. It actually seems the windows fog up even worse. Yesterday was a terrible day for fogging windows. But then again I really can't tell. Maybe I did something wrong? Maybe it has to cure? I don't know. But at least I used as little as possible so as to not have greasy windows. I also put Rain-X on the outside as soon as I had a day that was 40°F/4°C. But by the time I got the Anti-Fog on inside it was below 32°F/0°C again. Maybe that's what I did wrong.
2013 SL 45,000 miles.
12 bars until 44,300 miles on June 2, 2017. :D
11 bars current. :)
The Nissan Leaf is the fourth best long distance car for highway driving. >>Best Long Distance Cars<<

jjeff
Posts: 1415
Joined: Wed Jan 13, 2016 9:10 am
Delivery Date: 13 Jul 2014
Leaf Number: 422121
Location: MSP MN

Re: Eliminate Foggy Windows Without Impacting Range

Wed Feb 15, 2017 1:53 pm

If your having bad fog problems and you live in a snowy climate I'd suggest using something like Weathertech or rubber floor mats. Snow getting on the carpet and melting really holds the moisture and then when you heat the interior of the car that moisture gets in the air and condenses on the windows.
I was having bad fogging issues when I first got my Leaf and it turned snowy, after I got the Weathertech floor mats(which I think are kind of overpriced but do work) and regularly wet vac them dry of standing water things are much better. It's my belief why ICE vehicles don't fog as bad is because they have so much more heat available that they are actually able to try out the carpet, not so much with a Leaf where heat is a precious commodity.
I don't know about Fog-X but I know with Rain-X your supposed to let the film dry before wiping it off, when I was using it I let it dry over night and wiped it off in the morning and it would probably be best to do this when it was above freezing although I don't know this for a fact.
2012 SL purchased used 2/'16
2013 S w/QC purchased new
Juicebox Premium 60a L1/L2 EVSE, Ebusbar 16a L1/L2 EVSE
'12 EVSEupgrade'd 20a L1/L2 EVSE, '13 EVSEupgrade'd adjustable 6-20a L2, 6-13a L1 EVSE
Zencar 13, 20, 30a L1/L2 portable EVSE
GE Durastation 30a

BrockWI
Posts: 541
Joined: Fri Mar 28, 2014 6:28 am
Delivery Date: 28 Mar 2014
Leaf Number: 423875
Location: Green Bay, WI.
Contact: Website

Re: Eliminate Foggy Windows Without Impacting Range

Wed Feb 15, 2017 2:10 pm

I totally agree that keeping the foot-wells as dry as you can helps a LOT. I also end up shop vacuuming them often sucking up water (melted snow) and if I can I throw a fan in the car overnight to dry everything out in the foot wells.

I also applied it, let it sit overnight and wiped it clean the next day. It takes 2 or 3 clean dry towels to get it clear again, but once it is clear it seems to last about a month, depending on how often it is fighting the fog :)
3 kw solar pv - XW6048 - 8 L16's
4 ton GSHP
2003 VW TDI 170k miles - 52 mpg lifetime
evse level 2 - Clipper Creek HSC-40
2013 S model with QC package Mar of 2013

User avatar
IssacZachary
Forum Supporter
Posts: 532
Joined: Fri Jan 13, 2017 9:57 am
Delivery Date: 15 Nov 2016
Leaf Number: 420789
Location: Gunnison, CO, USA

Re: Eliminate Foggy Windows Without Impacting Range

Thu Feb 16, 2017 4:02 pm

jjeff wrote:If your having bad fog problems and you live in a snowy climate I'd suggest using something like Weathertech or rubber floor mats. Snow getting on the carpet and melting really holds the moisture and then when you heat the interior of the car that moisture gets in the air and condenses on the windows.
I was having bad fogging issues when I first got my Leaf and it turned snowy, after I got the Weathertech floor mats(which I think are kind of overpriced but do work) and regularly wet vac them dry of standing water things are much better. It's my belief why ICE vehicles don't fog as bad is because they have so much more heat available that they are actually able to try out the carpet, not so much with a Leaf where heat is a precious commodity.
I don't know about Fog-X but I know with Rain-X your supposed to let the film dry before wiping it off, when I was using it I let it dry over night and wiped it off in the morning and it would probably be best to do this when it was above freezing although I don't know this for a fact.


My floor mat has been an ice rink for the past month! Literally, I couldn't step in the car without slipping! It's finally melted, so I guess that explains the foggy windows. :lol: I'll try taking the mats out and drying them.
2013 SL 45,000 miles.
12 bars until 44,300 miles on June 2, 2017. :D
11 bars current. :)
The Nissan Leaf is the fourth best long distance car for highway driving. >>Best Long Distance Cars<<

SageBrush
Posts: 1223
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: Eliminate Foggy Windows Without Impacting Range

Thu Feb 16, 2017 4:42 pm

LeftieBiker wrote:The idea that recirculation and defogging are antithetical modes is not always correct. When the air outside the car is saturated with moisture - as in heavy rain for fog - the combination of A/C and recirculate (with heat as well, if the ambient temps allow) will dry the air out faster and keep it drier. The reason is that the air inside the car quickly becomes drier than the air outside; bring in a constant stream of wet air makes less sense than recirculating drier air, while continuing to remove more and more moisture from it. This was easy to prove in older cars with manually operated recirculate doors and separate A/C buttons, and I did so all the time. It's tempting to assume that the car manufacturers are idiots for not allowing this, but the more likely explanation is that they are practicing CYA when locking out recirculation in defrost/defog mode. Since there are many situations in which it is better to have the fresh air intake open, they make it mandatory.

Of course, once I discovered that the floor only setting will also allow some air to escape from the defroster vents, I was able to use 'partial recirculate' to make it more effective in damp weather by using A/C + Floor only. The only drawback is cold feet, and that can be solved by adding heat to the mix.

The problem with recirc mode is that you will accumulate in the cabin the moisture from breathing.

Since I am cold tolerant, I think the best solution is application of a hygroscopic layer to the glass, e.g. Fog Doc as mentioned above. I just have to convince myself that the water droplets have somewhere to go.
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

Return to “Tips & Tricks”