How to work out how much power a NAS will use?

[DannyBoy1]

Hi,

I was thinking of buying a rack mount 12 bay ReadyNAS and wondering how to calculate how many amps it will use with 12 disks in it?

The NAS is "Netgear ReadyNAS 3220 2u 12 Bay Rackmount NAS" and I'm looking at putting in something like 12 x WD Red Pro 8TB.

The WD Red Pro's use 7.2 WATTS while reading and writing.

How do I calculate how many AMPS will be used with all 12 disks going?

Thanks

Dan

[StephenB]

>>> How to work out how much power a NAS will use?

Watts are power, amps are the current.  Summing the amps used for the various components in the NAS won't give you a useful result, since the components are using different voltages (and the main circuit is at yet another voltage, and is AC).

If you are wanting to know amps to size the circuit needed, then you could use the 550 watt spec for the power supply in the NAS. Then use P_(W) = PF × I_(A) × V_(V)  (solving for I).  I don't know the power factor for the PSUs used in the 3220, but 0.70 is a conservative value for PF.  At 110 volts, that gives you ~7.15 amps.

Typical power use would much less than 550 watts.  7.2*12 = 86 watts, plus the extra power needed for the system board and fans.  I don't know what the other components in the RN3220 need when the NAS is under load.  Maybe some other owner of a similar rackmount will chime in with their measured power use.