Power Supply A Guide to 12V PSU

syin16

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Aug 10, 2019
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You more or less answered your own question: the voltage has to be considered when looking at those ratings. As we know: Watt = Voltage x Current

So if it is rated for 5A we get...

  • 5A x 110VAC = 550W (used on the AC side, if you live in the US)

  • 5A x 12VDC = 60W (used on the DC side)

In other words: using some connector like that for AC input would work but not for the DC output. If you need a connector that can handle 12VDC / 50A I would have a look for something like the AMASS XT90.

Also note that many of those aviation connectors selling on eBay, Amazon, etc are crap. I would try to get connectors always from electronics distributors like RS, Mouser, etc.
Based on this, i live in Malaysia where the operating voltage is 240V and 50Hz. Based on the specs of the GX12-3 connector, maximum current of 5A and operating Vrms of 250V, so the max power is 5A x 240VAC = 1200W (malaysia). Technically the connector can handle that can of power right? Because i'm planning to order g-stick fm @guryhwa for power rated of 600W. Wonder if the connector he used will be sufficient? Try asking him about all this questions but seems like he's a busy guy
 

REVOCCASES

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Based on this, i live in Malaysia where the operating voltage is 240V and 50Hz. Based on the specs of the GX12-3 connector, maximum current of 5A and operating Vrms of 250V, so the max power is 5A x 240VAC = 1200W (malaysia). Technically the connector can handle that can of power right? Because i'm planning to order g-stick fm @guryhwa for power rated of 600W. Wonder if the connector he used will be sufficient? Try asking him about all this questions but seems like he's a busy guy

Gury has quite some experience and knowledge about that stuff. Certainly more than we all together. 😅 I am sure he will use connectors suitable for his products when you order a complete set from him.
 

BaK

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In general I would recommend to always stay within ratings given by the manufacturer.

My personal experience is: I had (no-name / generic) connectors failing way below their claimed ratings but I also had connectors which would work just fine at almost double of their official ratings. Sometimes it depends on the quality and if the manufacturer considered safety margins. Luckily I have access to HiPot and Load Testing equipment so I can check connectors before using them.

The two product pages you linked look pretty similar to me. Maybe one of those are better insulated. Or there could just be an error in one of the descriptions. Not sure.

As @Valantar pointed out, the solder terminals look pretty close to each other. For higher voltage applications where safe creepage distance cannot be maintained there should be some separators in between. If there there is not enough space for separators, @Valantar 's idea of using epoxy is also sometimes used.

I have no experience with CnLinko products so it would be a wild guess to say it's safe to use. If in doubt, I would always ask the supplier / manufacturer if it's safe to use for your application. Or just go with a connector from a well known brand where you can be sure that ratings match with your application.

I asked two electrician friends here.
First one agreed with my calculation and said I will be good, but only until I showed him the connector for real and he realized how small it is.
He then changed his mind telling me the pins are indeed small and close to each others for a 250V usage.

Second one was embarrassed to give me an clear answer, he ended up asking me if I always will be around when the computer will be running. Which I think says all...

That's why I sent a message to CnLinko, I will report here what they say if/when they answer.

But I guess I will have to switch to a more common C6 socket :\
 

Curiosity

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All I can say to the credit of XT/MR/MT connectors is that gury uses them in a few/ several of his power supply units and cases seemingly with no issue.
You're right though, I'm pretty sure those connectors I mentioned are generally designed for use with batteries for RC and other hobby electronics.

Maybe I should find a different connector for my power inlet though, i chose the MR30 because of it's small size, at the time thinking I had almost no space to fit a power inlet. Case revisions have left me with more empty or at least potentially empty space than when I made that decision almost a year ago (D:)
 

Choidebu

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Just to chime in,

I had my doubts about MR/MT connectors for AC which was then confirmed by @petricor 's thread (for ~800W application).

Just don't - the plugs and sockets' connection will arc at that wattage, and even if you only intended it to be internal connection, you'd have to trust yourself to do a very good job at soldering and insulating the cables running _from_ them.

GX16 aviation connectors looks cool and generally safer against arcing because the female leads are further in the plug insulation than XT/MR/MT families. The safest is of course IEC combos, because on top of recessed female leads, if you look closely they always make ground pins connect first before hot/live leads preventing arcing.

The only gripes I have with GX16 is the fact that you have to solder your own wall to female plug cables, as nothing is available off the shelf. On that point it's the same thing with XT/MR/MT - you have to trust yourself to solder the cables well enough.

