Tiny, Silent and Efficient: The picoPSU

ryboto · **Posted:** Thu Oct 04, 2007 11:15 am

redtyler1 wrote:

Hi all,

I am building a low power consumption XP MCE box. These are the components:
Case: GMC AVC-S7
Motherboard: Gigabyte GA-MA69GM-S2H (55w)
CPU: AM2 Athlon X2 BE-2350 (45w)
RAM: OCZ Platinum 2gb (?w)
DVD: notebook slot DVD player (5w)
Video Card: MSI 8600GT (45w)
Hard Drive: Seagate 5400rpn 2.5 80gb (5w)

I've tried to estimate the components' power usage, but i am not sure if I have them correct.

I was going to use either the picoPSU-120 or the PW-200-M, but I don't know enough about the differences between the two, is it just wattage?, and whether the system i am building would work with the power brick mechanism.

I routinely build systems, but have never done this before. I am considering dropping the vid card since this will be exclusively an htpc. No gaming at all.

Can someone help me out? Thank you very much.

Alex

If you drop the card, the Pico would have no trouble at all. If you keep it, and the motherboard really does draw that much under load, you might be on the thermal edge of the Pico's abilities. I say thermal, because it's power output is actually underrated.

Then again, if the 8600 uses less power than my x1950pro, if everything is stock, no OC, the Pico should handle it fine. The PW-200 is a good alternative, but it probably isn't necessary, especially if you drop the video card.

jaganath · **Posted:** Thu Oct 04, 2007 11:42 am

Quote:

Motherboard: Gigabyte GA-MA69GM-S2H (55w)

I suspect it is nearer to 20-25W. 55W is a huge amount for a motherboard to draw.

gudmann · **Joined:** Fri Sep 21, 2007 4:17 am **Posts:** 23

redtyler1 wrote:

Hi all,

I am building a low power consumption XP MCE box. These are the components:

Video Card: MSI 8600GT (45w)

I was going to use either the picoPSU-120 or the PW-200-M, but I don't know enough about the differences between the two, is it just wattage?, and whether the system i am building would work with the power brick mechanism.
Alex

Do you really need the card ? The motherboard has DVI, HDMI and a component backplate comes with it if you need that.

my best
Gudmann Bragi

VanWaGuy · **Posted:** Tue Oct 23, 2007 8:05 am

There were several mentions of concern using a pico-psu for car computer use.

The model reviewed could be a concern, but there are several models of pico psu, including several "WI" or "wide input" models. Some that work 12 and up to 25 or 26 volts, good for car use as long as the voltage does not sag during say starting, and there is even at least one version tht is 6-26 volts.

I believe that the least expensive models do just pass the 12 volts straight through, but not all of them.

Grant · **Joined:** Thu Nov 01, 2007 2:56 pm **Posts:** 1

The review comments favorably on all of the adapters included:

Quote:

To make up for the lack of cables sets, a number of
adapters are included so that different kinds of devices can be
connected. Most important of these is an adapter for the +12V
AUX plug found on nearly all mainstream motherboards. A 20-pin
to 24-pin adapter is also included,

As if.

Maybe reviewers get sent adapters, but regular customers don't
get them. I just bought the pico120 unit that was reviewed and
it certainly didn't come with any adapters. If I'd known that,
I could have ordered the adapters I needed. Now I've got to try
to kludge something together. :/

hmsrolst · **Posted:** Thu Nov 01, 2007 4:09 pm

You can get one here:
http://www.short-circuit.com/categories/cablespc.php

matt_garman · **Posted:** Fri Nov 02, 2007 4:31 am

Grant wrote:

The review comments favorably on all of the adapters included:

Quote:

To make up for the lack of cables sets, a number of adapters are included so that different kinds of devices can be connected. Most important of these is an adapter for the +12V AUX plug found on nearly all mainstream motherboards. A 20-pin to 24-pin adapter is also included,

As if.

Maybe reviewers get sent adapters, but regular customers don't get them. I just bought the pico120 unit that was reviewed and it certainly didn't come with any adapters. If I'd known that, I could have ordered the adapters I needed. Now I've got to try to kludge something together. :/

I made the same mistake (I've got basically the same post as you floating around here somewhere).

