nikwax
Well-known member
i had an insect nest in a condensate drain line, so that's another possibility.
Extreme Condensation Issues - Interior of Windshield
- Thread starter amphibious
- Start date
Help Support Chevy Spark EV Forum:
I'll list where I'm at right now after talking with the dealer. Nothing is physically wrong with the car. Some answers and some remaining wonderings.
One should avoid using the AC system for defrosting the windshield/cabin because, while it "dehumidifies" really well, current AC evaporator designs can "hold" a lot of water before the condensed water starts to drip into the drain tube. Just google "condensation" to see what I mean. There's some more optimization that can be done in this space though...
So if you choose or unknowingly use the AC, all that water is still sitting there in your dash. In my and <I think> amphibious' case, we stopped at work or at home and let it sit. It will evaporate somewhat and tend to condense on the windshield on a cold night. This is maybe due to the proximity to the evaporation, but I think it's partially because the windshield has an angle and the other windows on the Spark are vertical. I have noticed that the windshield condensation generally doesn't occur in the region covered by the windshield wiper, telling me that the temperature transfer is helped with dew.
How to get rid of the contained moisture? Pulling in less humid air from outside will do the trick (and is what GM assumes generally), but on a day like today in Portland where it's raining and 95% humidity all day ... it appears you have 2 options:
* If you're driving, don't try... just keep the cabin cold so that condensation doesn't happen.
* If not driving, turn up the heat and recirc to absorb as much moisture as possible (lots of internal fogging if outside is cool) and then crack windows to let it out.
Not sure why I don't notice the overnight windshield condensation on gasoline cars as much yet. Possible suspect is residual engine heat, of course...
Hope this helps!
EDIT: amphibious, if this fixes your issue, can you edit your top post to include a summary and a link to this post so people can find it a little easier? Thanks!
One should avoid using the AC system for defrosting the windshield/cabin because, while it "dehumidifies" really well, current AC evaporator designs can "hold" a lot of water before the condensed water starts to drip into the drain tube. Just google "condensation" to see what I mean. There's some more optimization that can be done in this space though...
So if you choose or unknowingly use the AC, all that water is still sitting there in your dash. In my and <I think> amphibious' case, we stopped at work or at home and let it sit. It will evaporate somewhat and tend to condense on the windshield on a cold night. This is maybe due to the proximity to the evaporation, but I think it's partially because the windshield has an angle and the other windows on the Spark are vertical. I have noticed that the windshield condensation generally doesn't occur in the region covered by the windshield wiper, telling me that the temperature transfer is helped with dew.
How to get rid of the contained moisture? Pulling in less humid air from outside will do the trick (and is what GM assumes generally), but on a day like today in Portland where it's raining and 95% humidity all day ... it appears you have 2 options:
* If you're driving, don't try... just keep the cabin cold so that condensation doesn't happen.
* If not driving, turn up the heat and recirc to absorb as much moisture as possible (lots of internal fogging if outside is cool) and then crack windows to let it out.
Not sure why I don't notice the overnight windshield condensation on gasoline cars as much yet. Possible suspect is residual engine heat, of course...
Hope this helps!
EDIT: amphibious, if this fixes your issue, can you edit your top post to include a summary and a link to this post so people can find it a little easier? Thanks!
This sounds like a totally reasonable and technical reason for this problem. 95% all day?!? Wow,, try to remember the sun shiny days... You get some of those, right?nhergert said:
You want that AC evaporator to be dry overnight. You may want to avoid using the AC for defogging, if possible.
Another fix may be running the fan on high/outside air to try to dry the evaporator, once the car is parked at home, plugged in and done for the day. Set a timer to go back to shut down the car in ? 1hr. ?
Of course if it's still 95%,, who knows....
Once the evaporator is dry, does using the "feet/windshield" position keep the AC compressor off? It's more energy consuming to defog with heat than with AC de-humidification, but if you have this problem, this may be a work around.
(I know pressing the "Defrost" button always turns on the AC compressor and after awhile at a DCFC, even in mild temps, the AC will kick on sometimes.)
zzzzzzzz
Well-known member
I only get fogging in the mornings, when it's extremely cold or raining. To help combat it, I make sure to do remote climate start on "HI" about 15 minutes before heading out, to make sure the cabin is dry enough. I'll then just cycle it once in a while when the fog does find it's way along the commute. Fresh air in, Temp on, 70 degrees. The commute home I don't have any fogging issues. In Portland also.
