DIY peltier on asi178mm

[CCD-Freak]

What are you doing about condensation when the camera gets down to the dew point?  Trying to seal the housing, connector openings etc can be a real pain. 

John Love
CCD-Freak
WD5IKX

[Fieldsy]

1 hour ago, Gina said:

Haven't considered running a Peltier TEC off a battery (other than something like a car/caravan battery).  I have cooled the astro camera in my ASC - an ASI178MC, using a good quality Peltier TEC - Peltier Module, 54.6W, 4.4A, 20V, 40 x 40mm.  Running this off my 13.8v main observatory supply and using water cooling of the hot side, I can get the camera temperature down to -12°C with an ambient temperature of 15°C.  The TEC draws around 2.5A.

Yeah looks like I'm resorting to a 12v 3 amp plug ,using a small fan trying to keep the weight down as dont want to start tilting ,haven't connected controler yet not sure where to put sensor probe .

[Fieldsy]

1 hour ago, CCD-Freak said:

What are you doing about condensation when the camera gets down to the dew point?  Trying to seal the housing, connector openings etc can be a real pain. 

John Love
CCD-Freak
WD5IKX

Wheres the camera ? I'm trying to get around 2 degrees .

 

Edited May 27, 2020 by Fieldsy

[CCD-Freak]

5 hours ago, Fieldsy said:

Wheres the camera ? I'm trying to get around 2 degrees .

 

So you are trying to cool it just enough to regulate the temperature to make calibration easier? 

I was re-packaging a Meade DSI-pro II to provide regulated set point cooling.  The finished camera cooled to 35°C below ambient air temp.  I usually ran the camera at -15°C
Sealing the camera to prevent condensation on the sensor was a bit difficult but I did get it to work.

 

John Love
CCD-Freak
WD5IKX

M27 Single 600 second sub at -15°C

Edited May 27, 2020 by CCD-Freak

[Fieldsy]

27 minutes ago, CCD-Freak said:

So you are trying to cool it just enough to regulate the temperature to make calibration easier? 

I was re-packaging a Meade DSI-pro II to provide regulated set point cooling.  The finished camera cooled to 35°C below ambient air temp.  I usually ran the camera at -15°C
Sealing the camera to prevent condensation on the sensor was a bit difficult but I did get it to work.

 

John Love
CCD-Freak
WD5IKX

M27 Single 600 second sub at -15°C

Yeah I dont want to have worry about condensation , I have rewired to take my 12v plug so will see how it handles it without sensor atm although i do have one if required . With my eq5 pro mount anything over 120 sec subs produces egg shaped stars and with the small pixel 178mm its prob never going to get any better .

[Fieldsy]

Hi so the 12v as working but I dont think the sink and fan can get rid of heat quick enough it is blowing heat but camera temp not cooling , so new bigger sink and combined fan turning up tomorrow .

[CCD-Freak]

Yeah...Finding a heat sink that can efficiently remove the heat can be a problem.  I tried multiple heat sink and fan combos before I ended up with the one I used on the DSI-Pro-II TEC project.  Did you use heat transfer compound between the TEC module and the heat sink and camera body?  If not you will not be able to efficiently transfer the heat.  Also a gap between the fan and the heat sink can improve efficiency. 

John Love
CCD-Freak
WD5IKX

[Adam J]

38 minutes ago, Fieldsy said:

Hi so the 12v as working but I dont think the sink and fan can get rid of heat quick enough it is blowing heat but camera temp not cooling , so new bigger sink and combined fan turning up tomorrow .

Water block and trickle feed is the answer lol. Stop messing about with fans and ill litterally give you a water block and connectors lol.

 

Edited May 28, 2020 by Adam J

[CCD-Freak]

Water is more efficient but the plumbing is more problem.  The heat sink I use actually uses convective circulation of oil to improve the heat sink efficiency.  I was able to get a solid delta T of 35°C without water.  If I wanted to get really cold I would use a two or three stage TEC with water cooling.  When you get really cold there comes a point of diminishing returns.   Most of the new cameras are low noise before cooling so going really cold is not really necessary.  A steady repeatable temperature makes calibration easier.

You probably already know this stuff.  🙂

 

John Love
CCD-Freak
WD5IKX