Second PSU?

[Stonelesscutter]

Is there ever any point in adding a second PSU?

 

I'm (still) planning to build my own case and in it I'll want to make room for lots of hard drives. I won't have many to start with, but that will probably change later on. The design of the case will easily have room for a second PSU. I'm just wondering now if there would be a useful use-case for having two. How many drives could you power on a single PSU along with the CPU and graphics card and all of those parts? Is there something to say for having all hard drives on a separate PSU from all other components, or would that have a downside?

[Chiyawa]

Well, we do have a powerful PSU up to 1600W. Buying 2 PSUs are, well, not really make sense. Anyway, if you want, I think that's okay. I don't see anything wrong by connecting HDD or SSD to a separate PSU. However, do note that you need to trigger both PSU when you switch on your system.

[Stonelesscutter]

17 minutes ago, Chiyawa said:

Well, we do have a powerful PSU up to 1600W. Buying 2 PSUs are, well, not really make sense. Anyway, if you want, I think that's okay. I don't see anything wrong by connecting HDD or SSD to a separate PSU. However, do note that you need to trigger both PSU when you switch on your system.

Thanks! This triggering of a PSU, is this done through the motherboard, or is it just a matter of routing a single power button to both PSUs?

 

Edit: I just realized that shutting down a computer is done by software, so I guess this answers my own question and it's the motherboard which tells the PSUs to power on or power off. So then my question becomes, do you need a special motherboard in order to have it switch two PSUs on or off at the same time? Would there be special software requirements involved?

 

How much power does a single hard drive actually need to run?

[Chiyawa]

55 minutes ago, Stonelesscutter said:

So then my question becomes, do you need a special motherboard in order to have it switch two PSUs on or off at the same time? Would there be special software requirements involved?

Last time I remember ThermalTake has just the thing you need to switch on 2 PSU from the motherboard at the same time (can you believe they design a 5.25 inch bay with a cigarette lighter and an ashtray?). Not sure if this thing still exist any more. Link is here:

https://www.thermaltake.com/dual-psu-24pin-adapter-cable.html

 

However, if you are up to it, you can DIY the connection yourself. All you need is to short the Power On pin to the ground and the PSU will switch on.

 

1 hour ago, Stonelesscutter said:

How much power does a single hard drive actually need to run?

Actually, modern drive are very very efficient and consume less power. Typically, an old 3.5 inch HDD (using IDE) consume less than 40W of power at full operation. This days, some 3.5 inch HDD only consume 25W max, while many consume 10W or lower. The 'old' HDD I got 6 years ago (Seagate Barracuda 7200rpm 160GB SATA 2) is rated at 6.6W (5V 0.72A + 12V 0.52A), or more accurately, 6.24W on 12V power rail. SSD is almost negligible because they only use 5V rail, and my 2.5 inch Kingston A400 480GB SSD only use 5V 1A (5W).

[LukeSavenije]

second PSUs are generally only a thing with for example XOC or in servers in case one of them fails. but otherwise it's not that common or in some cases even recommended to do

[Juular]

I pretty sure that at the point when you'll need a second PSU to power more drives, you'll run out of the place for them in your case in the first place, assuming your primary PSU isn't a complete shit.