With IECs, you'd only need to worry abt soldering the socket. You can go crazy with the heatshrink insulation - hot glue, epoxy or electrical tape - doesn't matter since it's inside the case and doesn't need to look pretty or compact enough to fit a plug's housing.
 

Phuncz

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Interesting. I always thought arcing was voltage dependent, not amp dependent.
 

Choidebu

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Without wanting to sound like I actually understand the physics behind it (I consider myself like @Valantar , a mere back alley illusionist)....

Spontaneous arcing in exposed conductor is indeed voltage dependent.

But this phenomenon of current burning through insulations on the short instance of an electrical connection being made (or even multiple connect and disconnect, like when we wiggle our way in then microscopically connections are made then undone then made and so on until it's finally _really_ made), I just conveniently call arcing as well for lack of my knowledge of better word.

Now this 'arcing', in my observation, is dependent on target input impedance, contact area, max current the supply can provide, and thickness of insulation material between live/lead and its return path.
 
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Curiosity

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Has anyone seen this pcie form factor power supply before?
12v 5.4 a for a total of 65w, could be a cool use with an Apu only build in a small case.

 

infoberg

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Has anyone seen this pcie form factor power supply before?
12v 5.4 a for a total of 65w, could be a cool use with an Apu only build in a small case.

Interesting concept! But 65W sounds like it's suitable only for very small builds, which mostly don't have place for any PCIe card, right?
 

Valantar

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Has anyone seen this pcie form factor power supply before?
12v 5.4 a for a total of 65w, could be a cool use with an Apu only build in a small case.

That's really neat! Seems like it would be a perfect fit for something like a Lazer3D HT5 build with a low-power APU.
 

Curiosity

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@infoberg
It's true, most build that would be happy with just 65w don't have room for a pcie device. But I imagine there are a few use-cases. The only off the shelf use I can think of would be a minibox m300, it's 3.7l and has a single pcie slot over the Mobo but usually relies on a picopsu running off a brick. It could also have a place is custom jobs.

@Valantar the only issue I see there is that unless I'm wrong, it's a full height device.
But maybe it could be made to fit somehow.
I imagine if one felt like it it could also be used to power an APU with a rouuugh diy egpu. This power the Mobo/Apu package, then you have a pcie slot open to accept a GPU on a riser that combined have their own 12v supply. Have both powered off tand connect the GPU, then apply power to the gpu, then mobo, then actually hit the power switch.
I've kind of tried that rough idea before and it functioned.
It was jank af tho
 

Valantar

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@infoberg
It's true, most build that would be happy with just 65w don't have room for a pcie device. But I imagine there are a few use-cases. The only off the shelf use I can think of would be a minibox m300, it's 3.7l and has a single pcie slot over the Mobo but usually relies on a picopsu running off a brick. It could also have a place is custom jobs.

@Valantar the only issue I see there is that unless I'm wrong, it's a full height device.
But maybe it could be made to fit somehow.
I imagine if one felt like it it could also be used to power an APU with a rouuugh diy egpu. This power the Mobo/Apu package, then you have a pcie slot open to accept a GPU on a riser that combined have their own 12v supply. Have both powered off tand connect the GPU, then apply power to the gpu, then mobo, then actually hit the power switch.
I've kind of tried that rough idea before and it functioned.
It was jank af tho
That's a pretty decent idea. Could probably be made to work with some sort of electronic power switch for the external PSU, i.e. one that turns it on once there's power internally. It would need to react quickly, of course.

Btw, the product page says "low profile extension card format", so it should be half-height.
 
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Curiosity

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That's a pretty decent idea. Could probably be made to work with some sort of electronic power switch for the external PSU, i.e. one that turns it on once there's power internally. It would need to react quickly, of course.

Btw, the product page says "low profile extension card format", so it should be half-height.
I hadn't noticed that, looking closer iat it it does seem to be half height. Very interesting.
Genuinely tempted to try to get my hands on one. I've been considering getting the kontron d3664-b but haven't mentally committed yet, but if I did it wouldn't hurt to get both at once.
 
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robbee

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Excited to join the 12V club! Just received my Meanwell LSP-160 so I can combine it with my Minibox 160-XT which has been using an external brick until now. That thing is small, so cute :D

Will be using it for an i3 + 75W gpu build. I'll post more info as the build progresses as I haven't seen this particular Meanwell model being used often besides @BaK his 'box' :)

EDIT: it's alive!

