Will my weather balloon work in the Stratosphere?

[Max CR]

Homework Statement

Hi, I am trying to launch a weather balloon. I am thinking that I would use the following item for a heater. The link is in the body of this post. I would like to use the heater in order to keep an attached iPhone warm and functioning. It states that it works at the temperature of 95 degrees Fahrenheit to 122 degrees Fahrenheit. Will this work on a iPhone on a weather balloon 19 miles above the surface in the Stratosphere where it is -60 degrees Fahrenheit? Also, I will use the USB adapter to keep it powered on and warm the whole way to the launch site. Please let me know if this is a good match for a heater trying to keep an iPhone warm and functioning? Thank you.

Relevant Equations

Will the weather balloon's iPhone work at such temperatures with the heating pad?

https://www.amazon.com/Heating-Electric-Heater-Element-Warming/dp/B07RQK2GP4/?tag=pfamazon01-20

 

[phinds]

You really think you can put up a personal weather balloon that will go that high? It's pretty much as high as the highest professional weather balloon has ever gone.

EDIT: OOPS ... seems I'm behind the times on weather balloons and they go much higher now.

 

[hutchphd]

How will this be powered??? Electronics is usually happy to be cold.....I guess LCD would be a problem, but what do you care about the LCD?? (unless the unit itself cares for some reason) I think a little bit more thought about this is indicated........maybe more than a little ....?

 

[Tom.G]

Will the weather balloon's iPhone work at such temperatures with the heating pad?

It could if you wrap several inches of thermal insulation around the iPhone with the heater inside. Since the heater is USB powered, there will be only 5 Watts of power, or 17BTU/Hr, of heating available. (1 BTU is the energy needed to raise 1 US pound of water by 1 degree F.)

A somewhat bigger problem is that batteries do not work well, or at all, at -60 degrees. Even military grade batteries need to be heated when used at -40 degrees. (this is often done by short-circuiting the battery for a short time to warm it up! not especially recommended for civilian use, a circuit failure could result in sudden spectacular battery failure.)

You could use a larger battery pack and also put heaters and insulation around the batteries.

Cheers,
Tom

p.s. Please keep us posted on your progress and results, we like to learn too!

 

[berkeman]

Please be mindful of the regulations that you need to abide by for weather balloon (high altitude balloon) launches:

https://stratostar.com/can-i-launch-a-weather-balloon/

 

[hutchphd]

ou could use a larger battery pack and also put heaters and insulation around the batteries.

`It probably makes more sense to just insulate the heck out of the phone +batteries and let the selfheating work for you. Aluminized mylar/Kapton wrap (like spacecraft..... let the low air pressure work for you)? How can you get the RF signal out through?

 

[Max CR]

Hi everyone. I was asked to post this. The weather balloon was a huge success.

The launch of the weather balloon:

The making of the weather balloon:

 

[erobz]

Looked like a heck of a day! Congratulations on the successful launch and recovery!