Date   
Re: Payload Power Sources

Joe WB9SBD
 

DUH?!

I shouldn't be reading charts at like 3 AM. UG!

Thanks to all who answered my BrainFart!

Joe WB9SBD

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

On 3/27/2020 8:13 AM, BASE_DePauw wrote:
Joe,

The graph that you have shared has the horizontal axis in units of Ah (Ampere*hours) not in hours.  It is fine.

This means that all current draws are about 7.5 Amp hours with the smaller draws performing better than the large draw.

Howard, KC9QBN
BASE_DePauw



On Fri, Mar 27, 2020 at 9:02 AM Joe WB9SBD <nss@...> wrote:
I am very confused on a battery pack.

Say you have a pack that can run 1 amp of current draw for 10 hours.
One would think that if you only drew 0.5 amps that it should run for 20 hours or close to it true?

Now many of you old timers here will remember these awesome surplus packs that looked like this.

These things were OLD like 20 years old when we used them yet the power they could provide was incredible!
They were rated at 7500mah, incredible! Sadly this supply of "NOS" dried up and new packs were very prohibitive in prices. Easily ending up being like $100 bucks a flight!

But I found a source for Brand new ones, that would make it like $15 to $30 bucks a flight! YES!

But it's performance curve makes absolutely no sense to me!

This makes zero sense at all. I can draw 2 amps  or 0.25 amps and it changes the lasting run time by only like 15 minutes?

That doesn't make any sense!

Joe WB9SBD
--

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com



--
Howard L. Brooks
Professor of Physics and Astronomy
241 Julian Science and Mathematics Center
DePauw University
2 E. Hanna Street
Greencastle, IN 46135
hlbrooks@...
Office: (765) 658-4653
FAX: (765) 658-4732

Re: Payload Power Sources

Hank Riley
 

Run time to a 24 volt cutoff because the effects on the capacity are clearer.

On the closeup graph view C1, C2 and C3 are the capacities for 2 amps, 1 amp, and .5 amp and lower.  That means at this cutoff voltage the ultimate capacity is reached at .5 amp and anything less for current drain does not lead to a higher A-H capacity.

C1(2)  is ~ 7.0   A-H  
C2(1)  is ~ 7.35  A-H       5.0% increase with respect to 2 amp capacity
C3(.5) is ~ 7.6   A-H       8.6% increase with respect to 2 amp capacity 

So runtime for 2 amps drain is 7/2 = 3.5 hours.

The other runtimes for 1 amp and .5 amp are 7.35 and 15.2 hours.

I've left off some of the units in the equation for 2 amps but as a check A-H divided by amps gives a result in hours so the units are dimensionally valid.


Inline image








Re: Payload Power Sources

Hank Riley
 

Joe,

You're just reading or interpreting the curves the wrong way.  The X or horizontal axis is A-H, not run time.

The greater the current, the lower the A-H time.  So in your example of .5 amp versus 1 amp, the .5 amp run time will be a little over twice the hours.  And to continue, the .25 amp run time will be a little over twice what the .5 amp run time was.

I'll do the actual numbers in next email.

Hank
____________________________________________________________


On Friday, March 27, 2020, 09:02:24 AM EDT, Joe WB9SBD <nss@...> wrote:

I am very confused on a battery pack.

Say you have a pack that can run 1 amp of current draw for 10 hours.
One would think that if you only drew 0.5 amps that it should run for 20 hours or close to it true?


Re: Payload Power Sources

David Akerman
 

The discharge capacity in Ah changes a little, due to internal I2R losses, so you get a bit more Ah from lower currents vs higher currents.  That's also why the voltage is a bit lower.  It's not showing you the run time directly - you need to divide Ah by A to get h, so your 0.25A load will run for more than 8 times the 2A load will.


On Fri, 27 Mar 2020 at 13:02, Joe WB9SBD <nss@...> wrote:
I am very confused on a battery pack.

Say you have a pack that can run 1 amp of current draw for 10 hours.
One would think that if you only drew 0.5 amps that it should run for 20 hours or close to it true?

Now many of you old timers here will remember these awesome surplus packs that looked like this.

These things were OLD like 20 years old when we used them yet the power they could provide was incredible!
They were rated at 7500mah, incredible! Sadly this supply of "NOS" dried up and new packs were very prohibitive in prices. Easily ending up being like $100 bucks a flight!

