PC +/-5volt +/- 12volt triggered start power supply?

[Daveis]

Ok, I think this is the place to ask this.

I am running 8-12 hard drives on my PC. I've found that no matter what I do the 400-600 watt consumer power supplies I've tried can't reliably handle the startup demands of the drives. I believe that the problem is that the drives each pull 30watts x 12 on startup and the power supplies I'm usng cant deal with it.

If I warm restart the PC, usually the drives come up ok and are recognized by my array controller.

It's a real pain using a RAID5 array and having some of the drives not spin up in time. The array controller thinks that some of the drives in the array have failed, but in fact it's just a turn-on surge timing issue.

How do I solve this? My controller supposedly supports SATA staggered startup. So I think it's more a problem of the power supply handling the spin-up demands of all the drives.

Any ideas on a small power supply design that I could use?
Ideally it would be triggered from the startup of the main power supply.

I've tried using a second PC power supply with dummy load, but that doesnt work. There is apparently a small window of time between the drive controller recognizing that the main power supply is running and when the drives spin up. Applying power to the drives BEFORE turning on the PC/main supply doesnt work. And I wish I knew why....


I don't really want to have to spend $1000's on real server grade hardware from Dell/HP/etc. just to have 8-12 drives in a PC running reliably.

[Zen Mod]

try with additionall one or two PSes for hards ,but bridge green wires (Power good sense) between them and master PS unit;
also bridge few blacks

you don't need dummy loads for additional PSes -HDDs are more than enough dummy for that

[Daveis]

The green power good sense on an ATX supply is set by the motherboard or the power supply? (which device is signalling the other)

I'm trying to understand the sequence of events that happens when I push the power button on the PC.

It's really ok to bridge two power supplies? They wont "fight" each other.

[Zen Mod]

ups-my mistake....
but just with name....green wire on power connector for mobo is PS ON , not power good...
but-anyway-when you make short between green and any of blacks,then this short will power up that PS....exactly same happens when you hit powe button on case

with bridging blacks between PSes,you put them all on same ground potential;
after that-you just bridge greens between main and all aditionall PSes;
main will drive mobo and few HDDs,and aditionall PSes can drive rest of HDDs.....
I hope that it will work