2nd Prototype of DLSR cooler ( Some proper data !)

[simmo39]

Hi, after the first prototype proved the concept I went for a larger fan and heatsink on the second version. It seems to make all the difference, cooling the copper plate v quickly and with no vibration from the fan. I still need to work on the mounting but if it shows an improvement on my dark frame image experiment i may consider a permanent mounting to the back of the camera. Any advise and pointers welcome.

[nightvision]

Some info that might be useful; I did a lot of testing recently to try and optimise TEC/Heatsink/Fan combinations.  The test camera in this case was an ASI120MM, I found that by dropping the TEC voltage (on 12706 and similar TECs) to around 7 volts I was able to reduce the fan size and speed and reduce heatsink size and achieve better cooling.  I didn't use PWM.   In this case I was cooling the whole camera casing, for cold finger arrangements I think I could go smaller/quieter.   The conclusion I came to was that most TECs when driven at max voltage are way too powerful for the job and generate more heat than the item to be cooled.  I used one of these to adjust the TEC supply: http://www.ebay.co.uk/itm/Digital-Constant-Voltage-Current-Step-down-Programmable-Power-Supply-Module-H4DM-/141827383564?hash=item210592210c

 

 

[simmo39]

 

On 7/1/2016 at 20:00, nightvision said:

Some info that might be useful; I did a lot of testing recently to try and optimise TEC/Heatsink/Fan combinations.  The test camera in this case was an ASI120MM, I found that by dropping the TEC voltage (on 12706 and similar TECs) to around 7 volts I was able to reduce the fan size and speed and reduce heatsink size and achieve better cooling.  I didn't use PWM.   In this case I was cooling the whole camera casing, for cold finger arrangements I think I could go smaller/quieter.   The conclusion I came to was that most TECs when driven at max voltage are way too powerful for the job and generate more heat than the item to be cooled.  I used one of these to adjust the TEC supply: http://www.ebay.co.uk/itm/Digital-Constant-Voltage-Current-Step-down-Programmable-Power-Supply-Module-H4DM-/141827383564?hash=item210592210c

 

 

Hi nightvision, thanks for the pointer. may will invest in on if the tests go ok. Still thinking on how best to mount it to the camera. the elastic bands are not my best engineering solution!

[Jonk]

On 01/07/2016 at 20:00, nightvision said:

 ...In this case I was cooling the whole camera casing...

 

So strapping a heatsink / fan to a camera case without any mods made a noticeable difference to the file's cmos temperature reading?

[simmo39]

19 hours ago, Jonk said:

So strapping a heatsink / fan to a camera case without any mods made a noticeable difference to the file's cmos temperature reading?

Well im going to do some proper tests v soon but from a quick run the other day the case of the camera was noticeable cooler after 20 mins of running, so, im assuming ( a lot i know) that the camer insides will be cooled a little to. I know that its not as good as cold finger stuff but dont want to take the camera apart just yet. Even if its only a degree or two lower than ambient its got to be better right? hope so. Once I have worked out a propper test Ill post the results.

[simmo39]

Oh btw, still working on a better mounting than 2 rubber bands! 

[simmo39]

Ok, Did a first propper test of the set up and not sure If I can say it worked or not. Did 10 dark images of 1 min with and without cooler working    and     well they look the same to me, not sure how to measure the chip temp . anyway you can judge for yourself the images are below.

\no cooling.

Cooled for 30 mins before start and  running while taking darks.

Any thoughts?

[StuartJPP]

If you took the images in RAW format the temperature of the board (not necessarily the sensor) will be embedded in the file.

A tool like EXIFTool can extract the temperature under the field "Camera Temperature"...

 

[nightvision]

On 07/07/2016 at 22:18, Jonk said:

So strapping a heatsink / fan to a camera case without any mods made a noticeable difference to the file's cmos temperature reading?

