Power Supply A Guide to 12V PSU

[Valantar]

Hi,

I received today the MeanWell EPP-120S-12 and all the components. All nice and well, besides that I ordered 16AWG wires instead of 18AWG.

Spoiler: Picture of components and EPP-120S-12

So I temporarily hooked everything up - as it is a temporary assembly I didn't really heatshrink much and didn't prepare the earth cable. I didn't achieve the best crimpings but haven't done it in decades and also the thicker wires didn't help. I should receive the thinner ones tomorrow and I hope the crimps will look much smarter.

Spoiler: Picture of a not exceptional crimping

https://i.paste.pics/824b081715ea94276de5435e00446240.png

All decent enough and well, however..

Spoiler: Picture of the final setup

...if I stand close enough to the MeanWell, it emits an intermittent high frequency noise / whirring.
Has anyone had that with this or other MW units?

I would like to mention a big thanks to @Thehack for writing the guide and @toddwas for the lovely diagram.
And still thanks to @Valantar and @smitty2k1 for the recommendation of this little unit, I am really loving it! (that is, besides this faint noise ? )

That looks great! I'm guessing the noise is some sort of coil whine; it's pretty much unavoidable in any voltage regulation circuit. If it bothers you the best solution seems to be to identify the offending coil and glue it down tightly, either with superglue or some sort of epoxy, being sure to get it under the edges of the part to adhere it to the PCB as much as possible. I've never heard any from my UHP-350-12, but that whole unit is encased in thermal epoxy from the factory, and I haven't put my RPS-200-12C to use yet.

 

[NateDawg72]

...if I stand close enough to the MeanWell, it emits an intermittent high frequency noise / whirring.
Has anyone had that with this or other MW units?

My EPP-400 has coil whine like that. I used it to notice it at the last place I was living and it would bug me, I'd put things between myself and the computer to make the noise less noticeable. The ambient noise where I'm living now must be higher because I'm not really hearing it now. I know the place I lived before was very quiet.

Putting mass between yourself and the PSU is the simplest way to deal with it. Have it inside a case, under the desk, behind the monitor, keep it farther away, etc. Only other option is to do as Valantar suggested and glue it. I've been told hot glue can do the job too but I never got around to trying it on my EPP-400.

 

[Lone]

...if I stand close enough to the MeanWell, it emits an intermittent high frequency noise / whirring.
Has anyone had that with this or other MW units?

I used to have an EPP-200-12, and it also made noise. That was one of the reasons I got rid of it.

 

[k0n]

My EPP-400 was surprisingly silent in any situation.

 

[SpaceTofu]

Quite some mixed feedback about the noise, I suppose there could be variances between different MW products and also variances between different units of the same product; and also variances amongst users of course!

@smitty2k1 it is so tiny indeed, it is almost a pleasure to watch! Thanks to this massive upgrade, I can only but dream about building (in the future) my own very compact case, almost transportable.

I suppose yes it is coil whine, it sounds like something is slightly frying.
I have to say, right now the EPP-120S-12 is completely uncovered sitting (into/onto an old plastic Iphone 5s case and it is covering barely more than half of it, such it is tiny!) in a completely uncovered case so I would hope that the whine/noise will get obliterated once everything is boarded up.

@NateDawg72 thank you for your advice of laying mass between PSU and my ears, will keep it in mind for when I will eventually design my case!

On a different note, can anyone comment what you think should be the hottest component that I should be safe touching with a thermometer with a metal tip? ? Picture again below:

 

[Valantar]

Quite some mixed feedback about the noise, I suppose there could be variances between different MW products and also variances between different units of the same product; and also variances amongst users of course!

@smitty2k1 it is so tiny indeed, it is almost a pleasure to watch! Thanks to this massive upgrade, I can only but dream about building (in the future) my own very compact case, almost transportable.

I suppose yes it is coil whine, it sounds like something is slightly frying.
I have to say, right now the EPP-120S-12 is completely uncovered sitting (into/onto an old plastic Iphone 5s case and it is covering barely more than half of it, such it is tiny!) in a completely uncovered case so I would hope that the whine/noise will get obliterated once everything is boarded up.

@NateDawg72 thank you for your advice of laying mass between PSU and my ears, will keep it in mind for when I will eventually design my case!

On a different note, can anyone comment what you think should be the hottest component that I should be safe touching with a thermometer with a metal tip? ? Picture again below:

If you're looking to measure temps the metal heatsink as close to where the mosfets are mounted to it ought to be the best spot. Grounded, should be safe to touch (though still don't touch it with your hands unless you really like stupid risks), and directly connected to the hottest components.

 

[watts_happening]

Heads up that the EPP-100-12 is on sale at Newark for $12.78, normally about four times that price. I ordered 4 of them for future projects, although I only "need" 1 or 2. ?
https://www.newark.com/mean-well/epp-100-12/power-supply-ac-dc-12v-6-3a/dp/44AC4712

 

[Curiosity]

Very nice, I still regret not buying the WLP350 I'm looking at using when I saw it for $50 at Arrow vs can it's usual $80-100.

 

[smitty2k1]

Heads up that the EPP-100-12 is on sale at Newark for $12.78, normally about four times that price. I ordered 4 of them for future projects, although I only "need" 1 or 2. ?
https://www.newark.com/mean-well/epp-100-12/power-supply-ac-dc-12v-6-3a/dp/44AC4712

Let me know if the 400w or 500w ever goes on sale

 

[Questl]

Hey! Planning to use a MeanWell EPP-300-12 in my build after reading this thread!

