Peltier Cooling fan query

[Tomatobro]

Putting some insulation round the camera body will improve the cooling and stop the external condensation.

ZWO do some circular stick on heaters which will help with the window fogging. Flo list them I think

 

ZWO Anti-dew heater strip for ASI cooled cameras

Edited October 9, 2020 by Tomatobro
update

[Bobby1970]

Not 100% sure the Zwo dew strip will fit the 178mc. 

I wonder, would a camera lens dew heater, wrapped around the part of the focusser where the nosepiece of the camera inserts, work maybe? 

Ultimately the front part of the camera needs to be kept a bit "warmer" than the rest of the camera, right? Or have I got this all wrong?

 

[tomato]

I can confirm that the ZWO heater fits the ASI 178 mono.

https://www.firstlightoptics.com/zwo-accessories/zwo-anti-dew-heater-strip-for-asi-cooled-cameras.html
 

As the non cooled cameras aren’t designed with forced cooling in mind, they can be prone to  ice crystals and water droplets. I recommend not taking the temp sub zero but rather keeping it stable at 2-3 degrees, thereby ensuring consistent application of calibration frames.

[Bobby1970]

28 minutes ago, tomato said:

I can confirm that the ZWO heater fits the ASI 178 mono.

https://www.firstlightoptics.com/zwo-accessories/zwo-anti-dew-heater-strip-for-asi-cooled-cameras.html
 

As the non cooled cameras aren’t designed with forced cooling in mind, they can be prone to  ice crystals and water droplets. I recommend not taking the temp sub zero but rather keeping it stable at 2-3 degrees, thereby ensuring consistent application of calibration frames.

That is awesome news, many thanks for confirming, i was about to start cutting out circular bits of paper/card to check if it would work lol.

I have no intention of running it sub zero, i don't think it will get there anyway tbh, seems to level off at around 3-4 deg.

Just need some suitable insulation to make a jacket for it now.

Thanks again

[Tomatobro]

Re the temperature drop question,  in a warm room at say 20c and bench testing shows a sensor temperature of 5 c means that outside in the cold air it will go down to around -8c unless some form of control is introduced.

[Bobby1970]

3 minutes ago, Tomatobro said:

Re the temperature drop question,  in a warm room at say 20c and bench testing shows a sensor temperature of 5 c means that outside in the cold air it will go down to around -8c unless some form of control is introduced.

when i bench tested it yesterday, it was in my cool garage, probably around 12-14 deg.

I do appreciate what you are saying and if needed will introduce some sort of temp control to the system.

Edited October 10, 2020 by Bobby1970

[Tomatobro]

I use these modules a lot from Ebay

 

193288386461

Under a fiver

Even comes in a self assembly clear case

Edited October 10, 2020 by Tomatobro
update

[Bobby1970]

12 minutes ago, Tomatobro said:

I use these modules a lot from Ebay

 

193288386461

Under a fiver

Even comes in a self assembly clear case

Thats a bargain. 

does it require a sensor adding to the case of the camera/peltier? Or does it just measure ambient??

Thanks again

[Tomatobro]

comes with a remote sensor. The relay is rated at 10 amps and comes with a set of instructions on set up options.

Power up and relay closes. Set the turn off temperature and the hysteresis level i.e open at 3 c close at 5 c

Edited October 10, 2020 by Tomatobro
info added

[Bobby1970]

3 minutes ago, Tomatobro said:

comes with a remote sensor. The relay is rated at 10 amps and comes with a set of instructions on set up options.

Is it best to sandwich the remote sensor on the cold side of the Peltier?

Or just somewhere on the case of the camera??

Thanks again, all good info and an exciting DIY project

[Tomatobro]

If you lag the camera body then tuck the sensor next to the camera body underneath the insulation. Use sharpcap to monitor the sensor temperature and adjust the on/off controller temperature till it gives you what you want. These temperature settings will be different to what sharpcap says but once set will give good results.

Takes about a hour and a half of bench time to optimise the settings

You can cut the sensor wire length to suit as its about half a metre long as I recall

Edited October 10, 2020 by Tomatobro

[Bobby1970]

1 minute ago, Tomatobro said:

If you lag the camera body then tuck the sensor next to the camera body underneath the insulation. Use sharpcap to monitor the sensor temperature and adjust the on/off controller temperature till it gives you what you want. These temperature settings will be different to what sharpcap says but once set will give good results.

Takes about a hour and a half of bench time to optimise the settings

Excellent, thanks so much for the info.  if i can get the thing to a steady 3-4deg regardless of the ambient and also stop the sensor window fogging up i will be more than happy.