Yes, using TEC/Heatsink/Fan, managed to drop on-chip readings by at least 21C, the sensor gets pretty warm when working hard, it heats up less at lower frame rates and longer exposures.  The ASI120 comes with 4 threaded holes ready to attach everything, condensation can become a problem, limiting the cooling helped.   Might try shrouding the camera with some insulation next.  

[simmo39]

16 hours ago, StuartJPP said:

If you took the images in RAW format the temperature of the board (not necessarily the sensor) will be embedded in the file.

A tool like EXIFTool can extract the temperature under the field "Camera Temperature"...

 

Hi, do you know where I can safely can download a copy? looked on the net and there seems a lot of dodge versions about. Btw, thanks for the pointer

[StuartJPP]

I have had a version for ages that I use...the official site is here:
http://owl.phy.queensu.ca/~phil/exiftool/

Also hosted on SourceForge...
https://sourceforge.net/projects/exiftool/files/?source=navbar

 

I sometimes also use EXIFToolGUI which is a GUI front-end for EXIFTool...
http://u88.n24.queensu.ca/~bogdan/

[simmo39]

1 hour ago, StuartJPP said:

I have had a version for ages that I use...the official site is here:
http://owl.phy.queensu.ca/~phil/exiftool/

Also hosted on SourceForge...
https://sourceforge.net/projects/exiftool/files/?source=navbar

 

I sometimes also use EXIFToolGUI which is a GUI front-end for EXIFTool...
http://u88.n24.queensu.ca/~bogdan/

Thanks, for that. Just put some of my darks i and here is some of the results.

No cooling.

1st dark       temp 18

Last dark     temp 25

 

Cooling running

1st dark     temp 19

last dark    temp 24

 

As can be seen the cooled run started at a higher temp than the uncooled but the last dark is cooler than the last uncooled dark. ( if you know what I mean ). so, my first results seem to show that it has worked ( I know early results yet ) but i will do more tests and stll need to work on the mounting!

[simmo39]

One thing i had not anticipated was how much currant the chip draws! my power supply is getting v hot!

[Stargazer33]

The peltier coolers can draw 6 amps - things will get hot! 

[Marci]

If you're getting internal condensation problems use DowCorning DC4 dielectric grease to cover any electronics at risk of getting wet, and to exposed edges of copper cold plate. S'how we handled water cooled 226w TECs back when I was overclocking processors & graphics cards. To limit all cooling to the TEC & heat sink, insulate external body with sticky-backed neoprene, however, if TEC fails it'll all then start to cook if you don't notice.

[simmo39]

18 hours ago, southerndiver357 said:

The peltier coolers can draw 6 amps - things will get hot! 

Think I will need a better power supply or at least run it off another power supply that wont effect my rig.

 

17 hours ago, Marci said:

If you're getting internal condensation problems use DowCorning DC4 dielectric grease to cover any electronics at risk of getting wet, and to exposed edges of copper cold plate. S'how we handled water cooled 226w TECs back when I was overclocking processors & graphics cards. To limit all cooling to the TEC & heat sink, insulate external body with sticky-backed neoprene, however, if TEC fails it'll all then start to cook if you don't notice.

I have not noticed any condensation yet but then I have only run it for about just over an hour. The cooking thing is something I want to avoid! 

[simmo39]

Just a quick follow up on the cooler mod. I have been out and tried the cooler a few times now. Here are a few thoughts and results. On my last outing I did 12 x 6 min subs. The first 4 subs averaged at 20 c the next 4 averaged at 25 c but when my battery pack went flat for the last 4 subs so no cooling temp shot up to 29 c . So hen fitted and working the cooler is cooling the internal of the camera not by a lot but every little helps, right. The main problem is power drain. I daren`t use my mains power supply as I dont think it would hack the cooler, mount and camera, so at the moment its a car battery power pack but even that gives up after about 8 six min subs! Still working on the mounting, the elastic bands seem to do the job but do look a bit blah.