Eliminate Foggy Windows Without Impacting Range

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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.
 
jjeff said:
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. :?
 
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
 
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.
 
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.
 
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.
 
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.
 
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 :)
 
jjeff said:
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.
 
LeftieBiker said:
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.
 
SageBrush said:
I just have to convince myself that the water droplets have somewhere to go.

It seems the Rain-X AntiFog is working. Maybe it had to cure. I still get some fog and frost, but I notice that there's now considerably more on the rear window, which I didn't treat with AntiFog. But there is one thing I do get. Water droplets on the inside of the windshield. These leave little water spot marks when they dry.
 
IssacZachary said:
SageBrush said:
I just have to convince myself that the water droplets have somewhere to go.

It seems the Rain-X AntiFog is working. Maybe it had to cure. I still get some fog and frost, but I notice that there's now considerably more on the rear window, which I didn't treat with AntiFog. But there is one thing I do get. Water droplets on the inside of the windshield. These leave little water spot marks when they dry.
Interesting -- so the droplets are not heavy enough to fall down the glass.

This water is distilled (evaporated) so it might suggest that the spot you are seeing is from collection of dirt on the glass that is collected by the condensate. Perhaps a glass cleaning once a week will help.
 
On the side windows, yes the droplets run down the glass. On the windshield the angle must affect the way the gravity pulls on the droplets. If there's enough moisture the droplets collect and run down the windshield. A quick buffing gets the water marks off. Maybe that's what's helping the AntiFog do its thing, maybe I hadn't buffed enough.
 
jjeff said:
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.
As soon as I could get the floor mats off of the floor (they were frozen at first) and hung them up to dry I noticed a big improvement! Thanks!

I wonder if there'd be any merit in fabricating some heated floor mats.
 
IssacZachary said:
jjeff said:
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.
As soon as I could get the floor mats off of the floor (they were frozen at first) and hung them up to dry I noticed a big improvement! Thanks!

I wonder if there'd be any merit in fabricating some heated floor mats.
The thing is you wouldn't want it on when driving as that would evaporate the moisture in the air, which would in turn condense on the cold windows. No personally I think the best thing is to suck up the water while it's liquid and not let it soak into something like the carpets where it would be much harder to remove. I also took out my Weathertech mats yesterday(60F and sunny, in Feb in MN :shock: now thats wrong!) anyway the carpet was basically dry underneath, was happy to see that.
 
So far this year with RainX inside and out I notice that for the most part both inside and out the windows tend to fog less than other cars, with the exception of the inside of the windshield itself. That seems to fog more actually. I wonder if I reapply RainX interior Anti-Fog to the inside of the windshield it will help. :?:
 
I live in an area where it stays below freezing for about 4 months. The air outside the car is very dry, and you can get a sore throat breathing it. So you want the cabin to be much more humid. But... if the cabin gets too humid, you get fogging. On my previous car (ICE), I'd adjust the intake/recirculate slider to a position where it was sucking-in just enough dry air to keep from fogging.

Unfortunately, the Leaf seems to have an "all or nothing" approach: either you use 100% recirculate (and get fogging within a few minutes), or you use 100% outside air. Lately, I've been alternating recirc/intake/recirc/intake, about every 4 minutes. Not a good solution (unless someone wants to build a timer circuit, with a slider or knob to set the duty cycle).

I was considering putting the heater on recirculate, but also cracking-open a rear window a quarter inch. I'll try the RainX or FogDoc, but I've never heard of anybody who can just recirculate cabin air below 20F (and we already hit 12F, on November 9th).
 
There IS a partial Recirculate mode, and while it won't work in any of the defrost modes, it WILL work with the vent set to Floor and the fan on 2 or higher, because some air goes out the windshield vents in that mode. With Recirculate on, press and hold the Recirculate button for 2 seconds. The moment the light starts to flash, release it. If it flashes twice and goes out, with no message on the screen, you are in "auto" or "partial" recirc mode. If it displays "Fresh Air" at the bottom of the LCD screen, try again.
 
I find that even when the Leaf lets me use both defrost and recirculation together (which happens at around 30 below zero) I always end up turning recirculation off. Also turning on the heater or defroster to it's lowest settings and leaving recirculation off or partially off seems to do a fine job of keeping the windshield clean and doesn't seem to use any more energy or cause any less confort than turning recirculation on at such low settings. My conclusion is that Nissan knew what they were doing when they designed the 2013 and later model year Leafs and that if they had left us the option to use recirculation and defrost at the same time whenever we wanted we'd use more energy trying to raise the glass temperatures above the dew point inside the vehicle than to draw in some drier outside air and therefore we'd end up turning recirculation off anyway.

So when I'm trying to save energy for whatever reason I just use the lowest heater or defroster settings without recirculation or I turn them off when I can see. But most of the time I try to keep passengers and myself happy by simply hitting the "auto" button or the defrost button and letting the Leaf do it's thing. There doesn't seem to be any happy medium. Either I make everyone freeze or I end up turning the heater up to what it would be if I had the "auto" setting on anyway, although I do usually use a lower temperature setting of 60 or 65 degrees during the winter.

I've tried Rain-X Anti-Fog and am not convinced. It seems to have made the front windshield fog more, until I tried cleaning it off. Now it fogs about normal. I'm not sure what I did wrong, maybe used to much, because the other windows seem to have benefited from the Anti-Fog.

Preheating the car seems to be the biggest solution to fogging problems. Preheat the car off of your EVSE power and then set the heater to whatever you want or even use no heater at all. I can go several miles heat-less this way.

Also during rainy or snowy weather take your mats out and hang them up dry overnight inside your home (as long as they aren't frozen to the floor. I'm thinking of getting some sort of heat pads to put under my mats to get them to thaw.) Or get plastic Weather Tech mats and dump them out when they get water in them. The more moisture you can keep out of the car the better. Maybe use a good rain coat or umbrella to keep yourself drier as well. Keep a dry coat in your car for after skiing and put the wet one in a plastic bag.
 
In a pinch, you can make antifog from detergent. A few weeks ago, I put a TINY smear of Dawn on a damp paper towel and rubbed that on the inside of the windows. Then I kinda polished it off with a dry paper towel. The second step may not have been necessary, but it looked like I might have laid it on too thick. Maybe I should have let it dry first to see. You don't want enough detergent to make it look streaky when it dries, but enough to provide a surfactant to flatten the tiny droplets that cause the fogging.

It worked fairly well. After I run the climate control timer for preheat, the areas I didn't treat are very foggy, and the treated areas are barely foggy. Half a minute of defroster use after starting the car and all is well.

Didn't read all four pages, so sorry if this is redundant.
 
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