fanless design - PSU choice

[KzE]

Hello SFF Forum,

I am new here and just discovered the world of SFF PSUs.

If you don't mind, I would like to ask your help with this PC build:
https://www.digitec.ch/de/ShopList/Show?shopListId=56BB3D3649EFE326C8BA4ECD1E06E3F1
(haven't decided on the motherboard yet)

1
I have a very costum, passive water cooled design that needs to
be very flat. So I discovered these HDPLEX and PICO-BOX
things. But I just can't believe they actually power all that's
in my list. I have learnt that PSU really don't need to be that
powerfull, and the new CPUs and GPUs are very low in consumption,
but 250W only? Is it really possible? A guy on amazon claims
to run an OC i5@4.2Ghz with a GTX970 over a HDPLEX 250W..
My parts pull way less..

2
If not, could I use two of them and bring their power together
through a power combo thing like this?
http://www.phanteks.com/PH-PWCOB.html

3
I read somewhere they have a aluminium plate in the back
and can go higher if properly cooled. So if I let it touch my
water would that increase the power?

 

[Kmpkt]

1.) Yes you can certainly run a 970/1070 and CPU inside of 250W. The one thing you'll need to consider is there will be an additional draw on your power supply of around 20W for a medium sized pump like the DDC 3.2. I know that Josh with NFC has run a low power T model Intel CPU and a 970 around 220-230 with real-world gaming stresses. I think if you were to change your chip choice from a 6700K to a 6700T (or you can try under clocking if you want with the 6700K) and go with a 1060 you'd probably be able to water cool as well. If you go with a stock 6700K and/or the 1080 you've selected on your list you'll probably be pushing your power supply into the red zone further than you'd ideally want to.

2.) You could use theoretically that solution, but you're also going to need a pair of AC-DC bricks to power each of the HDPlex units separately. Also worth mentioning is that the Phanteks combo unit you've mentioned is pretty huge and I don't know of too many SFF cases that would accommodate one with two HDPlex DC-DC boards and all the extra cabling etc. required.

3.) Yes the HDPlex is mounted on an aluminum plate, but I'm not sure that it actually acts as a heatsink to transmit heat to the case. Dan has tested the HDPlex with air cooling across its heatsink however and has pushed the unit up to over 400W, so for the 250W range you shouldn't really need to worry as much about dissipation.

 

[KzE]

thank you for your answers.

1
I really would not want to downsize. I usually keep my PCs for very long, and want them to be fit for that.

2
I was thinking that two HDPLEX would definitely be sufficient and last a long time running with average intended power output.
The bricks wouldn't have to be the most powerful since now their load is shared. I could get smaller ones that together
are maybe as big as a 350W Voodoo.. plus I build my own case. A wallmounted PC, really all I need is something flat.
The phantek combo is flat so no problem there.
In the two other dimensions I am very free. If there were a fanless PSU flat but wide, I would take it. (see 4)

2.1
Could the HDPLEX 250W be powered by this?
http://www.hd-plex.com/HDPLEX-Internal-160W-AC-DC-Adapter-with-Active-PFC-and-19VDC-Output.html
I see the difference in Watts, but they have a "HDPLEX nanoATX 80W AC-DC+160W DC-ATX combo" which lets me assume there is something going on when going from AC to DC...?
I am really good mechanically, but electricity i still need to find out about

3
So I could connect the heatsink to the water loop and secure save operation of the HDPLEX then..?

4
What do you think about this PSU, two of them connected with a Phantek combo?
http://www.streacom.com/products/zf240-fanless-240w-zeroflex-psu/
It is made especially for passive cooling.. the black bracket is where it dissipates, could easily be connected to my water loop.

 

[Kmpkt]

1.) Fair enough. You could probably pull off a 1080 at stock and a lower wattage T-variant CPU with 250, but it might be tight as I'm not sure how aggressively the 1080 spikes its power demand.

2.) Rather than using two HDPlex, you could just look at the Pico Box X7-ATX-500 (http://www.aliexpress.com/store/pro...PIN-DC-ATX-Power-Supply/211500_747813627.html)

2.1.) Larry at HDPlex is releasing a 250W variant of the 160W AC-DC in the next month or so. It is the same length and height with an additional twelve millimetres in height. You could certainly combo 80+250, 160+250 or 250+250 through a load sharing adapter. You'd just need an DC-DC board that is capable of handling that input without encountering heat issues.

3. I think you'd need to at the very least have a custom water block done to consider water cooling the AC-DC supply. I don't even know if that would be advisable. I am under the impression that the 250W AC-DC will need some sort of forced air cooling and that the 160W version was designed at the upper limits for heat dissipation passively.

4.) The Streamcom is specifically designed to go into an aluminum case that effectively acts as a giant heat sink via the black bracket with the screw holes. If you wanted to build out your case to take care of this you may be able to get it to work. Also if you're looking to merge two power supplies, you could also look at the Add2PSU units which are much smaller and cheaper.

 

[KzE]

2
I have seen this product too. Do you think it is as reliable as the HDPLEX?
This certainly would be a practical solution...
How comes this one can handle so much but still be passive cooled?
At max load, forced air ventilation is required. For fanless or improper ventilation operation de-rate the output of the 3.3V, 5V and 12V rails until PSU temperature fails below 65C. Peak load should not exceed 60 seconds. Combined max power output should not exceed more than 550 watts.


They talk about "Dual 19.5VDC Power Adapter Inputs" but where are they?

I assume using two HDPLEX would solve the need for forced air since they
would not get as hot? Especially since the PICO-BOX seems to need two
bricks anyway...


2.1
Thank you for this info. I'll look into it.


3
costum waterblock is no problem. I have access to a cnc shop.
I would really like to avoid any fans. I have 6.5m2 of passive cooling surface
via aluminium heat sinks. The whole design bases on that, a fan would be odd.

4
I have seen the Add2PSU. Does it really distribute the power equally? It seems
the power shared goes through just the 24pin/4pin connector.
Looks super simple and small though.. would be great.