Peltier Cooler for Canon DSLR

[Steve 1962]

I'm sat here watching the temperature drop on my new 1000d having just finished making a peltier colling chamber for it .

I followed Gary Honis's instructions;

Peltier Cooling of Modified Canon Digital Rebel XSi (450D) - Version III -by Gary Honis

almost to letter except that I sourced all of the components individually from the UK and I used nylon bolts to hold the peltier unit and heat sinks onto the case in order to reduce the thermal paths out of the chamber.

Initial tests show that it'll cool the camera by about 20c or 36f in about an hour...and it cost less than £20 for the bits.

The Peltier Unit is a 60W 40x40mm unit from eBay (£3.98 inc postage), the internal heatsink is exactly the same as Gary uses (£9.62 from Amazon Marketplace), the external heatsink was blagged from a local computer repair shop - Future Resources in Taunton - for free - THANKS ROD! "You want it for what....?". I used 1.25mm aluminium sheet (about a fiver from a local engineering company) and that's it....except a few hand tools and some help from Jake at work - THANKS JAKE! Oh, and some waste polystyrene packing.

Weight is about 600g, so we'll see how my mount and focuser handles it later in the week

If anyone's interested , I'll post more details and photos later

Steve

[Mick UK]

This might sound a daft question, but how do you see what your trying to image with your Canon to achieve focus etc, other than a hole for the sensor to see through, it looks like a sealed box?

Looking at some of the images from the link taken at 1600iso id say your definitely on to a winner here with this cooler. (assuming the extra weight is not to much to cope with)

I'd Love to see more info and pics if you dont mind Steve:)

edit:

One question though......do you leave the fan running constantly and if so, wont this create camera shake?

[George]

Im doing the cold finger mod, Ive already made the coldfinger out of some 1.2mm thick copper sheet (purchased off ebay) and attached a heatsink and fan.

This mornings test in the obsy at a ambient temperature of 32C I was getting a 16C reading on the cold finger, in a enclosed space ie the canon Id expect that to drop quite a bit more maybe double, getting a lot of condensation on the attachment plate but the finger itself is bone dry.....which is good

Im waiting on some Artic Silver compound before I go any further, Im pretty sure this will make a further drop possible as the compound Im using at the moment is of dubious quality.

Looking good so far

[Psychobilly]

Good work guys :icon_salut:

I will follow this with interest

Peter...

[Steve 1962]

Hi again guys

Thanks for your interest.

Here's a shot of the empty chamber and then one with the cooler unit fitted. I think these show how closely I've followed Gary Honis's version and clearly show the holes for the flash gun nose peice and the T mount opening.

The external heatsink was used as a template to cut a plate for the internal heatsink and fan to be glued to, then the plate, the external heatsink and the chamber were drilled and the external heatsink was tapped to accept the 2BA nylon bolts that can be seen inside the box. The Peltier module is sandwiched between the external heatsink and the chamber the held in place with the 2BA nylon bolts.

A 4mm layer of foam double sided tape was fitted around the peltier unit and serves as insulation around the unit and between the warm external heat sink and the cold chamber.

Heat conducting paste was carefully applied on both sides of the peltier module, and on both sides of the internal heatsink plate to improve thermal conduction.

The cables for the heat sink and a temperature sensor (£2.75 from eBay inc postage!) were routed through a small grommet in a hole drilled in the side of the box below the external heat sink.

One note of caution to anyone thinking about building one of these - I've just taken the camera out of the finished insulated and sealed chamber after a couple of test runs (graph attached showing the temperature in the chamber in degrees c against time in minutes) and there was a fair bit of moisture inside even though I thought I'd done a good job of sealing the whole thing (the camera's dry though) so I'm going to have to work on the sealing and moisture control (Silica Gel??)before I go any further. I have a nagging feeling that the up turn at the end of the graph is caused by the condensation giving up its Latent Heat - how's that for a bit of GCSE Physics!? (read - Guesswork!).

I'm away all week now with work so I'll post some more photos towards the end of the week showing the completed chamber.

Moderators - I've just thought - should this be in the DIY section really? If so - please move - thanks.

TTFN

Steve

[joner]

Great job Steve.

Peltiers are great littlt gadgets to play with.

Heres a great guide for anybody intrested on peltier cooling (it's for pc's but the principles are universal),

Nols tec guide,

NoL's TEC Guide: Guide 1 Basic Principles of TEC's - Overclock.net - Overclocking.net

[George]

Today I lapped the heatsink and also the finger itself and managed a 21C drop from ambient that's a further drop of 5C from yesterdays 16C.

Observatory ambient was 22C, cold finger was 1C. With everything insulated and some Arctic Silver paste I'm confident of a -30C drop from ambient which hopefully would put a DSLR in the same dark noise league as a OSC CCD ie the QHY8.

The Canon 1000D already has a good low noise dark frame signature and I wouldn't be surprised if the peltier mod does away with the needs for dark frames........we shall see

[ncjunk]

They had an article on this in a spanish astro mag. They put the little silicon gel packs in to absob the moisture, i believe you then heat them up in the oven to dry them out again..i dont really know.

They basically created a copper box with insulation and cooled it with the peltier, the normal unmodified camera sat inside.

Basically the same as you are doing, i also saw another somewhere where they stripped the camera body off and added a cold finger....i prefer the looks of the camera intact!

[George]

Your probably thinking of this mod Hyper-Modification of Canon 450D (XSi) Cameras

Don't think Id have the balls togo that far

[ncjunk]

What power supply, voltage and ampage are you running these peltiers at?

I dont want to run too much current through one and wondered what you had.

Thanks

[George]

I'm running a converted PC power supply @ 12v

The Peltier pulls around 90W dunno what that is in amps.....probably around 3 or 4.

I'm getting a -32C drop from ambient which is cool ( excuse the pun )

[ncjunk]

Whats the current rating on that?

[George]

A max of 15v.

[Starflyer]

I'm hoping to have mine finished in a week or so and will report back here. I have the option of a 100w peltier or a 45w one if the former turns out to be too hard to cool, (or possibly 2 x 45w units stacked).

I have one question; all cpu heatsinks seem to be shiny aluminium / copper, I can't get my head around whether they would be more efficient if they were black. Am I wrong in thinking that if I sprayed it matt black (or had it anodised) it would would dissipate heat more effectively?

Cheers,

Ian

[George]

Your want the peltier to have perfect contact with the heatsink to absorb the heat, painting it matt black will make the surface contact less than flat. I placed some 1600 grit wet & dry on a flat steel surface and rubbed the heatsink until it had a mirror finish.

I have seen heatsinks painted black whether this has any effect probably only a thermal dynamics expert could tell you

[Starflyer]

I know the surfaces in contact should be as perfectly flat as possible. I used to muck around with watercooled pcs and still have a lapping kit around that I plan to use on the heatsink.

I was thinking more about the fins being black, in my mind they would radiate more efficiently. But as you say we need a thermal dynamics expert to say whether forced air is better over over black or natural finish fins. I guess paint could also act as a thin insulating layer, I have a friend who does black anodising but I may not be able to get it done in time for Salisbury.

[ncjunk]

Depends on the properties of the paint but i would hazard a guess that it would inhibit the heat transfer to air from the metal.