Question One motherboard, two power supplies, and 6 feet of separation

Aug 18, 2019
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This is a bit of an odd question because it is a hack of a solution.

Short version is I want to control two power supplies with one motherboard (so they both turn on at the same time but, importantly, also both shut down at the same time when hibernating). The power supplies are about six feet apart. (The second one is just on a shelf)

I've read many threads about putting multiple supplies in one case, combining power supplies, etc. I've also had no problem manually jumpering my second power supply so it turns on but the problem with that is that every time it shuts down it has to be re-jumpered. Apparently the jumper doesn't have anything to do with the 'auto restore at power restoration' feature you see in most BIOS's. Once it's off, it stays off until I take off the jumper and put it back on.

What I'd really like is a splitter for the 24-pin connector that exports the two on/ground wires to a PCI bracket (for ease of removal), then an extension cable about 6' in length, and a connector to the second power supply. I can't find anything like this.

Additional info/ longer version for background:

This is to support a home grown direct attached storage solution. I wanted to be able to run a lot of hard drives and there was no single case that could do this. There are some large rack mount cases with a lot of capacity but the cheaper ones hold about 15 drives and I didn't like that solution. I don't have $1000+ to spend on the nice solutions. I went with DIY mounting, a dedicated Thermaltake 750W power supply (to handle high spin-up load, and 80 PLUS for efficiency), and connected everything using an LSI SAS card with external ports. This actually works great. My server is lightweight and easy to move for maintenance and upgrades, I can expand to as many drives as I want using cheap shucked drives in a JBOD config (pure software disk handling & backup solution), and I didn't spend a lot of money on huge cases.

The problem I have is everything is on a UPS and I when I hibernate my computer I want it to gracefully shut down the second PSU. When power is restored and my computer comes back on, I want to turn on the secondary PSU. Even in normal maintenance when I just want to turn the computer off I want the second PSU to turn off. Pretty simple requirement, can't find a cable harness that does this or even a person listing a DIY approach that worked.
 
Aug 18, 2019
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Consider something like the following products:

https://www.theverge.com/circuitbreaker/2018/9/13/17847244/tplink-kasa-smart-power-strip-control-sockets

Google "usb controlled power switches" for more ideas.
I don't see any way that would help. The power supplies have to be tied together by motherboard control in order to hibernate/wake on power in coordination. It's not a matter of physical difficulty getting to the second power supply, like a smart power switch might help with, but the fact that once off, it has to be jumpered to turn on. This wouldn't help with that unfortunately.
 

Ralston18

Titan
Moderator
This is what made me believe that the smart power strip would work:

From the link:

"The Kasa Smart Wi-Fi Power Strip has six power sockets, which can be controlled through an app or by voice assistants, as well as three USB ports that always remain powered on. Kasa, which comes from the router company TP-Link, is far from the first to make a smart power strip, but it is perhaps the first major brand to do so. And given that, when it comes to power strips, you really want to buy from a legitimate brand, that makes this announcement a notable one.

On top of that, Kasa’s line of smart home products actually work, and its app is fairly easy to use. Once you have the power strip set up, you’ll be able to assign different icons to each socket, so that you can identify what’s plugged into them — be it a computer, a fan, a lamp, or something else. The app also integrates with Alexa, the Google Assistant, and Cortana, so you can control the sockets by voice. Kasa says that it’s working on HomeKit support as well but doesn’t have a date for when it’ll be ready
."

So the app would be used ( so I thought) to power down the second PSU when the computer was shutdown.

Likewise, when the computer is powered on, then the app (via startup) would turn on the second PSU.

Unfortunately, the strip is not controllable (as near as I can discover via the User Guide) via Windows.

The following product link is much closer to what I had in mind:

https://energenie.com/Repository/7556/EG-PM2_manual---6bc60b0d-e1da-4846-8944-f90176bbe588.pdf

Not sure how the hibernation requirement would be/could be addressed.
 
