How many hard drives with the EA380?

[Dangman]

Hello,

The power supply in my Linux went south on Friday. Later that day I bought a Earthwatts EA380 380W PSU from newegg for $32. Right now here are the specs of my 'nix server:

Pentium III 866Mhz
Intel Mobo with onboard video
2 x 256MB PC133 RAM
1 x 40GB Western Digital HDD
2 x 120MM Yate Loons.

So I plan on adding more hard drives to my server for backup purposes. So now my question is: How many more hard drives can I add to my server with the Earthwatts 380W for safe operations? FYI, the EA380 has 27A on the +12V rail.

Thank You for your help.

 

[tazeat]

Probably around 10~20 depending on how many watts that system is using... Hard drives typically use around 7~8 watts afaik.

 

[maddude]

If you're going to be putting that many hd's in there, take into account start up, which draws around 25 watts, and i think 3-4 amps. If you have a raid card that supports staggered spin-up, this would be a good time to use it.

 

[Dangman]

I won't be using a RAID card. I'll just be using a simple IDE Controller PCI card. I have several IDE drive lying around and I want to put them to good use.

That's 3-4 Amps per drive at start-up correct?

 

[Farva]

It's more like 2-3A draw per drive on startup.

 

[Dangman]

Ok I just remembered that I posted the power draw with a Kill-A-Watt of my linux server a few weeks ago in another thread. Here it is with the same specs as I posted earlier:

64W at bootup
42W at idle
44W during regular file downloads
48W during torrent downloads
58W when downloading files straight from the server
53W when downloading files via Shared Documents/My Network Places

So assuming that all that wattage is on/from/using the +12V rail, that leaves me with 260W or 21A left/available on the +12V rail. And assuming 3A per drive on start up, does that mean that I can put up to 7 extra hard drives with the Earthwatts 380W with no problem? Or should I drop down to 5 extra drives to make sure that power supply isn't too stressed all the time?