Mike, the wording in that review is a bit misleading: "To make up for the lack of cables sets, a number of adapters are included so that different kinds of devices can be connected. " (Emphasis mine.) I suggest: "To make up for the lack of cables sets, a number of adapters are available so that different kinds of devices can be connected."

ryboto · **Posted:** Fri Nov 02, 2007 5:31 am

well, it's not like short-circuit ever said they were sending me cables with the pico, i mean, the fact that they have two models, one with, one w/o a p4-4pin atx connector kinda suggests nothing else is included. If the product description doesn't say "additional cables included", then I'll assume it doesn't have any extras just because a review did.

tonyb · **Posted:** Tue Dec 04, 2007 3:08 pm

Is there an easy way to tell the PicoPSU-120 and PicoPSU-80 apart by looking at them?

srbliss · **Joined:** Thu Sep 22, 2005 9:55 am **Posts:** 64

Has anyone considered the 12V sag at high load may be caused by the fairly small gauge wires used between the brick and the Pico? I think the wire is 14g but I am not sure. 8A is a fair amount of current and 3-4 feet of smallish wire can cause a voltage drop.

|Romeo| · **Posted:** Tue Jan 20, 2009 11:58 am

srbliss wrote:

Has anyone considered the 12V sag at high load may be caused by the fairly small gauge wires used between the brick and the Pico? I think the wire is 14g but I am not sure. 8A is a fair amount of current and 3-4 feet of smallish wire can cause a voltage drop.

Assuming 14 gauge (AWG) wire and a wire length of 1m (so about 3 feet) the voltage drop would be 0.0663V. This; if you work it out, is just over half a percent (0.55 to be precise).

In ATX 2.2 the +12v rail has a 5% tolerance, so you are safe by an order of magnitude. If the wire were in fact 25 gauge (which are less than 0.5mm in diameter) the voltage drop would be just under 7.1% for a 1m wire and you would need to crank up the supply voltage a bit.

I would be more worried about the quality of the brick myself, and the easiest way to be happy is to measure the voltage on the +12v rail whilst it is under load.

If still paranoid, use the 120-WI-25 and feed it a nominal 14v

Vicotnik · **Posted:** Tue Jan 20, 2009 2:38 pm

I had problems with low +12v (~11.3v under extreme load) so I made an additional connection for +12v and ground. Gave me ~11.7v and my instability problem went away. Using PicoPSUs is still very much DIY..

ryboto · **Posted:** Wed Jan 21, 2009 6:09 am

Vicotnik wrote:

I had problems with low +12v (~11.3v under extreme load) so I made an additional connection for +12v and ground. Gave me ~11.7v and my instability problem went away. Using PicoPSUs is still very much DIY..

So, you soldered directly to the Pico? I just worry about my soldering skills. What I have done is solder directly from the incoming brick(from the 12v supply) to the PCIE-power and ATX-12v 4-pin CPU power plug. This should greatly reduce the amount of current passing through the Pico. It also lets me use the Pico in greater than 120W load situations, since the Pico is only handling a portion of the video card, the MB and a single HDD.

Vicotnik · **Posted:** Wed Jan 21, 2009 6:57 am

I connected +12v and ground directly from the brick into the "molex system".

So now everything gets +12v no matter if the system is on or not. Don't know if that's ok in the long run, but since I run the system almost 24/7 and power off the brick via a switched powerstrip the few times I do shut down I hope it will be ok.

ryboto · **Posted:** Wed Jan 21, 2009 7:03 am

Vicotnik wrote:

That is exactly what I did. +12v and ground directly from the brick into the "molex system".

So now everything gets +12v no matter if the system is on or not. Don't know if that's ok in the long run, but since I run the system almost 24/7 and power off the brick via a switched powerstrip the few times I do shut down I hope it will be ok.

