Do you leave your drone in a hot car.

[Former Member]

True. But that is when moisture and temperatures are at equilibrium. If I take a 5° battery and go outside when its 5°, then no problems. But if I take a 5° battery and go outside and its 20° then moisture vapor will condense on the battery and the internals. The humidity is higher when the temperature is higher and a cold battery will bring the moist air to its dew point causing condensation. Especially in a confined space, like the internals of a battery, the condensation can cause corrosion between contact points which in turn causes an increase in resistance. That causes higher voltage and will damage connections that are not designed to carry those higher voltages. Arcing and further deterioration will result.

By the way, welcome to the forum. Your obvious experience with electronics is welcome here as an asset.

 

[Don the engineer]

By the way, welcome to the forum. Your obvious experience with electronics is welcome here as an asset.

Thanks Thunderdrone. I'm a forensic engineer, so anything having to do with damage or failure is a specialty of mine. I appreciate the expertise of everyone here concerning drones as I've found it's been easier to do my own drone work than to hire someone and have to go back and forth to get the data I need.

If you are in a low humidity area like the states you mentioned (UT, AZ, CA, parts of TX) then the problem will not be much of an issue. In addition, if you did take a cold battery and it had condensation, as long as you run it until it's hot enough to evaporate the condensation, the problem is mitigated by essentially burning of any condensation. The worst case scenario is taking a cold battery into a hot and humid environment and not heating it up and then storing it. The condensation would form and would have sufficient time to cause corrosion.

And for one of the other questions, warmer air can "hold" a lot more moisture than cold air. Warm air causes evaporation and there's more moisture available to condense when the temperature is reduced. It's not really a function of holding moisture, it's just that there is more available at the surface where it has evaporated. As it cools it is likely to join with other droplets and condense causing fog, or in this case moisture in sensitive electronics.

 

[Former Member]

If you are in a low humidity area like the states you mentioned (UT, AZ, CA, parts of TX) then the problem will not be much of an issue. In addition, if you did take a cold battery and it had condensation, as long as you run it until it's hot enough to evaporate the condensation, the problem is mitigated by essentially burning of any condensation. The worst case scenario is taking a cold battery into a hot and humid environment and not heating it up and then storing it. The condensation would form and would have sufficient time to cause corrosion.

Im sure around 1,000 SW USA members are relieved to hear that.

 

[Thomas B]

Thanks Thunderdrone. I'm a forensic engineer, so anything having to do with damage or failure is a specialty of mine. I appreciate the expertise of everyone here concerning drones as I've found it's been easier to do my own drone work than to hire someone and have to go back and forth to get the data I need.

If you are in a low humidity area like the states you mentioned (UT, AZ, CA, parts of TX) then the problem will not be much of an issue. In addition, if you did take a cold battery and it had condensation, as long as you run it until it's hot enough to evaporate the condensation, the problem is mitigated by essentially burning of any condensation. The worst case scenario is taking a cold battery into a hot and humid environment and not heating it up and then storing it. The condensation would form and would have sufficient time to cause corrosion.

And for one of the other questions, warmer air can "hold" a lot more moisture than cold air. Warm air causes evaporation and there's more moisture available to condense when the temperature is reduced. It's not really a function of holding moisture, it's just that there is more available at the surface where it has evaporated. As it cools it is likely to join with other droplets and condense causing fog, or in this case moisture in sensitive electronics.

Cool! Much appreciate the input of a pro.
Question is, when does this effect cause noticeable decremental performance in these drones?

 

[Former Member]

Thanks Thunderdrone. I'm a forensic engineer, so anything having to do with damage or failure is a specialty of mine. I appreciate the expertise of everyone here concerning drones as I've found it's been easier to do my own drone work than to hire someone and have to go back and forth to get the data I need.

If you are in a low humidity area like the states you mentioned (UT, AZ, CA, parts of TX) then the problem will not be much of an issue. In addition, if you did take a cold battery and it had condensation, as long as you run it until it's hot enough to evaporate the condensation, the problem is mitigated by essentially burning of any condensation. The worst case scenario is taking a cold battery into a hot and humid environment and not heating it up and then storing it. The condensation would form and would have sufficient time to cause corrosion.

In your experience, do you have an idea of what battery temperature it would take to evaporate the internal condensation as you mention above? The battery can run at peak temp of around 100-100° but that is only after 3-5 minutes of run time.

 

[Don the engineer]

Their collective

Im sure around 1,000 SW USA members are relieved to hear that.

Their collective sigh of relief was likely audible.?

 

[Former Member]

Their collective

Their collective sigh of relief was likely audible.?

Im sorry to be a pest, but how would you safely store your batteries in a car? A cooler with freezer packs (non water) was recommended by a member. Would a desiccant in the cooler reduce condensation?

 

[AMann]

Why is the humidity higher when the temp is higher? Don’t follow.

Warm air can hold more moisture than cold - if it’s available.

That’s why warm air rising leads to water vapor condensation (cloud and thunderhead formation) as it cools.

 

[Don the engineer]

In your experience, do you have an idea of what battery temperature it would take to evaporate the internal condensation as you mention above? The battery can run at peak temp of around 100-100° but that is only after 3-5 minutes of run time.

As long as the temperature of the entire component is brought above the dew point temperature it wont be a problem. So today the dewpoint in Phoenix is 38°F. As long as the entire system is brought above that temp it wont be a problem. It's likely that if the exterior of the battery is above 100°F for as little as 5 minutes then the more insulated areas of the system are above 38°F.

