Power an HDD with an external PSU, anything to know?

Hi,
so a couple of days ago i was fortunate and got my hands on a server ( HP proliant dl180 g6) and ran into a small problem.
The server came with 2x2TB sas drives and I was not thinking about the mbr limitations. Now the idea I had to make it work was to get 2-4 small capacity sas drives to stuff my front bays with ( connected to a raid card and I want raid 10 or at least raid 0) and the bigger capacity drives I plan to hook up to the sata ports on the board, so far so good. But the server does not come with sata power connectors. Now my plan is to short an atx PSU and use its sata power to run my drives. My question here is, are there any known issues with this plan?

Side infos:
the ATX PSU will be turned on using relays and an arduino, so that the atx supply will turn on a few seconds prior to the server so the drives will be detected...

Any help and/ or suggestions are welcome :slight_smile:

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If the existing PSU has spare molex connectors, you could get adaptor cables relatively cheaply?

Ive done this when I needed information off of a spare drive. I have not had any problems.

Well sadly there are no molex connectors in there, but this might help me get more HDDs in my Gaming case :slight_smile:

It's janky but yes it should work fine. Just be mindful of the jumper you use, suddenly pulling power from the drives could be very problematic

That's good to know, I didn't think that it would, because electrically all the supply power is the same and data is of course being dealt with by the sata from the board.

Well i thought for the start sequence i spin up the drives just a little prior to the server starting and for shutting down i would wait until the server is completely shut off. Other than the drives shutting off while there is data flow, there shouldn't be anything to worry about right?

I would reccomend something like this to make sure your harddrives and whatnot power up at the same time

The suggested Dual PSU cable would not work, as the HP Server does not have a Standard ATX Layout, if i remember it correctly. You could look into it and hack it up, but otherwise the eheim Watercooling pump from aquacomputer came often with a Standard ATX Plug, that connected the green wire with ground. Just use one of those. If you want to advance that solution, just externd that wire to a Switch, that you put in front of the case.

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I just checked and you are correct. Though I did not expect there to be one :smiley:

Also i forgot to say, I am confident in soldering :smiley:

To get a second psu to work without connecting to a motherboard,
the only 2 wires that need to be connected together are the green one from the 24pin motherboard powerplug and a black ground wire if i´m right.
Atleast with an atx psu that is.
So yeah if you are a bit creative there are plenty of options that could work.

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Make sure all the PSU's and chassis share the same earth amd mostly will be fine. If the live rails are deferent levels ie one PSU 12V rail is 11.5 and the others is 12.2. there could be problems but that is a minor problem mostly....Keep everything earthed together.

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So here is my current plan (pun intended) , I will short the PSU so it will turn on as soon as the 230VAC are hooked up, the PSU will only power the drives i need to power, nothing else. An Arduino will close a relay which will give 230VAC to the PSU. There will be a delay before the redundant server PSUs get power through another relay and will then turn on( i set this up in BIOS). So i will have a single button to push to start the server. For shutting down I will for now have to shut down the external PSU manually. The PSUs all share the same electrical earth through the plug.

So here is my (probably) final update.
I have run this setup without any issues on a dual Xeon server with a total of 7 HDDs. A word of warning for those who want to use a microcontroller to switch on the setup, opening a circuit that draws even relatively low current can cause arcing which is not something you want. Also, you may consider altering the case first to properly route the SATA power( or whatever you want to get in there…). Also, find a way to fix the external PSU to the case. I personally decided just to create custom plugs with sockets on the outside of the case to plug it in/out as wanted. No drive failures after a (so far) total of 341 restart cycles. I also hooked up my micro controller to compare the voltage of the internal 5V with the external 5V and if external > internal to shut off the external power so I would not have to. The controller is also integrated with my little network of devices I want to be able to switch on/off from my computer. I don’t know if I should go as far as to recommend this method, but in a pinch, it seems to work.
Have a good one and thanks for all the help/suggestions/hints!

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an old at power supply does not need to be connected to the motherboard as it’s switch is separate from the panel controls( a sata power adapter can be used for sata drives )
I keep a couple at supplies around for testing drives

or you could use an external drive case or docking station