I'm in the same situation, only powere the system off on rare occassions, and when I have, it's been fine. Power draw at the wall is ~ the same as it was before I spliced into the brick's delivery line. The motherboard controls the power-up of the components, so as long as that's off, the rest shouldn't be drawing any power...in theory.

greenfrank · **Posted:** Tue Jan 27, 2009 6:32 pm

I have a question. My system requires very low wattage (around 30w at idle, peak around 40w), so I would try to feed the picopsu 120 with a low power brick (50w max: 12v-4.5a), that is far less expensive than the powerful 80-120w bricks.
My concern is voltage range/stability.
I did check the brick output with a multimeter: is aprox. 12.8v. Is it safe for the picopsu? I mean, which is the maximum safe range of voltage input?
:?:

*here is reported a maximum range up to 13.5v:
http://tarzan.ituner.com/support-center ... d=2&id=107

ryboto · **Posted:** Tue Jan 27, 2009 7:27 pm

greenfrank wrote:

I have a question. My system requires very low wattage (around 30w at idle, peak around 40w), so I would try to feed the picopsu 120 with a low power brick (50w max: 12v-4.5a), that is far less expensive than the powerful 80-120w bricks.
My concern is voltage range/stability.
I did check the brick output with a multimeter: is aprox. 12.8v. Is it safe for the picopsu? I mean, which is the maximum safe range of voltage input?
:?:

*here is reported a maximum range up to 13.5v:
http://tarzan.ituner.com/support-center ... d=2&id=107

I would imagine it's fine. Mine feeds the Pico with 12.4v, but there's voltage losses across the connections, so it's really seeing like 11.98v. So, I wouldn't worry too much about it.

greenfrank · **Posted:** Tue Jan 27, 2009 8:50 pm

thanks ryboto, I hope the connections will drop the voltage a bit, just to fit in the 12v range.
I did again the measurement with multimeter: the brick DC output oscillate between 12.7v and 13.3v, so the average is closer to 13v. Picopsu is going to receive less, safely in the range of 12-13v.
The brick is a cheapo chinese multi-voltage power supply for laptops. Don't get hot, only warm a little.

lutorm · **Posted:** Fri Jan 30, 2009 8:26 pm

I just got a pico and a 5A brick from mini-box.com and unlike the one reviewed, this one definitely does not have active power factor correction. The PF at 30W is 0.55. This brick is marked "EPS". Anyone else see these poor power factors too?

Greg F. · **Posted:** Thu Aug 11, 2011 5:49 am

Can I use one of these?
http://www.newegg.com/Product/Product.a ... 6812200468

Sapphire AMD e350
If I have three HDs hooked up will that be too much? It would be one 2.5 and two 2 TB Samsung 3.5 inch.

Vicotnik · **Posted:** Thu Aug 11, 2011 6:07 am

Greg F. wrote:

Can I use one of these?
http://www.newegg.com/Product/Product.a ... 6812200468

Sapphire AMD e350
If I have three HDs hooked up will that be too much? It would be one 2.5 and two 2 TB Samsung 3.5 inch.

That's one expensive cable.. But it would work. This one might also work, and it's not as expensive.
http://www.newegg.com/Product/Product.a ... 6812816015

blind · **Joined:** Wed Dec 12, 2012 9:31 am **Posts:** 1

hello,

I don't understand "efficiency is calculated as DC watts in ÷ DC watts out × 100%". What is "watts in"? - power that PSU produces or power it uses from wall outlet? I'm just confused.. for me "watts in" sounds as input power which it takes from outlet, while "watts out" is what it produces - then formula should be reversed.

MikeC · **Posted:** Thu Dec 13, 2012 6:23 am

blind wrote:

hello,

I don't understand "efficiency is calculated as DC watts in ÷ DC watts out × 100%". What is "watts in"? - power that PSU produces or power it uses from wall outlet? I'm just confused.. for me "watts in" sounds as input power which it takes from outlet, while "watts out" is what it produces - then formula should be reversed.

You are right. Amazing no one noticed the error till now... after all these years! Our actual data and calculations were done correctly, though, so perhaps that's why this was never noticed before. Corrected.

Tiny, Silent and Efficient: The picoPSU

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