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Can someone please recommend a good 80mm fan for a dob?

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#1 Ihtegla Sar

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Posted 25 April 2019 - 11:25 PM

So I am trying to install an 80mm fan to the bottom of my new dob and the one I bought won't work. The wires weren't colored. They were all black so i had to guess which one was the positive wire, but when I tried to connect them to a battery the fan wouldn't spin. I think I connected them wrong since the fan has a faint burning smell now. And no matter what combination of battery terminals I connect to the wires, the fan won't spin. I didnt know you could burn up a fan so easily. Luckily the fan was cheap but now I need to get another one.

It would be a big help if someone could kindly recommend a good fan for the bottom of a dob that has colored wires so I can make sure to hook up the right wires to the right battery connections. Thanks!

#2 havasman

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Posted 25 April 2019 - 11:38 PM

I have 40mm and (2) 120mm Noctua fans in use and recommend them. There are many options from which to choose on their website including sizes, mounts and fans that take in-line resistors for speed selection if you want that. Noctua are good choices. Polarity discrimination for models is indicated in the very good documentation in the box and i think also on the website. Quiet with high head pressures.


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#3 Ihtegla Sar

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Posted 25 April 2019 - 11:59 PM

Thanks. Documentation would be great. That fan I bought had none. Noctua is the brand I used for a cooler when I built my PC. But that didn't involve jury rigging batteries to a fan, so I didn't burn anything out on my PC. I will see what they have in the 80 mm range.

Edited by Ihtegla Sar, 26 April 2019 - 12:06 AM.

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#4 Kunama

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Posted 26 April 2019 - 12:07 AM

I have 40mm and (2) 120mm Noctua fans in use and recommend them. There are many options from which to choose on their website including sizes, mounts and fans that take in-line resistors for speed selection if you want that. Noctua are good choices. Polarity discrimination for models is indicated in the very good documentation in the box and i think also on the website. Quiet with high head pressures.

Great fans, smooth, quiet and reliable....

 

https://noctua.at/en...m/specification


Edited by Kunama, 26 April 2019 - 12:09 AM.

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#5 Ihtegla Sar

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Posted 26 April 2019 - 12:23 AM

Great fans, smooth, quiet and reliable....

https://noctua.at/en...m/specification


Do you recommend the 4 pin over the 3 pin? Or does it matter?

#6 havasman

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Posted 26 April 2019 - 12:43 AM

I think I bought the 3-pin. But I took the connectors apart and wired them up to 12Vdc leads from the scope wiring harness.



#7 Ihtegla Sar

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Posted 26 April 2019 - 12:57 AM

Thanks. I think I will go for the three pin since there are fewer wires for me to screw up and I only need two wires to connect to a battery -- my scope doesnt have any electronics. For my first fan, I just want it to run and I can worry about variable speed later. The battery holder I've got has an on/off switch.

#8 Kunama

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Posted 26 April 2019 - 02:24 AM

I also bought the three pin one but cut off the plug and wired it directly.  

My fan is the 120mm NF-S12A Chromax.



#9 skywolf856

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Posted 28 April 2019 - 09:18 PM

I bought (2) 92mm Noctua Redux for my 18" Obsession Classic



#10 obsession18

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Posted 30 April 2019 - 07:59 PM

I installed a Vantec Tornado on my 18" Classic Obsession, they are meant to be used on servers, the thing moves a crazy amount of air, quite loud but really effective at cooling the mirror.



#11 Pinbout

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Posted 30 April 2019 - 08:32 PM

Here’s some fans I use- controller and battery

 

https://youtu.be/F9tvrBPSORk




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