Condensation explained

[aermale]

Before you run out the door with your quad in winter, you should understand how condensation works. The temperature drop between our homes or cars and the outside air can cause a considerable amount of moisture, inside your ac, despite your best efforts to keep it dry. An ac could be fully functional inside your home, and have a catastrophic failure, immediately after going outside, due to unseen condensation.

Warmer air has the ability to hold much more moisture than cold air. Relative humidity defines the percentage of moisture the air contains, compared to the amount it could possibly contain. As warm air cools, it's relative humidity rises, lowering the amount of moisture it can hold. So, the warm air inside your drone can hold plenty of moisture, without releasing it into the atmosphere. However, as it cools, it loses the ability to hold the moisture and it is released, in the form of condensation, deposited into your IMU, for example. This can wreak havoc on electronics, especially something as sophisticated as a phantom.
So, as you're unpacking your bird, it's filled with warm air(most likely). The warm air contains a certain amount of humidity, and it doesn't hurt anything. When you take it outside in winter, the air rapidly cools and it loses its ability to hold the moisture in the form of humidity. Its then deposited as water into your bird.

The same could happen in reverse for a hot summer day. When the bird comes out of the hot sun and into an air conditioned environment, the condensation may form. The difference would be that you're done flying.

Avoiding massive temperature drops before flight may save you a large repair bill, or worse. A solution might be to slowly adjust the ac to the different temperature, but avoiding it altogether may be the best idea. I thought I'd contribute something helpful, after my last thread went off the rails. Im here to contribute to the community, after all. If I got it wrong, let me know. If you have a good idea, chime in and sorry if you already knew all this. Thanks for reading.

 

[Kirby Johnson]

Before you run out the door with your quad in winter, you should understand how condensation works. The temperature drop between our homes or cars and the outside air can cause a considerable amount of moisture, inside your ac, despite your best efforts to keep it dry. An ac could be fully functional inside your home, and have a catastrophic failure, immediately after going outside, due to unseen condensation.
Warmer air has the ability to hold much more moisture than cold air. Relative humidity defines the percentage of moisture the air contains, compared to the amount it could possibly contain. As warm air cools, it's relative humidity rises, lowering the amount of moisture it can hold. So, the warm air inside your drone can hold plenty of moisture, without releasing it into the atmosphere. However, as it cools, it loses the ability to hold the moisture and it is released, in the form of condensation, deposited into your IMU, for example. This can wreak havoc on electronics, especially something as sophisticated as a phantom.
Avoiding massive temperature drops before flight may save you a large repair bill, or worse. A solution might be to slowly adjust the ac to the different temperature, but avoiding it altogether may be the best idea. I thought I'd contribute something helpful, after my last thread went off the rails. Im here to contribute to the community, after all. If I got it wrong, let me know. If you have a good idea, chime in and sorry if you already knew all this. Thanks for reading.

Condensation is likely when a dry cold item is exposed to warm moist air, right? IE: Bringing in a drone which has been sitting outside AND not operating, and is cold through and through into the warm moist air in the house, like a cold soda does, right?

I've never seen it happen. With my big cameras with those glass lenses, they fog up when they have been in the Air Conditioning and I take them outside when it is 100 percent humidity here in Fla. But they N E V E R fog up coming back inside. IE: your air inside never gets anywhere close to the outside humidity in summer. The reason is that the inside air is actually just outside air which has been heated. So it originally had X amount of water in it. Then when your furnace heats it , it still has the same amount of water, but because hot air can contain more water, it's relative humidity goes way down. That is why people have humidifiers in the winter.

But thanks for trying.

 

[aermale]

No. Condensation would be likely if exposing warm, moisture rich air to colder temperatures. It loses its ability to hold the moisture and condensation forms.


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[aermale]

People use humidifiers in winter, because the air has lost its ability to hold moisture. It adds a level of humidity to the air for comfort.

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[aermale]

Using your analogy of the soda can, the air around the can is rapidly cooling, due to the cold contents. As the surrounding air cools, it loses its ability to hold moisture. The warmer air around the can is cooled, the relative humidity rises, and the cooled air deposits its moisture onto the outside of the can.

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[ChiefStealth]

Well, there's two places my drone will be. Inside the house, where the humidity is 40% because the furnace is running, because its cold. And, the drone will be outside, in low humidity air, because I don't fly in the rain, or when humidity is high. So, I don't put the drone in any high humidity situations where it could get condensation on it.
Knowing how your drone could get condensation is smart. Knowing how to avoid condensation is smarter.

