Power Supply A Guide to 12V PSU

Choidebu

"Banned"
Aug 16, 2017
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Sorry are we even talking about the same epp-200-12 here? I cannot see anything on the datasheet about 5VSB nor PS_ON nor PWR_OK.
 

arataisozaki

Chassis Packer
Oct 20, 2018
15
3
@Thehack Yes, that's exactly what I was thinking. Cool, I'll see if I get the chance to try it out.
I feel like a ssr tends to require quite a bit of space. I was thinking about using one of those cheap mosfet boards of ebay. they go for like 1 $ and are rated for 400 W with heatsinking even more.

@Choidebu Sorry, I was switching forth and back. You are absolutely right. The EPP-200-12 does not have this control circuitry and a much more complicated build would be needed.
 

Thehack

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@Thehack Yes, that's exactly what I was thinking. Cool, I'll see if I get the chance to try it out.
I feel like a ssr tends to require quite a bit of space. I was thinking about using one of those cheap mosfet boards of ebay. they go for like 1 $ and are rated for 400 W with heatsinking even more.

@Choidebu Sorry, I was switching forth and back. You are absolutely right. The EPP-200-12 does not have this control circuitry and a much more complicated build would be needed.

The EPP-200-12 you just need to get a beefier PDCB. These units use very low standby power so there's no reason they can't just on 24/7.

Yes. The SSR will take quite a bit more space I agree. The smaller you go, the more hacky you get though. It's a balancing act of getting really deep into modifying stuff and making it user friendly for beginners.

This was a good conversation, and it does give me a couple ideas of implementing a fully MW compatible PDCB. Please provide a report if it works as expected.
 

Tossy

Average Stuffer
May 3, 2018
84
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I'm looking for a place to buy a decent PDCB, e.g. the picoPSU-160-XT as recommended in this thread. It will only be powering a 2400g (overclocked). But I can't find a shop which sends from within Europe, leading to high delivery costs. Does anyone know a shop? Would be perfect if it would be seated in the Netherlands :D.
 

Thehack

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I'm looking for a place to buy a decent PDCB, e.g. the picoPSU-160-XT as recommended in this thread. It will only be powering a 2400g (overclocked). But I can't find a shop which sends from within Europe, leading to high delivery costs. Does anyone know a shop? Would be perfect if it would be seated in the Netherlands :D.

Have you tried Amazon? It should not be expensive for Amazon DE to ship to Netherlands.
 

smitty2k1

King of Cable Management
Dec 3, 2016
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I'm looking for a place to buy a decent PDCB, e.g. the picoPSU-160-XT as recommended in this thread. It will only be powering a 2400g (overclocked). But I can't find a shop which sends from within Europe, leading to high delivery costs. Does anyone know a shop? Would be perfect if it would be seated in the Netherlands :D.
I got mine for cheap off an eBay seller. I know a lot of eBay sellers ship international (or from China).
 

Tossy

Average Stuffer
May 3, 2018
84
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Thanks you both. Google only showed amazon.com, didn't think about looking on amazon.de myself.
I don't like ordering via eBay. Have heard too many stories of fake products send.
 

Tossy

Average Stuffer
May 3, 2018
84
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And here again with a few questions. My picoPSU came in today and I ordered a Meanwell RPS-200-12-C. I looked at the wiring of the picoPSU and the examples of the first post of this thread and a few questions arose. As mentioned above I will only power a (overclocked) 2400G.

1.
A) Is it better to connect four of the six outlet pins of the meanwell to the mainboard EPS (4/8pin) connector and use the remaining two to power the picoPSU (which only has two input wires anyway).
OR
B) Would it be better to connect four pins of the meanwell to the picoPSU and power the mainboard EPS connector via the picoPSU (seems redundant)?
OR
C) Is it feasible to connect the meanwell and the picoPSU using two wires (of appropriate AWG, e.g. 16) and power the EPS connector via the picoPSU?

2. The cable to connect the picoPSU to the 4/8pin EPS connector has the two 12V+ and the two ground wires bridged, respectively (see image). I have never seen this on normal PSU's. What is the use of it? If I used method A, this wouldn't be necessary, right?



3. More a question out of curiosity, as I won't use the barrel connector. The barrel connector that comes with the picoPSU has only two wires soldered to it. Why are they still using all four pins of the mini-fit junior connector and even bridge these?

Thanks in advance!
 

Thehack

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And here again with a few questions. My picoPSU came in today and I ordered a Meanwell RPS-200-12-C. I looked at the wiring of the picoPSU and the examples of the first post of this thread and a few questions arose. As mentioned above I will only power a (overclocked) 2400G.

1.
A) Is it better to connect four of the six outlet pins of the meanwell to the mainboard EPS (4/8pin) connector and use the remaining two to power the picoPSU (which only has two input wires anyway).
OR
B) Would it be better to connect four pins of the meanwell to the picoPSU and power the mainboard EPS connector via the picoPSU (seems redundant)?
OR
C) Is it feasible to connect the meanwell and the picoPSU using two wires (of appropriate AWG, e.g. 16) and power the EPS connector via the picoPSU?

2. The cable to connect the picoPSU to the 4/8pin EPS connector has the two 12V+ and the two ground wires bridged, respectively (see image). I have never seen this on normal PSU's. What is the use of it? If I used method A, this wouldn't be necessary, right?