Aug 18, 2019
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This is what made me believe that the smart power strip would work:

From the link:

"The Kasa Smart Wi-Fi Power Strip has six power sockets, which can be controlled through an app or by voice assistants, as well as three USB ports that always remain powered on. Kasa, which comes from the router company TP-Link, is far from the first to make a smart power strip, but it is perhaps the first major brand to do so. And given that, when it comes to power strips, you really want to buy from a legitimate brand, that makes this announcement a notable one.

On top of that, Kasa’s line of smart home products actually work, and its app is fairly easy to use. Once you have the power strip set up, you’ll be able to assign different icons to each socket, so that you can identify what’s plugged into them — be it a computer, a fan, a lamp, or something else. The app also integrates with Alexa, the Google Assistant, and Cortana, so you can control the sockets by voice. Kasa says that it’s working on HomeKit support as well but doesn’t have a date for when it’ll be ready
."

So the app would be used ( so I thought) to power down the second PSU when the computer was shutdown.

Likewise, when the computer is powered on, then the app (via startup) would turn on the second PSU.

Unfortunately, the strip is not controllable (as near as I can discover via the User Guide) via Windows.

The following product link is much closer to what I had in mind:

https://energenie.com/Repository/7556/EG-PM2_manual---6bc60b0d-e1da-4846-8944-f90176bbe588.pdf

Not sure how the hibernation requirement would be/could be addressed.
It's not a bad theory, and is actually what I originally thought my UPS would do. I had the second power supply plugged into the 'controlled by master' ports. The idea was that when the main PC, attached as 'master' powered off, the UPS would shut down the second device. That actually did work, but unfortunately that port isn't also on the battery backup so in a power outage it would shut down immediately. I want my hard drives to shut down a bit more gracefully. Additionally, just providing power to the PSU doesn't turn it on using the adapter which jumpers the pins - so it was more of an off-only option.

Even if that power strip did have a windows app it wouldn't work for this scenario. It's hard to imagine an app reliably working when the PC is shutting down. It also couldn't work at all on startup, when the second PSU with the hard drives has to turn on either before or simultaneously as the main PC so the SAS controller card can initialize them on BIOS start. Not starting until Windows is running wouldn't work. I ended up going with such an overpowered 750W PSU just for those few seconds at boot where every drive is spinning up simultaneously, since staggered spin-up isn't supported the way I have things hooked up. (I hit 300W at boot but run around 80W regularly - still room to expand with more disks later)

Thanks for the suggestion though, that power strip is neat just not for this application.
 
Aug 18, 2019
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I should maybe give an example of what I'm looking for. I found a link to this in another post here at Tom's.
https://www.newegg.com/p/35Y-000B-00009

Basically that, but ideally something that has a PCI expansion bracket and quick-disconnect - plus about 6' of extension. I think there are solutions like this in BTC mining setups but I haven't seen exactly how to make one from the searches I've found. In the mining scenarios they use this to turn on multiple PSUs to power graphics cards; they probably don't care about controlled shutdowns.

I'm also not sure if that would actually handle shutdown/hibernate scenarios. I think those two wires just send the 'turn on' signal. You can shut a PC down by holding the power button down, which are those same two pins I believe, but now I'm making assumptions on behavior.
 

Ralston18

Titan
Moderator
Overall an interesting project....

The logical requirements are straight forward and I would be very surprised if such a thing has never been done before.

You may need some DIY approach to managing the applicable startup and shutdown requirements.

And I expect that there are a number of ways to do so with various tradeoffs involved.

Do a google search using phrasing such as: "electrical circuits for sequencing equipment startups and shutdowns".

E.g.:

https://www.digikey.com/en/articles/techzone/2018/nov/controlling-startup-and-shutdown-power-sequences

http://www.ti.com/power-management/sequencers/overview.html

Change the phrasing to narrow down or redirect search results. Read a few product manuals - you may find some viable options therein.

And hopefully there will be some other ideas and suggestions posted for you. I have no problems with that.
 

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