But I found a source for Brand new ones, that would make it like $15 to $30 bucks a flight! YES!

But it's performance curve makes absolutely no sense to me!

This makes zero sense at all. I can draw 2 amps  or 0.25 amps and it changes the lasting run time by only like 15 minutes?

That doesn't make any sense!

Joe WB9SBD
--

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

Re: Payload Power Sources

BASE_DePauw
 

Joe,

The graph that you have shared has the horizontal axis in units of Ah (Ampere*hours) not in hours.  It is fine.

This means that all current draws are about 7.5 Amp hours with the smaller draws performing better than the large draw.

Howard, KC9QBN
BASE_DePauw



On Fri, Mar 27, 2020 at 9:02 AM Joe WB9SBD <nss@...> wrote:
I am very confused on a battery pack.

Say you have a pack that can run 1 amp of current draw for 10 hours.
One would think that if you only drew 0.5 amps that it should run for 20 hours or close to it true?

Now many of you old timers here will remember these awesome surplus packs that looked like this.

These things were OLD like 20 years old when we used them yet the power they could provide was incredible!
They were rated at 7500mah, incredible! Sadly this supply of "NOS" dried up and new packs were very prohibitive in prices. Easily ending up being like $100 bucks a flight!

But I found a source for Brand new ones, that would make it like $15 to $30 bucks a flight! YES!

But it's performance curve makes absolutely no sense to me!

This makes zero sense at all. I can draw 2 amps  or 0.25 amps and it changes the lasting run time by only like 15 minutes?

That doesn't make any sense!

Joe WB9SBD
--

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com



--
Howard L. Brooks
Professor of Physics and Astronomy
241 Julian Science and Mathematics Center
DePauw University
2 E. Hanna Street
Greencastle, IN 46135
hlbrooks@...
Office: (765) 658-4653
FAX: (765) 658-4732

Payload Power Sources

Joe WB9SBD
 

I am very confused on a battery pack.

Say you have a pack that can run 1 amp of current draw for 10 hours.
One would think that if you only drew 0.5 amps that it should run for 20 hours or close to it true?

Now many of you old timers here will remember these awesome surplus packs that looked like this.

These things were OLD like 20 years old when we used them yet the power they could provide was incredible!
They were rated at 7500mah, incredible! Sadly this supply of "NOS" dried up and new packs were very prohibitive in prices. Easily ending up being like $100 bucks a flight!

But I found a source for Brand new ones, that would make it like $15 to $30 bucks a flight! YES!

But it's performance curve makes absolutely no sense to me!

This makes zero sense at all. I can draw 2 amps  or 0.25 amps and it changes the lasting run time by only like 15 minutes?

That doesn't make any sense!

Joe WB9SBD
--

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

Re: Great Floater Race

stan siems
 

I think it sounds like a Great idea. Hope every one on here is  ok  group kind of died this week!

Stan

On 3/26/2020 3:53 PM, Jim Reed wrote:
I thought I read at one time that some were thinking about doing this. MN starts distance learning on March 30 as do many other states. We would love to build some lessons around it for our students. If you do this activity, please let us know. It would be fun to follow.

Take care everybody and stay safe!

Jim Reed

Great Floater Race

Jim Reed
 

I thought I read at one time that some were thinking about doing this. MN starts distance learning on March 30 as do many other states. We would love to build some lessons around it for our students. If you do this activity, please let us know. It would be fun to follow.

Take care everybody and stay safe!

Jim Reed

programing problem HELP

stan siems
 

I have a lightaprs w I just received and am working on programing it.   I down loaded and installed the driver, installed the latest Arduino pgm. As instructed I open Arduino go to preferences  type in the address for mightycore  go to tools -board manager and the down load is not there! and there is an error message that it failed to download. What am I doing wrong!

Thanks Stan

Re: The properties of latex / was Re: [GPSL] COVID-19 and GPSL

BASE_DePauw
 

This conversation reminds me of some work my students did several years ago.  Attached are a few slides from our presentation at the 2013 GPSL in Pella.

That work was inspired by Ron K6RPT's long duration floaters and relates to Joe WB9SBD's comments about the stretching of latex.

If you revisit CNSP (Ron's) flight to Morroco, the float altitude increased each daylight period.  A  simple explanation would be that the strong UV in the stratosphere degraded the latex, reducing its tensile strength, and eventually allowing the balloon to reach burst diameter.

Howard, KC9QBN
BASE_DePauw

Re: The properties of latex / was Re: [GPSL] COVID-19 and GPSL

Joe WB9SBD
 

I was just wondering what the tensile strength on the average actually was. So then even when fully inflated how much pressure it could actually generate before failing.

I had all the formulas for pressure vs diameter skin effect it was a pretty complex formula,

Funny thing was my bench tests came in very very close to the tests that someone made with a pressure gauge!

Joe WB9SBD

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

On 3/22/2020 8:36 PM, Hank Riley via Groups.Io wrote:
Joe,

When you say "many many" I'm curious why you did those tests?  Any special reason other than curiosity?

Do you have any tables or graphs you could provide, or write up for this list?

Hank
_____________________________________


On 3/22/2020 3:29 PM, Joe WB9SBD wrote:

We have tension tested many many samples of latex

The properties of latex / was Re: [GPSL] COVID-19 and GPSL

Hank Riley
 

Joe,

When you say "many many" I'm curious why you did those tests?  Any special reason other than curiosity?

Do you have any tables or graphs you could provide, or write up for this list?

Hank
_____________________________________


On 3/22/2020 3:29 PM, Joe WB9SBD wrote:

We have tension tested many many samples of latex

Re: COVID-19 and GPSL

stan siems
 

Another important factor to consider is the variation in temperature between the day and night, since many materials are known to act differently in different temperatures. For    this study one concern is that the temperature might drop down below the glass transition temperature (Tg) of the natural latex used to create the balloons. Going below the  Tg   would cause a definite change in the behavior of the material; materials above their Tg still retain elasticity, whereas those cooled below their  Tg become glassy and brittle.22This may cause the balloon to burst more quickly, especially considering the pressure and changes of volume the balloon experiences in its ascent. The Tg value of natural rubber latex is73Celsius.23Since an average day flight will see temperatures of below40Celsius in the upper troposphere should night temperatures drop to the range of65Celsius, it is possible that the natural latex rubber of the weather balloon will experience temperatures that would cause it to undergo glass transition

On 3/22/2020 3:29 PM, Joe WB9SBD wrote:
Finally,

Some evidence, But not totally also.

I wonder how must is lost when the latex is NOT stressed?

Like stretched ONLY to 50% elongation.

We have tension tested many many samples of latex, and it is amazing on how linear the force is when a piece is being stretched. From barely stretched to right at the end like 99% of it's stretchability  the forces only change like 10%

But that last bit it the force to pull it any further skyrockets! ten times or more the rest of the force, and the amount it continues to stretch is like nothing.

You can even easily feel this by hand. Take a scrap of a balloon and cut say a 1" wide strip from it. Now start to pull,  the force is more or less the same then it like hit a brick wall where it does not want to let you stretch any more then finally breaks.

Hence the flight that lasted two or three days that went from California to Morocco.

Joe WB9SBD

On 3/22/2020 3:16 PM, stan siems wrote:




Here is your answer
by DC Handke - ‎2019
May 1, 2019 - al (2013) examined the degradation of latex films in different environments. The degradation rate was most strongly linked to treatments with the most solar radiation, causing the fastest rate of breakdown. Photo-oxidation was the primary pathway for this degradation. This occurred in response to UV light from the sun.

Re: COVID-19 and GPSL

Michael Hojnowski
 

On 3/22/2020 1:52 PM, Michael wrote:
My original post on this suggested classes, unlimited, party ballon, etc. an we could additionally qualify winning with fastest laps, distance traveled, countries crossed, nearly an unlimited number of classes including fun ones like born again, slowest, etc
I think another interesting category would be "most horrible launch conditions, but still got a pico to float".  I'm sure the weather won't be perfect for everyone, if we're doing this from "all over".   That might have to be juried with video submissions or something.

I'd definitely support different classes for party balloons vs SBS envelopes.  They're a totally different ballgame.

Mike / KD2EAT

Re: COVID-19 and GPSL

Joe WB9SBD
 

Finally,

Some evidence, But not totally also.

I wonder how must is lost when the latex is NOT stressed?

Like stretched ONLY to 50% elongation.

We have tension tested many many samples of latex, and it is amazing on how linear the force is when a piece is being stretched. From barely stretched to right at the end like 99% of it's stretchability  the forces only change like 10%

But that last bit it the force to pull it any further skyrockets! ten times or more the rest of the force, and the amount it continues to stretch is like nothing.

You can even easily feel this by hand. Take a scrap of a balloon and cut say a 1" wide strip from it. Now start to pull,  the force is more or less the same then it like hit a brick wall where it does not want to let you stretch any more then finally breaks.

Hence the flight that lasted two or three days that went from California to Morocco.

Joe WB9SBD

On 3/22/2020 3:16 PM, stan siems wrote:




Here is your answer
by DC Handke - ‎2019
May 1, 2019 - al (2013) examined the degradation of latex films in different environments. The degradation rate was most strongly linked to treatments with the most solar radiation, causing the fastest rate of breakdown. Photo-oxidation was the primary pathway for this degradation. This occurred in response to UV light from the sun.

Re: COVID-19 and GPSL

Joe WB9SBD
 

I have been doing this for over 30 years, And I have heard people make these statements probably a thousand times, but I have yet so see some actual real evidence of it.

Joe WB9SBD

On 3/22/2020 3:06 PM, stan siems wrote:

It Is a FACT!!  n There is all kinds of information on it.


Re: COVID-19 and GPSL

stan siems
 




Here is your answer
by DC Handke - ‎2019
May 1, 2019 - al (2013) examined the degradation of latex films in different environments. The degradation rate was most strongly linked to treatments with the most solar radiation, causing the fastest rate of breakdown. Photo-oxidation was the primary pathway for this degradation. This occurred in response to UV light from the sun.

Re: COVID-19 and GPSL

Mark Conner N9XTN
 

It's obvious that there is enthusiasm for a virtual GPSL for this year if it should be necessary.  I will be contacting UNO in the near future to see if they have already made decision about the campus for the summer session.  

We will also work to broadcast the sessions in some form whether we do a virtual or in-person GPSL.  I think the UNO venue has the ability to support that with decent sound (wireless mic for presenter, audience mic for questions).

I am watching an Omaha news conference where the head of the Nebraska Med Center is saying he expects restrictions to be in place for 10-12 weeks, which would bring us into June.  If that happens, that may be a little late to make venue arrangements.  I am still thinking that if we don't have a high probability of pulling off an in-person event by June 1, we'll decide to go virtual.  

If we do have an in-person GPSL, I'd like to encourage others who don't attend to launch at the same time from their own sites.  It'd be fantastic to see as many balloons as possible in the air at the same time.  I propose a launch time of 1400Z (10am ET/7am PT) on July 11th to allow for maximum participation across the US and Canada yet still have plenty of the day for recovery.  Also, a mix of floaters and conventional balloons would be nice to see as well.

73 de Mark N9XTN






On Tue, Mar 17, 2020 at 9:19 PM Mark Conner <mconner1@...> wrote:
I've had a couple of emails asking about GPSL 2020 in light of the COVID-19 outbreak.  

So far, there is nothing that would prevent us from going forward.  However, I have indirectly heard that the University of Nebraska system is doing some (contingency?) planning for teaching summer classes online only.  Our Friday session is planned to be at Nebraska's Omaha campus - if that is closed, we'd have to relocate.

Of course, at this date, it's hard to say whether various travel and gathering restrictions will be lifted in the next four months - I'm sure we all hope so.

I'm not sure how far in advance attendees will have to make commitments that will be hard to get out of.  I assume we'd have to fish or cut bait by around June 1st.  If your group would need an earlier decision, let me know.

73 de Mark N9XTN

Re: COVID-19 and GPSL

stan siems
 

It Is a FACT!!  n There is all kinds of information on it.

On 3/22/2020 2:56 PM, Joe WB9SBD wrote:
That did NOT answer either of my questions.

Joe WB9SBD
On 3/22/2020 2:48 PM, stan siems wrote:

latex balloons degrade very fast when exposed to UV  especially so at high altitude. also get brittle at 130 deg temps


On 3/22/2020 2:39 PM, Joe WB9SBD wrote:
Michael,

Do you know this as a fact, or something you have heard?

And degrade fast, how fast is fast?

Joe WB9SBD

On 3/22/2020 1:47 PM, Michael wrote:
The latex balloons degrade quickly in UV so a longer flight can be realized with a UV resistant envelope, Ron makes these in his shop. 

--Michael Willett

On Mar 22, 2020, at 1:34 PM, Jerry via Groups.Io <jerrygable@...> wrote:

My understanding is Ron Meadows started http://www.scientificballoonsolutions.com/.  One of these balloons was what Alan Adamson used on his 2 year flight.  Ron originally did flights on latex balloons with distance and longevity as the goal.  One of his latex balloons went from California to Morocco.


Jerry Gable
Balloon Flight Prediction tools
http://www.s3research.com


On Sunday, March 22, 2020, 11:20:49 AM MST, stan siems <ssiems@...> wrote:


who is Ron and what are his balloons?  I have only been here for a few days  newbe old guy!!

On 3/22/2020 12:52 PM, Michael wrote:
My original post on this suggested classes, unlimited, party ballon, etc. an we could additionally qualify winning with fastest laps, distance traveled, countries crossed, nearly an unlimited number of classes including fun ones like born again, slowest, etc

--Michael Willett

On Mar 22, 2020, at 11:58 AM, Jerry via Groups.Io <jerrygable@...> wrote:

We could do the floater race even if we have an in person gpsl.  As Stan pointed out, do we need weight or size classes?  What if I go buy one of Ron's big balloons?

Jerry Gable
Balloon Flight Prediction tools
http://www.s3research.com


On Sunday, March 22, 2020, 9:37:26 AM MST, Bill Brown via Groups.Io <wb8elk@...> wrote:


I'm all for a simultaneous Floater Race if we do a virtual GPSL.

- Bill WB8ELK


-----Original Message-----
From: Michael <mw@...>
To: GPSL <GPSL@groups.io>
Sent: Sat, Mar 21, 2020 9:11 am
Subject: Re: [GPSL] COVID-19 and GPSL

How about a race? I’ve yet to do a round the world floater and would like to. Each of us put out $$$ for attending GPSL (when we can get there) which could be spent on a floater project. Our virtual presentations could be floater project centric and the race broken down into unlimited class, party balloon class, etc with weighting favoring experiments / capabilities. 

--Michael Willett
K5NOT 

On Mar 21, 2020, at 8:53 AM, BASE_DePauw <hlbrooks@...> wrote:

Stan,

EBBE is short for Earth-Balloon-Balloon-Earth radio transmission link.  A ground based amateur radio operator contacts a distant operator using two high altitude balloons with repeater radios to extend the range of radio contact.  It allows for contact over the horizon, which normally is not possible for many radio frequencies.

Howard, KC9QBN
BASE_DePauw

On Sat, Mar 21, 2020, 9:42 AM stan siems <ssiems@...> wrote:
what is EBBE flight?
On 3/20/2020 10:58 PM, L. Paul Verhage KD4STH wrote:
I don't have a lot of help here, so I may want to travel and launch with a group. That all depends of course how the situation looks this summer.

On Fri, Mar 20, 2020, 2:42 PM Joe WB9SBD <nss@...> wrote:
I propose, everyone we have the virtual meeting online using one of the many programs that do that sort of thing.

The when it comes to launch day we all launch from our usual launch sites.

I'd still love do do our EBBE flight, but have yet to find a willing partner group to try it.

Joe WB9SBD
Near Space Sciences

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

On 3/20/2020 10:58 AM, Keith Kaiser, WA0̷TJT wrote:
HamSCI is in the middle of a Zoom workshop right now. Its working great and I think we should make GPSL 2020 a virtual set of presentations with a coordinated launch on Saturday.

Keith, WA0̷TJT






Re: COVID-19 and GPSL

Joe WB9SBD
 

Thank You,

If my up coming flights are successful I will be putting this to a rest. once and for all how long they last.

But not quite ready yet.

Joe WB9SBD

On 3/22/2020 3:01 PM, Michael wrote:
Heard, and not a fact I can put my arms around completely, but have seen the latex balloon bits turn dark yellow and harden when I left a piece out in the sun for a while. I’ll need to do this again under more controlled conditions.

--Michael Willett