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Xymox
12-29-2011, 10:46 AM
I currently have 3 internal SATA drives (1 SSD, 1 HD, 1 CD-DRIVE) connected via their own individual power cable to the PSU. I was wondering if I could daisy chain them together. Or maybe connect 2 of them off the same power cable. Is this ill-advised? If so, why or why not?

komondor
12-29-2011, 11:17 AM
Depends on your power supply, is it a single rail are all the connectors coming off the same rail.

Long story short probably not but it also depends on what else you have in your system, 2 video cards with molex connectors, a motherboard with molex or what all devices in the system along with PS model can give you an exact answer. As long as your are going to daisy chain just to clean stuff up vs adding more you will probably be OK

Xymox
12-29-2011, 11:22 AM
Depends on your power supply, is it a single rail are all the connectors coming off the same rail.

Single rail. CORSAIR HX 750watt (http://www.newegg.com/Product/Product.aspx?Item=N82E16817139010)


Long story short probably not but it also depends on what else you have in your system, 2 video cards with molex connectors, a motherboard with molex or what all devices in the system along with PS model can give you an exact answer. As long as your are going to daisy chain just to clean stuff up vs adding more you will probably be OK

I only want to daisy chain to cut back on the amount of cables/clutter in the case. But I won't do so at risk to the failure of the components.

XReflection
12-29-2011, 11:29 AM
I currently have 3 internal SATA drives (1 SSD, 1 HD, 1 CD-DRIVE) connected via their own individual power cable to the PSU. I was wondering if I could daisy chain them together. Or maybe connect 2 of them off the same power cable. Is this ill-advised? If so, why or why not?

I'm not sure I see what the issue is. Don't SATA power cables generally have 3 connectors on them per cable? Is that what you mean by daisy chain? Since you have a single rail PSU, there shouldn't be a problem..

Xymox
12-29-2011, 11:30 AM
I'm not sure I see what the issue is. Don't SATA power cables generally have 3 connectors on them per cable? Is that what you mean by daisy chain? If so, then thats completely fine.

Yes, that's exactly what I mean. I just figured it was "better/safer" to not use all three connectors on the same cable to attach drives. Just my "fear" mindset I suppose...though why did I get a modular PSU and keep plugging power cables into it for every device. :)

XReflection
12-29-2011, 11:33 AM
Yes, that's exactly what I mean. I just figured it was "better/safer" to not use all three connectors on the same cable to attach drives. Just my "fear" mindset I suppose.

Nah, that shouldn't be a problem. If anything it would just cause something to be underpowered, but that would only be a problem if you have multiple rails. since its a single rail system, everything draws from the same rail and there is no need to balance components on multiple rails. I run 3 and 2 drives on two SATA cables on my PSU no problem and have been doing that every since I built my first computer.

prozac4312
12-29-2011, 11:33 AM
Yes, that's exactly what I mean. I just figured it was "better/safer" to not use all three connectors on the same cable to attach drives. Just my "fear" mindset I suppose...though why did I get a modular PSU and keep plugging power cables into it for every device. :)

The manufacturer wouldn't put 3 connectors on one rail if it wasn't safe to use all 3.

teetee1
12-29-2011, 11:39 AM
3.5" drives has max. power draw during drive motor spin-up stage and it only lasts a few seconds. After that the normal read/write action only consumes ~7W or less per drive. I think you can safely connect the SATA power connectors to the drives in serial fashion.

I do not think different physical 5v/12v power lines for drives from the same power PSU locate on different rails even if the PSU has multiple. It's different from the 6pin/8pin/4+4pin power lines with different color-coded wires for supplying power to PCIE and CPU/Motherboard. In other words all sata or molex power connectors should be on the same circuit/fuse.

Ref.
http://www.storagereview.com/guide/spinPower.html

larrymoencurly
12-29-2011, 11:55 AM
It won't hurt to daisy chain as many as 5-6 drives, unless maybe if they're all 15,000 RPM drives. Assuming 10 amps current draw and #20 wire (lousy power supplies use it), that's just 0.33V drop, but the crimp connections add a bit more voltage drop. A drive might draw 3 amps during the first 3 seconds while it's spinning up.

The way to get the exact answer is by hooking some drives at the last connectors on the daisy chain and measuring the voltages at those connectors while the drives are doing lots of seeks.

LiquidRetro
12-29-2011, 02:25 PM
3-4 drives daisy chained with that power suply should not be a problem. Just don't go cray and do more with that one rail.

Xymox
12-29-2011, 02:29 PM
3-4 drives daisy chained with that power suply should not be a problem. Just don't go cray and do more with that one rail.

Understood. I won't do more than those three drives (SSD, HD, DVD R/W).

dude2000
12-29-2011, 10:48 PM
in a nutshell you are fine;
each chain can hold 5A or 6A on wire, I don;t recall specs for power supplies (5a - 6a on 12 v and 5a - 6a on 5v); just check hdd amps for spin up and normal operation