As a general precaution, those little packs of silicate desiccants would be an easy way of absorbing any moisture inside a storage case. Next time you buy a pair of shoes or especially furniture, save the desiccant pack and keep it in your storage case.

 

[Former Member]

As long as the temperature of the entire component is brought above the dew point temperature it wont be a problem. So today the dewpoint in Phoenix is 38°F. As long as the entire system is brought above that temp it wont be a problem. It's likely that if the exterior of the battery is above 100°F for as little as 5 minutes then the more insulated areas of the system are above 38°F.

As a general precaution, those little packs of silicate desiccants would be an easy way of absorbing any moisture inside a storage case. Next time you buy a pair of shoes or especially furniture, save the desiccant pack and keep it in your storage case.

Excellent. Would those little packs help reduce the internal condensation of the packs or mostly external on the batteries surface? Any idea how many packs would need to be used?

One last thing. Would a cheapo temperature/humidity thermometer inside the cooler help determine if the batteries will be above dew point when you take them out?

 

[Don the engineer]

Im sorry to be a pest, but how would you safely store your batteries in a car? A cooler with freezer packs (non water) was recommended by a member. Would a desiccant in the cooler reduce condensation?

No. The problem isnt happening when it's cold. It's when you take it out. Desiccants absorb moisture from the air and would eventually reduce the moisture inside the pack as moisture is maintained by equilibrium throughout the volume of air.

I wouldnt try to keep the batteries cold at all times. Just in preparation for a job that you know you'll need them. Then get them warm enough to dry out and store them dry with the desiccants.

If you had one of those peltier based coolers and you could adjust the temperature, then yes, set the temperature to be just above the dewpoint and you shouldnt have any problems.

 

[Thomas B]

Warm air can hold more moisture than cold - if it’s available.

That’s why warm air rising leads to water vapor condensation (cloud and thunderhead formation) as it cools.

Understand... but high or lower temp doesn’t of course, dictate higher or lower humidity.

 

[AMann]

No. The problem isnt happening when it's cold. It's when you take it out. Desiccants absorb moisture from the air and would eventually reduce the moisture inside the pack as moisture is maintained by equilibrium throughout the volume of air.

I wouldnt try to keep the batteries cold at all times. Just in preparation for a job that you know you'll need them. Then get them warm enough to dry out and store them dry with the desiccants.

If you had one of those peltier based coolers and you could adjust the temperature, then yes, set the temperature to be just above the dewpoint and you shouldnt have any problems.

One could put a temporary single layer wrap on the battery to seperate it from the ambient air moisture... wonder how a piece of that self sticking SaranWrap would do. I believe it would stick to the drone body as well. For cold weather fliers, they could put a small piece of foam under the wrap over the battery too.

 

[Don the engineer]

Understand... but high or lower temp doesn’t of course, dictate higher or lower humidity.

Not by itself. It's an important factor but so is available moisture, pressure, and chemical composition of the environment affecting free moisture. Humidity isnt a problem in a salt mine. Cold or hot.

 

[AMann]

Understand... but high or lower temp doesn’t of course, dictate higher or lower humidity.

Thats what I meant by if moisture is available. Cold air over the ocean or a forest cannot hold as much water vapor as warm air over the same. But it’s Relative Humidity that changes with temperature - the difference between what the air actually holds to what it can hold at saturation depends on temperature and pressure.

 

[Former Member]

Not by itself. It's an important factor but so is available moisture, pressure, and chemical composition of the environment affecting free moisture. Humidity isnt a problem in a salt mine. Cold or hot.

How about this, along the lines of what @AMann suggested... Could you put the battery/batteries in a ziploc with a desiccant pack, ziploc it closed, throw it in the cooler at 50°f and succeed in keeping the condensation out of the battery while also lowering the starting battery temperature? So easy, and if it works in cooling the battery without building condensation inside the battery, you have won the war, or at least that battle.

 

[Don the engineer]

How about this, along the lines of what @AMann suggested... Could you put the battery/batteries in a ziploc with a desiccant pack, ziploc it closed, throw it in the cooler at 50°f and succeed in keeping the condensation out of the battery while also lowering the starting battery temperature? So easy, and if it works in cooling the battery without building condensation inside the battery, you have won the war, or at least that battle.

Your proposed solution would mitigate the likelihood of moisture problems. But I would also include one additional step. When you bring it out of the cold, make sure you use it and get it good and hot when you do. Dont just take it of the cold and throw it in the bird to store at room temp.

 

[Former Member]

Your proposed solution would mitigate the likelihood of moisture problems. But I would also include one additional step. When you bring it out of the cold, make sure you use it and get it good and hot when you do. Dont just take it of the cold and throw it in the bird to store at room temp.

Excellent advice. Listen up children! hahaha

 

[Former Member]

Your proposed solution would mitigate the likelihood of moisture problems. But I would also include one additional step. When you bring it out of the cold, make sure you use it and get it good and hot when you do. Dont just take it of the cold and throw it in the bird to store at room temp.

Do you think the desiccant packs are reusable? Do you think they have a lifespan if they are used constantly to dehumidify a damp battery?

 

[Don the engineer]

Do you think the desiccant packs are reusable? Do you think they have a lifespan if they are used constantly to dehumidify a damp battery?

Absolutley reusable, especially the silica gel packs. The clay based ones are not as resilient.

Just leave the pack on the dash board with a window cracked on a hot day. Cheap dehydrator.