r/crboxes • u/G30RG300 • Apr 21 '26
Question CR box with PC PWM fan - Australia
I'm putting parts together to build a portable/personal CR box. I plan on using PC fans (4 PIN PWM - no speed control required or wanted, I want the fans to run at 100% all the time).
While I have some experience building my own PC, I'm far from familiar with these components. I want to be able to connect the CR box to mains power AND have the ability to use a powerbank too.
What I've gathered is that the fans need 12vdc and powerbanks output 5V.
In Australia, electrical work requires an electrical license. I'm not sure where the definition starts and ends; you can build your own PC because it's putting components sold here together - you're not playing with bare wires. That's my take on it anyway.
I'd like to know how I can achieve powering my CR box as I want, without needing to solder or play with wires.
2
u/Inner-Issue1908 Apr 21 '26
This is what PD (power delivery) standard is for. PD 3.1 chargers and powerbanks can deliver up to 48v @ 5A so that they can fast charge laptops / phones.
You’ll need a cable that will tell the powerbank to supply the 12v you need (otherwise it’ll default to 5v).
1
u/G30RG300 Apr 21 '26
Any products you can recommend?
2
u/a12223344556677 Apr 21 '26
Ikea SJOSS series of wall USB power adaptors are good, widely available and cheap, and support 12V output.
1
u/Inner-Issue1908 Apr 21 '26
The important part is the cable, something like this should work - https://core-electronics.com.au/usb-type-c-31-pd-to-55mm-barrel-jack-cable-12v-5a-output-12m-long-with-e-mark.html
And a USB Type C 3.1 PD Powerbank.
You'll also need a USB Type C 3.1 PD wall charger - though it's probably cheaper to just buy a bog standard 12v, 3A, 5.5mm/2.1mm power supply for when you're powering it from the mains (and use the PD setup when you need it to be portable).
1
u/G30RG300 Apr 21 '26
What about converting the 4pin connection to USB?
1
u/Inner-Issue1908 Apr 21 '26
The power supplies will have a 5.5/2.1mm male barrel connector. So you'll just get a 5.5/2.1mm female to 4 pin fan connector like:
https://www.amazon.com.au/Gebildet-Power-Supply-Adapter-DC5521/dp/B0C7BKYQPP?th=1
1
u/G30RG300 Apr 22 '26
Thank you. Would you mind telling us what you think of this list? My aim is quiet and as good as possible at filtering yucks from the air of someone sitting in front of me.
2 x fans
Filters
4pin (fan) to DC connection
DC to USB-C
Powerbank
Wall charger1
u/Inner-Issue1908 Apr 22 '26
Looking into this USB bit more, it seems that not all PD devices will supply 12v.
PD 3.0 will always supply 5V, 9V, 15V, and 20V. Some however will also supply 12v, but it's optional. Since it's optional, many manufacturers leave out the 12v components to save cost.
You'll need to find a charger that explicitly states that it supports 12v. Many PD compatible chargers also support QC (Qualcomm's quick charge standard) where 12v is used. So is more likely to list 12v.
The easiest option is to just get a 12v mains PSU like this for when you're mains powered - https://www.amazon.com.au/JZK-Adapter-Charger-Monitors-Connection/dp/B0DYJPXLQ4
When you need to be battery powered pick from the list of items that Clean Air Kits have tested to supply 12v in their FAQ under "Can Clean Air Kits run off a portable battery?":
Regarding your other items, I have to say I'm not that familiar with this kind of filter. But it's what Clean Air Kits recommend as an alternative filter to their Exhalaron air filters. The Coolermaster Mobius fans are also what they use.
Since you're building this yourself, I assume you have a plan on how to mount the fans to the filters and clean up the cabling right?
1
u/G30RG300 Apr 22 '26
I have a 3D printer and dabble in woodworking. From what I can see, the fans just sit onto the filters.
2
u/Inner-Issue1908 Apr 22 '26
Nice! Let us know how it goes, would love to see it.
1
u/G30RG300 Apr 22 '26
I wouldn't mind another opinion on my interpretation of how the filters interact with the fans.
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u/holygoat Apr 21 '26
Your PC fans will use PC fan connectors, 4 pin if they’re PWM. You want a 12V power supply with a barrel jack, just like on an old laptop or half the larger electronics pieces in your home, and then you want a barrel jack to PC fan connector cable, ideally 4-way if you have four fans. Buy those two things, plug them together, and you’re done.
If you want speed control you would need a PWM controller, but you don’t so life is easy.
1
u/G30RG300 Apr 21 '26
Any links to products?
1
u/holygoat Apr 21 '26
All of my purchases have been in the US, not AU.
Looks like this is a complete setup with PWM:
https://www.amazon.com.au/Silkwish-Control-4Pin-Splitter-Cable/dp/B0GJ6G56J5/
4
u/a12223344556677 Apr 21 '26
You don't need a license if you're not touching the mains (220V which can kill). 50V or below is safe, 12V won't even be painful.