PSU for very low power pc: picoPSU or normal AC/DC?

PSUs: The source of DC power for all components in the PC & often a big noise source.

Moderators: NeilBlanchard, Ralf Hutter, sthayashi, Lawrence Lee, Devonavar

Post Reply
iacchi
Posts: 6
Joined: Sat Mar 10, 2018 4:09 am

PSU for very low power pc: picoPSU or normal AC/DC?

Post by iacchi » Sat Mar 10, 2018 7:32 am

Hello everyone,
this is my first post; I've done some searching around in the forum but I haven't found anything relevant that is recent and can help me with my decision.

I'm building a low-power system to act as a NAS and media center combined. It will stay on 24/7 and I will use it to store data, make backups, run media center (kodi) and some server (torrent, amule, web server with nextcloud, plex or the like). This is the hardware I have in mind:

Case: Cooler Master Elite 110 (bought)
MoBo: ASRock J4205-ITX
RAM: DDR3L 16 GB (not sure which one yet, considering that the MoBo is quite picky)
SSD: Kingston A400 120 GB (bought) for the OS
HDD: 2 x HGST DeskStar NAS 10 TB (bought) for data storage
PSU: ???

Power consumption wise, there is a nice review of a guy who has a configuration almost identical to mine (minus the two HDDs): https://essential-blog.com/2017/03/10/p ... itx-linux/ and he says that the system (he went for a picoPSU) uses about 8.6 W when idle and 17.2 W at full load. A sample compressed rsync backup operation takes 9.6 W. HGST supplies power consumption of the HDD only in idle mode (which would make 10.2 W for the two HDDs in my system) and looking at specs of similar hardware (WD gold 10 TB) the power consumption at full read/write is about 14.2 W for the two drives. This would make an idle total power consumption of 8.6 + 10.2 = 18.8 W and a full load power consumption of 17.2 + 14.2 = 31.4 W. Considering that I will run several programs in background all the time on the system, I can expect an average power consumption (when I'm not actively using it) of the system of about 25 W maybe?

Now for the question: given these hardware specs, power consumptions and the fact that it has to stay on 24/7, which PSU should I put on the system? The case itself has a normal ATX bay for the PSU but for the time being let's say I can put or build an adapter in there and that I don't care about the size, provided that none of the dimensions are bigger than the ATX one. Should I go with a picoPSU or with a normal AC/DC power supply? I still haven't managed to figure out how efficient picoPSU are, despite the fact that I've tried to read a lot about them. On the other hand, normal PSUs supply much more power than I require and even a low power PSU (say, 250 W) will only work on average at 10% of its capacity and at that load even 80+ Gold PSUs are not that efficient (provided that they exist).

At the moment, these are the best options that I've found:
picoPSU 80 W with 60 W power brick: http://www.mini-pc.se/index.php?route=p ... duct_id=70 (I live in Sweden)
normal PSU 250 W: https://www.inter-tech.de/en/products/p ... -mfatx25p8
normal PSU 150 W: https://www.ebay.it/itm/Fortron-Flex-AT ... 2099605811 (likely very good but it's starting to be quite expensive)
This as well is a bit expensive: https://www.amazon.de/Fortron-Flex-ATX- ... B01LY5S9SK
60 W power brick: https://www.meanwell-web.com/en-gb/ac-d ... a--60e--12 claims up to 88% efficiency

I'm well open to suggestions, be it a normal PSU or a more efficient power brick for the picoPSU (or a different picoPSU). The only limiting factor for me is that it should be sold in Europe. Of course price matters, but since it's staying on 24/7 I would like something energy efficient (and reliable).

CA_Steve
Moderator
Posts: 7650
Joined: Thu Oct 06, 2005 4:36 am
Location: St. Louis, MO

Re: PSU for very low power pc: picoPSU or normal AC/DC?

Post by CA_Steve » Sat Mar 10, 2018 11:45 am

Welcome to SPCR.

Efficiencies at very low power levels for ATX style PSUs are all fairly close (unless you look at some of the newer Titanium specs). Figure the absolute best idle with 5-6W of power loss (Gold+) and the middle of the road stuff is in the 9-10W range of power loss (bronze). The percentages may be drastically different, but the actual wattage of power lost to heat isn't that big. You can get better efficiency out of a brick + DC/DC combos. But, the devil is in the details. EU currently requires Level V for bricks and voluntary requirements for Level VI. The DC-DC side should be in the 95% range.

picoPSU 80 W with 60 W power brick: no efficiency ratings listed...but being sold in EU...so should be Level V for brick. You could ask the vendor.

I'd stay away from the tiny fanned PSUs unless you can find an rpm profile...

iacchi
Posts: 6
Joined: Sat Mar 10, 2018 4:09 am

Re: PSU for very low power pc: picoPSU or normal AC/DC?

Post by iacchi » Sat Mar 10, 2018 5:06 pm

Thank you for your reply. I will read a bit more about these levels and on Monday I will contact the shop.

iacchi
Posts: 6
Joined: Sat Mar 10, 2018 4:09 am

Re: PSU for very low power pc: picoPSU or normal AC/DC?

Post by iacchi » Sat Mar 10, 2018 5:25 pm

Sorry for the double post, but the previous one is still in moderation. Feel free to merge them.