 

[Monte55]

The reason that people will use humidifiers in winter is....let's say it's 20 degrees F outside and the RH is 60 %. The air in the house comes from the outside. Now when that air is heated to 70 degrees F, It expands to a larger volume and the moisture it had covers much more volume now so the RH goes down.
The biggest problem with condensation is when taking a cold object and subjecting it to warm air. As the warm air hits the cold surface, it reaches its dew point and the water vapor changes to droplets .
Back in the days of shooting film, I would store my film in the freezer. Before I could use it, I had to let it warm up to ambient temperature before removing film from package. If not, moisture would develop on cold film and degrade the image.

 

[Monte55]

People use humidifiers in winter, because the air has lost its ability to hold moisture. It adds a level of humidity to the air for comfort.

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Earlier you said warm air can hold more moisture and now you say it has lost its ability to hold moisture...which is it?

 

[aermale]

The reason that people will use humidifiers in winter is....let's say it's 20 degrees F outside and the RH is 60 %. The air in the house comes from the outside. Now when that air is heated to 70 degrees F, It expands to a larger volume and the moisture it had covers much more volume now so the RH goes down.
The biggest problem with condensation is when taking a cold object and subjecting it to warm air. As the warm air hits the cold surface, it reaches its dew point and the water vapor changes to droplets .
Back in the days of shooting film, I would store my film in the freezer. Before I could use it, I had to let it warm up to ambient temperature before removing film from package. If not, moisture would develop on cold film and degrade the image.

This is an interesting strategy. We basically agree on how it happens, but we use different terns to describe it.

 

[Richard R]

Same reason that my eyeglasses fog up after I have been outside in the cold and come back into the warm, humidified house. The moisture usually evaporates as the glasses warm up, but I could see the risk of some moisture on the electronics pudding enough to cause problems.

 

[aermale]

Earlier you said warm air can hold more moisture and now you say it has lost its ability to hold moisture...which is it?

The colder, winter air does contain less moisture than warm air. Simply heating the air up doesnt add any humidity. In the interest of comfort, moisture is added through a humidifier. We don't use them in the south, but Im familiar with the concept.

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[Monte55]

The colder, winter air does contain less moisture than warm air. Simply heating the air up doesnt add any humidity. In the interest of comfort, moisture is added through a humidifier. We don't use them in the south, but Im familiar with the concept.

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The temp in my house now is about 65 degrees F and the RH is about 20%. The temp outside is 17F and 78% RH.

 

[aermale]

I was hoping people would chime in with some strategy to defeat this concept. Its really cold outside and my batteries are charged. I want to play....

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[aermale]

The temp in my house now is about 65 degrees F and the RH is about 20%. The temp outside is 17F and 78% RH.

Relative humidity or humidity?

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[N017RW]

It amazes me the excuses people come up with not to fly.

 

[aermale]

Thinking of relative humidity as a ratio, that would be correct. The 17 ° air outside can hold less moisture, therefore its at 78% capacity, compared to the warm air, which is only at 20% capacity.

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[Monte55]

Relative humidity or humidity?

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I said RH twice

 

[aermale]

It amazes me the excuses people come up with not to fly.

I'm not telling anyone not to go fly. I just felt like it was a discussion worth having. After a search, I couldn't find much info on the topic. So far, I've learned something, so its been a slight success at least.

I said RH twice

Sorry. I read it fast. No need to be testy on 2 of my threads in a row. Its just a discussion. I asked because I'm not familiar with measuring relative humidity, indoors. I get that it could be checked for outdoor air, via a weather forecast. I also understand how the humidity indoors could be measured. Sorry, if I'm missing something obvious. It's the point of discussion. [emoji5]

 

[Monte55]

Warm or hot air doesn't always have the most moisture. Did you know the Sahara desert has an average RH level of only about 25% ?. Do this. Take a clear drinking glass and put it in your freezer. Check it an hour later. Still clear. Now set it on the counter in the room. Now what happens. It starts to fog up. It all has to do with temp difference and atmospheric pressure. FYI, I have been in the HVAC business for over 40 years so I have a bit of a handle on this. , , T

 

[Monte55]

I'm not telling anyone not to go fly. I just felt like it was a discussion worth having. After a search, I couldn't find much info on the topic. So far, I've learned something, so its been a slight success at least.

Sorry. I read it fast. No need to be testy on 2 of my threads in a row. Its just a discussion. I asked because I'm not familiar with measuring relative humidity, indoors. I get that it could be checked for outdoor air, via a weather forecast. I also understand how the humidity indoors could be measured. Sorry, if I'm missing something obvious. It's the point of discussion. [emoji5]

I'm not being testy...just stating facts.