3. More a question out of curiosity, as I won't use the barrel connector. The barrel connector that comes with the picoPSU has only two wires soldered to it. Why are they still using all four pins of the mini-fit junior connector and even bridge these?

Thanks in advance!

1. Set up A is the best electrically. But some motherboards react strangely to having 12V rail always on even when the PC is off. B is most reliable way of ensuring it works properly. C I would not do because the pins can only handle so much power, so your limited by the pins.

2. Probably they wanted to used more pins for safety reasons.
 
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Tossy

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May 3, 2018
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Thanks for the explanation. I'll try my luck with set-up A. I can still switch to set-up B if strange things happen.
 

Supercluster

Average Stuffer
Feb 24, 2016
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Hi
Can Meanwell LRS-150-12 be used as pc power supply?
Amazon product
Can't find any other models in India

Almost any power supply with a 12 VDC output can be used with a distribution board in a PC.

Having said that, I should probably also mention some of the reasons why using PSU's designed and optimized for PC's is better for component stability and longevity:
  • Guaranteed maximum ripple and noise rating, which per ATX specification should not exceed 120mVp-p (peak-to-peak). This value measured in the best currently produced power supplies can be lower than 10 mV, which makes it an order of magnitude better at suppressing voltage spikes (oscillations if you prefer) than the specification requires:

  • Hold-up time at full load, which, again, per ATX (intel) specification should be no lower than 17ms: From Tom's Hardware: "Hold-up time is the amount of time that the system can continue to run without shutting down or rebooting during a power interruption". Good PSU's can almost double the value during a full load:

These categories are just to get you started as each has many subcategories that a good PSU reviewer must test in order to know how a unit performs.

If you look at the specification for the MeanWell LRS 150 series, you can see that the guaranteed ripple & noise value (for the 12v model) is higher than what it should be: 150mVp-p vs 120 mVp-p. This suggests that the PSU should not be used for desktop PC's.
However, if you look at the actual test report from a production unit, you can see that the measured value with the particular power supply was well within specification at 28mVp-p.

Holdup time is amazing at 60Hz (i.e. in the US) at 35+ms and under the specification requirement at 50Hz (i.e. in India) at 12+ms depending on the AC voltage.

I hope that you are now a step closer to making an educated decision on whether you should use the PSU in your particular workload and reliability requirement.
 
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CC Ricers

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Thehack

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@Supercluster made very good points at choosing a 12V PSU.

An additional opinion is that the hold-up time doesn't really affect us the same way regular PSU does.

The hold up time is considered after the loss of the power good signal. That is, the PSU should detect the loss of power, cut the power good signal, and then from there the pc complete the operation and prepare for emergency power loss.

The other thing is the hold up time was a requirement developed during a time of slow pcs and even slower disks.

I can't say how much it affects us 12V builders but it does affect us differently. The pc doesn't really see power good signal with a plug in unit.
 
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aquelito

King of Cable Management
Piccolo PC
Feb 16, 2016
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Currently testing this little guy, with a One2 board in "always ON" mode.
Indeed, the 24-Pin direct plug unit controls the PS_ON fuction of the Meanwell EPP-400-12 : no need for load switches anymore :)

It really is the cleanest way to use the Meanwell.

Apart from some cold boot issues, this trio works like a charm.

Designed and built by the guy behind my risers.

 

aquelito

King of Cable Management
Piccolo PC
Feb 16, 2016
948
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@NateDawg72 : still my awfull test bench !



The direct plug unit is directly wired to the EPP-400-12.
The One2 board is also powered by the EPP-400-12, in "always ON" mode.

Maybe I should try to power the direct plug unit through the "always ON" 4-Pin connector of the One2 to avoid cold boot issues ?

Indeed, on some occasions, the LED power of the motherboard will light up then shut down immediately.
The 180mm fan will continue to run but the pump won't start.
No POST.

I have to manually shut down the AC Line then wait and press again the power button to be able to boot.

What kind of inline connectors could I use to extend both 12AWG silicon wires of the direct plug unit ?

@arataisozaki @Thehack : this is the kind of solutions you were mentioning end of October right ?
 
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NateDawg72

Master of Cramming
Aug 11, 2016
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@aquelito I had the same cold boot issues with my PicoPsu 160XT powered directly from EPP-400, fans and stuff would start but wouldn't post. With my Archdaemon I no longer have boot, cold boot, sleep issues of any kind. It is still powered directly from EPP-400. For why it works I have no idea, some part of Gury's design handles it better I guess.

My EPP-400-12 is always on, it isn't synced with my archdaemon.

Edit: does your EPP-400 have coil whine at no loads / extremely low loads? Mine does, in sleep mode, or when the PC is off, or with no load.
 

smitty2k1

King of Cable Management
Dec 3, 2016
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@aquelito I had the same cold boot issues with my PicoPsu 160XT powered directly from EPP-400, fans and stuff would start but wouldn't post. With my Archdaemon I no longer have boot, cold boot, sleep issues of any kind. It is still powered directly from EPP-400. For why it works I have no idea, some part of Gury's design handles it better I guess.

My EPP-400-12 is always on, it isn't synced with my archdaemon.

Edit: does your EPP-400 have coil whine at no loads / extremely low loads? Mine does, in sleep mode, or when the PC is off, or with no load.
Interesting I have no issues with my PicoPSU 160XT and EPP-200-12. It does take about 15-20 seconds after plugging in power before the CPU will boot, not sure if it has to charge some capacitors or something like that.