Please HELP: What is the max # of HDs this PS can handle?

I have a Dell PowerEdge SC420

I looked on the PS unit and it has:

MODEL NO: PS-6311-1DFS

DC OUTPUT 305W

+5V === / 22A MAX
+5V(FD) === / 2A MAX
+12V - A === / 18A MAX

-12V === / 1A MAX
+3.3 === / 17A MAX
+12V - B === / 18A MAX

COMBINED POWER ON +3.3V AND +5V NOT EXCEED 150W
COMBINED POWER ON +12V-A AND 12V-B NOT EXCEED 264W
MAX. CONTINUOUS TOTAL DC OUTPUT POWER SHALL NOT EXCEED 305W


Image: http://www.ingearx.info/temp/My_20Dell_20PowerEdge_20SC420_20PS-6311-1DFS_1_.jpg

I looked at the hard drives and they are:
Seagate: (I have 4 of these)
+5V 0.75A
+12V 0.35A


Maxtor: (I have 6 of these)
+5V 740mA
+12 1500mA


Leading out of PS:
cord with: 2 SATA power connectors
cord with: 1 PATA and 1 for floppy drive
cord with: 1 power connector w. 6 sockets (5 have connectors inside) and 2 PATA power connectors

I also placed 3 PCI IDE expansion cards in the server.

My question is - what is the proper way to do the math to find out the maximum number of hard drives that the PS can support?
And do you think it is safe to plug all of those 10 hard drives that I have?

Thank you all very much...
4 answers Last reply
More about please help handle
  1. Well your #1 limiting factor is going to be the # of hdd bays in that chassis, according to Dell's info page it only has 2 non-hot-swap bays... Also you didn't mention your specific config like Celeron or P4, amount of memory and other options like embedded raid, etc. Best bet, go to the Dell support page, plug in your service tag, and post all your system specific details it will help us help you.

    BTW nice details on the hdd's here is the wattage for that:

    3.75w+4.2w=7.7w per seagate *4 = 30.8w

    3.7w+18w=21.7w per maxtor * 6 = 130.2w

    161w total hdd power consumption, if you can mount them that is 8)
  2. If he can get thru the boot process with all of those things spinning up, then he'll be okay...
  3. Thank you all for your help support.dell.com gave odd asp .net error...

    So manually my specs are:
    P4 2.8GHz, 2x512MB RDRAM, no video card (but AGP slot is present), 3/3 PCI slots have PCI IDE cards, 1 DVDRW drive that is it;

    The rest - I want to hook up as many HDs as I can... what do you think?

    http://www.extreme.outervision.com/PSUEngine estimates I can have 9 HDs - but look at the #of Watt difference in consumption of Maxtor and Seagate...
  4. How did you get 9 hdds? Here's what I got with the default 2 hdd setup:

    PSU calc"]System Type: Single Processor
    CPU: Intel Pentium 4 B 2800 MHz Northwood
    CPU Utilization (TDP): 100% TDP

    RAM: One Pair Rambus RDRAM
    Video Card: 32MB or Less AGP/PCI Basic Video
    Video Type: Single Card

    IDE HDD 7200 rpm: 2 HDDs

    DVD-RW/DVD+RW Drive: 1 Drive

    PCI IDE Controller Card: Yes
    PCI IDE RAID Controller Card: Yes
    Additional PCI Card (avg): 1 Card

    Fans
    Regular: 3 Fans 80mm;

    Motherboard, keyboard and mouse: Yes

    PSU Utilization: 100 %

    Total: 257 Watts



    © 2004 - 2006 OuterVision.com and it's licensors. All rights reserved.

    Not sure I would be comfortable loading it up any further... One idea would be to get a cheap (but decent) PSU just for the HDDs like this
    SPARKLE FSP250-60ATV ATX 250W (it's under $30, good quality components, not the greatest efficiency :cry: ) and dedicate it to all your hdd's and connect it like this to have it sync the power up:

    pc-mod.com"]

    Make sure to check the pinouts on the dell first :wink:
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