What PSU for 13 HDDs

[Deleted member 4644]

I am building a system with 13 HDDs. What size/type of PSU do I want for reliable multi year operation?

 

[Concillian]

HDDs don't pull a ton of power, except at startup. You want to find a data sheet like this:
http://www.seagate.com/docs/pdf/datasheet/disc/ds_barracuda_xt.pdf
for whatever drives you have.

Note that it has a startup current listed in it's table. This should be the maximum power draw for the drive. in this case, the 2TB drive is listed at 2.8A on 12v, or about 35 watts (x13 = 455 Watts) and the 3TB drive is listed at 2.0A on 12v, or about 25 watts (x13 = 325 Watts)

Startup is the only time they'll be pulling that much, and will be less during other cases. You need another 100W or so for the rest of your system, which will be near the idle power consumption when the drives are spinning up.

If you have a bios option for staggered spin up, then you can reduce the need further, as they won't all be pulling peak power at the same time. You can see in that data sheet, operating power is more on the order of 10W and idle 7-8W vs. the 25-35W startup power. So staggering could reduce your need to be able to use a more modest power supply.

I would find the data sheet for the exact drives you're using. There is a fair amount of variation between drives. Some spinup slower to keep max power draw low, some spinup fast with more power draw, drives with more platters draw more power at spinup, etc... You can see how much variation there is from the spec sheet I linked... the 2TB drive draws significantly more power at startup than the 3TB drive, which is not something that would be intuitively obvious. You need the spec for your exact drive.