Thanks again

[Tomatobro]

your welcome.  I dispensed with the heater and just set the sensor temperature to 3 c. Although you can hear the relay clicking is does not affect the stability of the image.

[Juicy6]

20 hours ago, Bobby1970 said:

Anyway I left it running for 10-15mins. Temp down to 3.5 degrees. So pretty good I think. 

And what was the temp difference when you pushed vs pulled air over heatsink? You asked the question and you can tell us!

Christer, Sweden

[Juicy6]

20 hours ago, Bobby1970 said:

Anyway I left it running for 10-15mins. Temp down to 3.5 degrees. So pretty good I think. 

And what was the temp difference when you pushed vs pulled air over heatsink? You asked the question and you can tell us!

Christer, Sweden

[Bobby1970]

4 minutes ago, Juicy6 said:

And what was the temp difference when you pushed vs pulled air over heatsink? You asked the question and you can tell us!

Christer, Sweden

I haven't tried swapping the fan around yet, i currently have it drawing ambient air onto the heatsink. 

[Neil H]

Is it dewing up because the air is being blown into the camera so sensor  face is getting very cold  . Would it do this if the air was being pulled from inside to outside may be sensor would not get as cold so the battle begins 

Heat one side cool the other ???

[Bobby1970]

1 minute ago, Neil H said:

Is it dewing up because the air is being blown into the camera so sensor  face is getting very cold  . Would it do this if the air was being pulled from inside to outside may be sensor would not get as cold so the battle begins 

Heat one side cool the other ???

thats certainly worth exploring. I have a dew heater wining its way to me so will be working more on the cooler during the week i would think.

 

[Bobby1970]

So, today I started with some insulation around the main part of the camera body and pit the camera on test for around ten mins. Insulation around the main body seemed to do a good job, need to make some smaller bits for around the rest of the camera and heatsink/peltier as there was still moisture there. Sensor window still fogged up temp 3-4 Deg after 10 mins or so. 

Next I reversed the fan so it was pulling air from the heatsink and out into the ambient air. Within 10 mins the temperature had gone from an initial 20 odd Deg. Down to sub zero. 😨. There was actually frost on the rear of the camera lol. It leveled off at around -0.2-03 Deg. Sensor window still fogged up. 

My current conclusion is. 1) I still need some sort of dew heater for the front of the cam. 2) I will deffo need some temp control lol. And 3) the fan may be too loud. Lol. 

 

Edited October 11, 2020 by Bobby1970

[Adam J]

You dont really need to go sub zero and it will solve a few issues if you dont.

Adam

[Bobby1970]

7 minutes ago, Adam J said:

You dont really need to go sub zero and it will solve a few issues if you dont.

Adam

I am wondering if I can run it without the fan. Need to do some more testing. See how it goes without it. 

Made some more of the foam insulating jacket. 

Had some thin self adhesive black foam left over from something so.covered the insulation around the main body with that too. 

 

[vlaiv]

7 minutes ago, Bobby1970 said:

I am wondering if I can run it without the fan. Need to do some more testing. See how it goes without it. 

I would not recommend that - there is a chance of burning Peltier element - you really need to remove heat from hot side, otherwise, sensor will remain warm and aluminum part will get extremely hot - there will be temperature difference but if you don't dissipate that heat effectively it will build up and even damage your elements.

[Adam J]

26 minutes ago, Bobby1970 said:

I am wondering if I can run it without the fan. Need to do some more testing. See how it goes without it. 

Made some more of the foam insulating jacket. 

Had some thin self adhesive black foam left over from something so.covered the insulation around the main body with that too.

 

Dont run without the fan, you might be able to reduce fan RPM if you also reduce the voltage to the peltier.

When I did this I actually used a water block and trickled water through it.

Adam

[Bobby1970]

Noted on the "no fan" idea. 

Thanks guys. 

I could stick a variable resistor in line with the fan I guess and reduce the speed to an acceptable noise level maybe, while still cooling the heatsink. 

I just wondered if the fact that the heatsink is 40x40x20mm, it may have been enough without the fan. 

I'm just making it up as I go tbh. Lol

 

Edited October 11, 2020 by Bobby1970

[Adam J]

9 minutes ago, Bobby1970 said:

Noted on the "no fan" idea. 

Thanks guys. 

I could stick a variable resistor in line with the fan I guess and reduce the speed to an acceptable noise level maybe, while still cooling the heatsink. 

I just wondered if the fact that the heatsink is 40x40x20mm, it may have been enough without the fan. 

I'm just making it up as I go tbh. Lol

 

You need a fan with a magnetic breaing / low noise as if its making lots of noise then its certainly causing vibrations to the sensor.

Adam