SparkE
Well-known member
The answer from the dealer really, *really* sounds like a 'how can we explain it's not our fault' from the dealer. You might want to ask the dealer "how come this other guy who has the same vehicle and lives in the same city has never had this problem?"
@NORTON: Yes, the Defrost button seems to turn on the TEMP button by default when coming from off, but it's my understanding from the user manual that the A/C and Heater is controlled with the TEMP button (page 191 or section 8-1). However, what's interesting is that *some* heat still comes out even though the TEMP button is off, discounting what the manual says.
@EldRitch Interesting. I'll keep looking at it, maybe I have moisture that's coming in from somewhere else too...
@SparkE: Well, a good chunk of this I figured out myself, especially the A/C stuff. The dealer more said "we checked out the car according to what the service manual said", which is about what I'd expect. The engineers at GM hopefully actually know what is happening. Any ideas for asking them directly?
@EldRitch Interesting. I'll keep looking at it, maybe I have moisture that's coming in from somewhere else too...
@SparkE: Well, a good chunk of this I figured out myself, especially the A/C stuff. The dealer more said "we checked out the car according to what the service manual said", which is about what I'd expect. The engineers at GM hopefully actually know what is happening. Any ideas for asking them directly?
SparkE
Well-known member
If the car is still under warranty, MAKE SURE you get multiple, written descriptions of your complaint *in writing* before the warranty expires.
I would simply go back to the dealer and explain that a guy with the same car in the same city doesn't have the problem, and the likely culprit is that the drain from the condensation tank is blocked somehow.
I would simply go back to the dealer and explain that a guy with the same car in the same city doesn't have the problem, and the likely culprit is that the drain from the condensation tank is blocked somehow.
nikwax
Well-known member
Portland driver here as well, I've never seen anything like this, except the time we drove down to Salem last winter with all of the HVAC turned off. Other than that, no. Don't even see much fogging in the morning.
SparkE
Well-known member
So you now have reports from TWO owners of the same vehicle in the same city that don't have the problem.
Tell the dealer that it is obviously a problem with YOUR vehicle, and that it needs to be fixed (under warranty).
Tell the dealer that it is obviously a problem with YOUR vehicle, and that it needs to be fixed (under warranty).
I think this issue can be solved in 5 seconds, by pressing one button.
As I understand it, the OP drives with the climate control off, except when he turns it on briefly to clear the windows.
This practice ensures that every fiber and synthetic surface in the car will become saturated with moisture (common plastics will adsorb 1-3% of their weight in H2O). When the windshield cools off by radiative cooling and becomes cooler than the rest of the interior, that moisture migrates to the windshield.
The button to press is Auto. Even if you set the Temp to the minimum, the CC will control recirculation to manage humidity in the car, any added heat will ensure that humidity in the car is lower than ambient, and I'll bet the problem will go away completely. The impact on range will be minimal if the temp is set low.
In fact, since we both live in Portland, I'll bet the OP a beer that if he drives around with the CC set to Auto at any temp, he'll never see condensation again.
As I understand it, the OP drives with the climate control off, except when he turns it on briefly to clear the windows.
This practice ensures that every fiber and synthetic surface in the car will become saturated with moisture (common plastics will adsorb 1-3% of their weight in H2O). When the windshield cools off by radiative cooling and becomes cooler than the rest of the interior, that moisture migrates to the windshield.
The button to press is Auto. Even if you set the Temp to the minimum, the CC will control recirculation to manage humidity in the car, any added heat will ensure that humidity in the car is lower than ambient, and I'll bet the problem will go away completely. The impact on range will be minimal if the temp is set low.
In fact, since we both live in Portland, I'll bet the OP a beer that if he drives around with the CC set to Auto at any temp, he'll never see condensation again.
Resurrecting to see if OP found a solution to this. I do drive with automatic climate control on. However there are extreme levels of condensation on the interior of the vehicle both while driving and parked. Something clearly isn't right here.
Also, I am located in central NY. Have had the issue at all temps. Extra terrible in winter when I come out to the car and there is a coat of ice on the inside of the windshield :shock:
Also, I am located in central NY. Have had the issue at all temps. Extra terrible in winter when I come out to the car and there is a coat of ice on the inside of the windshield :shock: