[NSRCA-discussion] Heat Sinks

[Earl Haury]

Jay

Is it possible to change the "set point" of these units by varying the input voltage?

Earl
  ----- Original Message ----- 
  From: Jay Marshall 
  To: jpavlick at idseng.com ; 'General pattern discussion' 
  Sent: Friday, August 01, 2008 2:04 PM
  Subject: Re: [NSRCA-discussion] Heat Sinks


  Peltiers are the units used in your car to provide a hot/cold portable food container.



  Jay Marshall 

  -----Original Message-----
  From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of John Pavlick
  Sent: Friday, August 01, 2008 11:44 AM
  To: nsrca-discussion at lists.nsrca.org
  Subject: Re: [NSRCA-discussion] Heat Sinks



  Yup that's one application though not the most effective use. You wouldn't want to dissipate a lot of energy like what this guy was trying to do. The neat thing about Peltiers is they can heat and cool depending on which direction the current flows. In other words, they can be used to control the temperature (up or down) and they're solid state so there are no moving parts. 



  Of course they require power to operate and it probably wouldn't be practical to use the batteries themselves as the source since you guys need every last drop of energy in them to run the motor. 



  Just something to think about. Kinda like a profile Pattern plane. LOL



  John Pavlick



  JEREMY CHINN <lagrue at hotmail.com> wrote: 

  With much the same question in mind, I found this with Google.....
   
  http://www.dansdata.com/peltprac.htm
   


  > Date: Fri, 1 Aug 2008 09:24:56 -0500
  > From: glmiller3 at suddenlink.net
  > To: jpavlick at idseng.com; nsrca-discussion at lists.nsrca.org
  > Subject: Re: [NSRCA-discussion] Heat Sinks
  > 
  > What the heck are Peltiers? Flying in LA I never have to worry about batteries being too COOL!
  > 
  > I'm always looking for a way to improve heat exchange, though. 
  > 
  > G
  > ---- John Pavlick <jpavlick at idseng.com> wrote: 
  > 
  > =============
  > You didn't fly fast enough to heat them up! <LOL> Seriously, LiPOs perform best within a certain temperature range. You electron heads should look into something that can keep the batteries within this range. Maybe Peltiers? These are nice because thay can generate heat OR provide a cooling effect. If anyone wants to explore this I'd be glad to help.
  > 
  > John Pavlick
  > 
  > JEREMY CHINN <lagrue at hotmail.com> wrote:
  > .hmmessage P { margin:0px; padding:0px } body.hmmessage { FONT-SIZE: 10pt; FONT-FAMILY:Tahoma } The assessment on my Kudzu at the Nats was that my batteries never even got to optimum operating temperature...... 
  > 
  > 
  > ---------------------------------
  > From: jpavlick at idseng.com
  > To: nsrca-discussion at lists.nsrca.org
  > Date: Thu, 31 Jul 2008 22:12:06 -0400
  > Subject: Re: [NSRCA-discussion] Heat Sinks
  > 
  > Sounds heavy. Don't electric airplanes have trouble making weight (except for Dave Lockhart's of course)? What are you guys doing for letting air in / out of the fuse. Without proper airflow, even a good heat sink won't work. Actually wouldn't it be better to make some kind of (light weight) thermostatically controlled cooling system? Cold LiPOs don't make optimum power.
  > 
  > John Pavlick
  > http://www.idseng.com
  > ----- Original Message ----- 
  > From: Earl Haury 
  > To: Discussion List, NSRCA 
  > Sent: Thursday, July 31, 2008 9:49 PM
  > Subject: [NSRCA-discussion] Heat Sinks
  > 
  > 
  > We all tend to mount E batteries on some sort of wooden / carbon / nomex shelf and tie them down with Velcro or a clamp plate - none of which are very good at transferring heat. Possibly we could improve heat transfer from the batts to the cooling air by using aluminum, or better yet - finned aluminum heatsink material for the shelf / clamp. 
  > 
  > I've spent a fair bit of time trying for find appropriate heatsink material online - something 4" long x 3" wide with a high count of thin, maybe 1/4 high, fins might work. Unfortunately, there's tons of heatsink material available from Newark, Mauser, etc. but it's difficult to find the right stuff - especially material light enough for our use. The closest I've come is Thermaflo # E1243, but I'm lacking a small quantity source. 
  > 
  > Anybody work with this stuff & have recommendations or sources?
  > 
  > Earl
  > 
  > ---------------------------------
  > 
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