A deeper search on the shop website yielded the power brick model: it's a Seasonic SSA-0651-1, here the specs they link: http://www.mini-pc.se/pdf/SSA-0651.pdf
If I well understand the page you linked me before, it's a level IV, although an efficiency of 85% is not too bad.

iacchi
Posts: 6
Joined: Sat Mar 10, 2018 4:09 am

Re: PSU for very low power pc: picoPSU or normal AC/DC?

Post by iacchi » Sun Mar 11, 2018 5:23 am

Last question, then I'll let someone approve my posts :P

Searching for a level VI power brick I've stumbled upon this one: https://www.amazon.co.uk/Synology-Adapt ... 01HO1HYVA/ which I've found on Amazon IT for about 26 euro. I haven't been able to find full specs online, but it says everywhere (not only on Amazon) that it's a level VI on the title of its listing, so it must be, right?

CA_Steve
Moderator
Posts: 7650
Joined: Thu Oct 06, 2005 4:36 am
Location: St. Louis, MO

Re: PSU for very low power pc: picoPSU or normal AC/DC?

Post by CA_Steve » Sun Mar 11, 2018 9:24 am

For grins, I built a little spreadsheet to compare brick efficiency levels. It's more useful to compare power loss vs power level for an A-B comparison.

As for the Synology brick, it doesn't mention the output voltage or what plug is used...you might look at laptop (like Dell) bricks.
You do not have the required permissions to view the files attached to this post.

iacchi
Posts: 6
Joined: Sat Mar 10, 2018 4:09 am

Re: PSU for very low power pc: picoPSU or normal AC/DC?

Post by iacchi » Sun Mar 11, 2018 10:32 am

Thanks again for your reply. The table is quite useful and I guess that at 60W the difference will be even more relevant, so it's really better to go for a level VI over the level IV. About the Synology brick you're right, it doesn't say which voltage it outputs. Looking at reviews online of Synology NASes listed in the compatibility list in the title, I've found this sentence: "but also power leakage in the systems in-line transformer which drops the voltage down to 12V from 110-240V (depending on your region)" so I guess the voltage at least is right. I don't think it comes with a power plug, I will probably have to buy it separatedly. I'll continue having a look at power bricks but the efficiency level is almost never stated, which makes it hard to make a choice... What about this one? https://www.mouser.se/ProductDetail/Adv ... mgPg%3d%3d
Last edited by iacchi on Sun Mar 11, 2018 11:02 am, edited 1 time in total.

Abula
Posts: 3662
Joined: Tue Nov 02, 2004 12:22 pm
Location: Guatemala

Re: PSU for very low power pc: picoPSU or normal AC/DC?

Post by Abula » Sun Mar 11, 2018 11:01 am

Meanwell imo is of the best power supplies manufactures worldwide, but one thing you do need to find out is not the watts but the amps max amps your setup will draw, most of the picoPSU just do a pass through on 12V, the smaller the brick the less amps it will have, so just be sure that you will cover the peak amps.

A couple of bricks that you should check are,
MEAN WELL GS40A12-P1J 12V 3.33 Amp 40 Watt Power Supply
MEAN WELL GS60A12-P1J 12V 5 Amp 60 Watt Power Supply

Btw as comment, i have ran my camera server on picoPSU150XT + 150W brick (it was a combo from minITX) for 3 years no issues at all.

iacchi
Posts: 6
Joined: Sat Mar 10, 2018 4:09 am

Re: PSU for very low power pc: picoPSU or normal AC/DC?

Post by iacchi » Sun Mar 11, 2018 11:08 am

Hi, and thank you for your suggestions. I already stated in the first post that the system is likely to use about 32W maximum under full load, so the number of ampere is already there. I'm still going to get a 60W brick and not a 40W one to stay on the safe side and allow for the growth of the system in the future if needed. I had a look at the Mean Well brick you suggested, which has apparently been superseeded by model GST60A12-P1J (or so mouser tells me), but the problem is that it has a 2.1 mm plug, while the picoPSU has a 2.5 mm one. I could get an adapter, but I would rather not do so.

CA_Steve
Moderator
Posts: 7650
Joined: Thu Oct 06, 2005 4:36 am
Location: St. Louis, MO

Re: PSU for very low power pc: picoPSU or normal AC/DC?

Post by CA_Steve » Sun Mar 11, 2018 11:22 am

The Advantech looks ok.

Abula
Posts: 3662
Joined: Tue Nov 02, 2004 12:22 pm
Location: Guatemala

Re: PSU for very low power pc: picoPSU or normal AC/DC?

Post by Abula » Sun Mar 11, 2018 11:43 am

iacchi wrote:Hi, and thank you for your suggestions. I already stated in the first post that the system is likely to use about 32W maximum under full load, so the number of ampere is already there. I'm still going to get a 60W brick and not a 40W one to stay on the safe side and allow for the growth of the system in the future if needed. I had a look at the Mean Well brick you suggested, which has apparently been superseeded by model GST60A12-P1J (or so mouser tells me), but the problem is that it has a 2.1 mm plug, while the picoPSU has a 2.5 mm one. I could get an adapter, but I would rather not do so.
If you need a 2.5 barrel dont mind going into 80W, then consider

MEAN WELL GS90A12-P1M 3-Wire Regulated AC-to-DC Switching Table-Top Power Supply, 12V, 6.67 Amp, 80W, 1.5"

Thats the PSU i used on my download stations with a picoPSU 90XLP, here is a pic, i was able to drop around 10W on i3 2100T on intel motherboard.

Image

Post Reply