I am worried because it's an open frame PSU, which I've been told time and again is A Bad Thing. My main concerns regard caging or leaving the PSU bare: specifically worried about RF, short circuits, and heat dissipation. Which of these were considerations in y'all's builds, and how did you manage them? Lastly, I have yet to find a thorough guide on jumping the device to drain it, a concern which "let it sit for a few days" does little to assuage.

 

[smitty2k1]

Hey! Planning to use a MeanWell EPP-300-12 in my build after reading this thread!

I am worried because it's an open frame PSU, which I've been told time and again is A Bad Thing. My main concerns regard caging or leaving the PSU bare: specifically worried about RF, short circuits, and heat dissipation. Which of these were considerations in y'all's builds, and how did you manage them? Lastly, I have yet to find a thorough guide on jumping the device to drain it, a concern which "let it sit for a few days" does little to assuage.

If you're worried why not grab the RPS-300-12-c? It has a basic frame to protect the components.

 

[Valantar]

Hey! Planning to use a MeanWell EPP-300-12 in my build after reading this thread!

I am worried because it's an open frame PSU, which I've been told time and again is A Bad Thing. My main concerns regard caging or leaving the PSU bare: specifically worried about RF, short circuits, and heat dissipation. Which of these were considerations in y'all's builds, and how did you manage them? Lastly, I have yet to find a thorough guide on jumping the device to drain it, a concern which "let it sit for a few days" does little to assuage.

What @smitty2k1 said above. As to heat, remember that the 300W rating is with a specific, non-trivial amount of airflow onto specific parts of the PSU, EPP PSUs are rated for less than their full output when passively cooled.

 

[Thehack]

What @smitty2k1 said above. As to heat, remember that the 300W rating is with a specific, non-trivial amount of airflow onto specific parts of the PSU, EPP PSUs are rated for less than their full output when passively cooled.

It's somewhere in between. There's not a hard cutoff, and convection rating is a zero airflow situation, which is not what computers are. Even if there is no direct airflow, there is some movement of air which moves the heat out.

I would say, if you have minor air movement, and as long as it is not a hot pocket, you can probably expect 75-80% of the max output to be realistic.

 

[PLLovervoltage]

For the 6 pin, the main post suggests soldering and heatshrinking wires to combine them. Is combining them at the plug by crimping the wires together not recommended?

 

[blubblob]

For the 6 pin, the main post suggests soldering and heatshrinking wires to combine them. Is combining them at the plug by crimping the wires together not recommended?

It depends on what you mean by "combining them at the plug by crimping the wires together". You can of course use something like a butt connector to crimp the wires together instead of soldering them. This is also suggested as an alternative in the op.

If you mean to use the crimp connector at the plug to "U-turn" two wires back to the third for a single crimp connection containing the three terminals wires and the main wire: that would be a bad idea. The crimp connector on the MiniFIt Jr. Receptacle are only rated for AWG 18-24. You can't stuff more wires in there and still achieve a proper crimp. The bad connection would likely melt that pin of the connector over time.

 

[Thehack]

It depends on what you mean by "combining them at the plug by crimping the wires together". You can of course use something like a butt connector to crimp the wires together instead of soldering them. This is also suggested as an alternative in the op.

If you mean to use the crimp connector at the plug to "U-turn" two wires back to the third for a single crimp connection containing the three terminals wires and the main wire: that would be a bad idea. The crimp connector on the MiniFIt Jr. Receptacle are only rated for AWG 18-24. You can't stuff more wires in there and still achieve a proper crimp. The bad connection would likely melt that pin of the connector over time.

You can buy 16 AWG terminals. Should get a decent crimp.

 

[blubblob]

You can buy 16 AWG terminals. Should get a decent crimp.

not if you try to stuff 2x18AWG+1x16AWG into it.

 

[Thehack]

not if you try to stuff 2x18AWG+1x16AWG into it.

If it is a fairly low current GPU, i don't see the problem with using 2 double crimps. You would just daisy chain it. A single 18 awg crimp can handle 6.3A you need, and it is within the capability of the pin. Normally 6 pin GPUs don't draw more than 75W, if they respect the 6 pin specs.

Alternatively, you can use a WAGO 221 pack, like this assortment kit: amazon.

 

[chx]

I hope this is on topic: my battle plan is to use a Dell DA-2 and this https://www.newegg.com/p/N82E16812198032 PCIe to 4+4 pin feeding one 4 pin into a PicoPSU the other into the motherboard. The only possible problem I can see with this solution is the motherboard would receive 12V before the ATX part comes on. Can that be a problem?

According to https://egpu.io/forums/psu-cables/us3-dell-da-2-pcie-splitter/ it's possible to force a PCIe 6 pin like this on the DA-2 and then use a highly sophisticated McGyver device to force the DA-2 to be on And yes, I have a multimeter and I will test the voltages before feeding them anywhere.

 

[Thehack]

I hope this is on topic: my battle plan is to use a Dell DA-2 and this https://www.newegg.com/p/N82E16812198032 PCIe to 4+4 pin feeding one 4 pin into a PicoPSU the other into the motherboard. The only possible problem I can see with this solution is the motherboard would receive 12V before the ATX part comes on. Can that be a problem?

According to https://egpu.io/forums/psu-cables/us3-dell-da-2-pcie-splitter/ it's possible to force a PCIe 6 pin like this on the DA-2 and then use a highly sophisticated McGyver device to force the DA-2 to be on And yes, I have a multimeter and I will test the voltages before feeding them anywhere.

You can only do a direct ac-dc to motherboard if your motherboard supports 12V in.

100% of it needs to go into the Picopsu.