Ask HN: Can I use another PSU to power a HDD?

[Spock]

I have 2 PSUs, one is an IDE Molex, the other is SATA connectors. The SATA PSU is tempermental, so I use the molex one as I have all IDE devices.

I need attach a few hard drives from another machine which are SATA and my question is, while the computer is powered from molex, can I also plug my SATA PSU into the hard drive, with a SATA cable to my motherboard, and power it that way? Sorry if it doesn't make much sense, I'm rushing and a bit stressed (kids)

[glimcat]

Yes, but you shouldn't. Also, adapters are a couple bucks on Monoprice.

Also, a "tempermental" PSU may need to be replaced before it does destructive testing of the components connected to it.

[Spock → glimcat]

I'm in the UK, and it's something that needs to be done today, I don't have time to order adapters. Also, like I said, I use the molex PSU, which is fine. The SATA is tempermental, hence why I'm not using it.

[brk]

Yes, you can.

Ideally they'll share the same chassis ground (connect the metal cases together), but it's not strictly necessary (based on personal experience).

[dirkdeman]

I guess it could be done, but is our PSU beefy enough to power a couple of HDD's?

[Spock → dirkdeman]

800W PSUs. Would it actually power the drive without being directly into the mobo first?

[nik_0_0 → Spock]

You wouldn't be able to plug in the 24pin ATX connector to the mobo, which is how the PSU gets the signal to turn on. It is a simple bridge of two ports (google for 24pin atx bridge on), which will leave your PSU on all the time, if it has a switch on the back that will make for easy on/off switching.

However, as said above, adapters are much simpler :)