 
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Valantar

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Excited to join the 12V club! Just received my Meanwell LSP-160 so I can combine it with my Minibox 160-XT which has been using an external brick until now. That thing is small, so cute :D

Will be using it for an i3 + 75W gpu build. I'll post more info as the build progresses as I haven't seen this particular Meanwell model being used often besides @BaK his 'box' :)

EDIT: it's alive!

Glad to hear it works, but you should be aware that that PSU is pretty far outside of several points of the ATX specification - rated for 240mVp-p ripple and just 10ms hold-up time.

Luckily their test report paints a much better picture of just 60mVp-p of ripple (though that spec does leave a lot of room for variance between production runs) and 15ms of hold-up time, which comes close to the ATX spec of 17ms (IIRC). But depending on the quality of your specific unit you might see some instability in certain scenarios, especially if you have poor/noisy AC power.

Really like the compactness of the PSU though, and that looks like an excellent little build!
 

robbee

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Luckily their test report paints a much better picture of just 60mVp-p of ripple (though that spec does leave a lot of room for variance between production runs) and 15ms of hold-up time, which comes close to the ATX spec of 17ms (IIRC). But depending on the quality of your specific unit you might see some instability in certain scenarios, especially if you have poor/noisy AC power.

Thanks for the heads up. I did read @BaK his build log carefully before deciding on this PSU because things looked good on his part. If things go bad, I still have the option to go for the 24V version and use the HDPlex DC-ATX (which I already own) to smooth out some of the ripple but the HDPlex somewhat limits my choice of CPU coolers and is not compatible with the NH-L12 that I currently use.
 
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BaK

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Excited to join the 12V club! Just received my Meanwell LSP-160 so I can combine it with my Minibox 160-XT which has been using an external brick until now. That thing is small, so cute :D

Will be using it for an i3 + 75W gpu build. I'll post more info as the build progresses as I haven't seen this particular Meanwell model being used often besides @BaK his 'box' :)

EDIT: it's alive!
Welcome to the club! :)
Nothing to complain so far with my B01T3 build, quite happy with it.
Fell free to ask if you have questions, will be glad to answer if I can!

About your build, what kind of i3 CPU is it? Unless it is a T version, along with a 75W GPU means you are going to be close to the PSU max power.
I would then suggest to add a fan close to the PSU or have a case with good airflow, mine was getting quite hot before the 120mm fan of the CPU cooler nearby helps moving some air. Same for the PDCB btw, when only drawing around 100W from the wall.

Oh and how are you going to deal with the GPU always ON problem?
 

Valantar

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Welcome to the club! :)
Nothing to complain so far with my B01T3 build, quite happy with it.
Fell free to ask if you have questions, will be glad to answer if I can!

About your build, what kind of i3 CPU is it? Unless it is a T version, along with a 75W GPU means you are going to be close to the PSU max power.
I would then suggest to add a fan close to the PSU or have a case with good airflow, mine was getting quite hot before the 120mm fan of the CPU cooler nearby helps moving some air. Same for the PDCB btw, when only drawing around 100W from the wall.

Oh and how are you going to deal with the GPU always ON problem?
If the GPU is slot-powered, won't the 12V supply be switched through the PDCB?
 
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BaK

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If the GPU is slot-powered, won't the 12V supply be switched through the PDCB?
Right, I'm too much into my latest build which uses an M2426 to deal with the GPU ON/OFF, sorry...
 

robbee

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Welcome to the club! :)
Nothing to complain so far with my B01T3 build, quite happy with it.
Fell free to ask if you have questions, will be glad to answer if I can!

About your build, what kind of i3 CPU is it? Unless it is a T version, along with a 75W GPU means you are going to be close to the PSU max power.
I would then suggest to add a fan close to the PSU or have a case with good airflow, mine was getting quite hot before the 120mm fan of the CPU cooler nearby helps moving some air. Same for the PDCB btw, when only drawing around 100W from the wall.

Oh and how are you going to deal with the GPU always ON problem?
First step will be to recycle my old setup (i3 6100 + 1050ti) but I may look at the i3-10105F later on. With a power usage of about 50W on full load, that seems pretty manageable. I may go down the same route as you with a 120mm fan hovering above the PSU and 160-XT though. I don't expect any issues with the 160-XT at all though, it has been running for some years without cooling in my previously mentioned setup.
 
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