So I recently built a NAS at home here for file storage. I have 6 drives all in a row. I don't have a picture, but some guys have one "line" of sata power connectors that daisy link from one drive to the next to the next making it very clean and no slack in between each drive. Is there any where to get these or are they custom made? I don't even know what to search to find them.
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Sata power connectors.
- Thread starter /usr/home
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Something like this?
Most of those closely spaced daisy chains are custom made, you can DIY if you want. Some people have had problems with many in a row since the last drives may not receive proper voltage. I have not come across one that was more than 3 in a row that wasn't hand made probably for this reason.
Most of those closely spaced daisy chains are custom made, you can DIY if you want. Some people have had problems with many in a row since the last drives may not receive proper voltage. I have not come across one that was more than 3 in a row that wasn't hand made probably for this reason.
richardatkinson
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With too many drives connected you could potentially have an issue with the increased current draw. I believe most power supplies use 18ga wire which has a max 'safe' rating of 6 amps. This will give you 72watts max on the 12v and 30watts max on the 5v wire. Further research is required to determine the power draw of a hard drive under max current draw. (Probably cold start)
If this is the case, I would imagine one could make an adapter with two female molex connectors and some 16 ga wire would probably do the trick. 16ga can take up to 8 amps (96watts on 12v, and 40watts on 5v) without heating or creating excess resistance.
References: Googling max wire current for 18ga stranded.
http://www.doityourself.com/forum/electrical-c-d-c/69882-18-guage-stranded-wire-max-amperage.html#b
Also, to the poster above me:
In such a situation, all of the drives would receive a reduced voltage, not just the last one. However, the last one would theoretically receive the lowest voltage but only due to the extra few inches of wire. In a parallel circuit, the voltages to all devices are the same.
Edit: I've done some more research and this (http://ixbtlabs.com/articles2/storage/hddpower.html) article from 2005 has the results from some tests which were conducted. They found the startup draw to be 2.5A on a random Seagate hard drive! That's 30Watts! Now it makes more sense that you see wires with only two or three connectors on them. If you were to go with a 14ga wire you could start 6 hard drives simultaneously without exceeding the specs posted in that forum which I linked to earlier.
However, it is worth noting that it is safe to exceed these specs by a small amount for very short periods of time such as motor startup. I really don't have any figures but I'd guess 15-20% extra would be fine without heating the wire and creating extra heat, and thus increased resistance.
If this is the case, I would imagine one could make an adapter with two female molex connectors and some 16 ga wire would probably do the trick. 16ga can take up to 8 amps (96watts on 12v, and 40watts on 5v) without heating or creating excess resistance.
References: Googling max wire current for 18ga stranded.
http://www.doityourself.com/forum/electrical-c-d-c/69882-18-guage-stranded-wire-max-amperage.html#b
Also, to the poster above me:
In such a situation, all of the drives would receive a reduced voltage, not just the last one. However, the last one would theoretically receive the lowest voltage but only due to the extra few inches of wire. In a parallel circuit, the voltages to all devices are the same.
Edit: I've done some more research and this (http://ixbtlabs.com/articles2/storage/hddpower.html) article from 2005 has the results from some tests which were conducted. They found the startup draw to be 2.5A on a random Seagate hard drive! That's 30Watts! Now it makes more sense that you see wires with only two or three connectors on them. If you were to go with a 14ga wire you could start 6 hard drives simultaneously without exceeding the specs posted in that forum which I linked to earlier.
However, it is worth noting that it is safe to exceed these specs by a small amount for very short periods of time such as motor startup. I really don't have any figures but I'd guess 15-20% extra would be fine without heating the wire and creating extra heat, and thus increased resistance.
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Unless it's in a big brand desktop (where the OEM can order a PSU with cables just the right length to match their case) closely spaced connectors probablly means someone has made their own custom cabling. PSU vendors leave quite a bit of cable between connectors because they don't know how far apart drives will be in your case.
Short surges (e.g. hard drive spinup) won't cause significant heating in a cable even if they are significantly above the cables nominal rating. The bigger concern with loading to many drives on a wire is that volt drop may become unacceptable. Of course this depends on the length of the wire as well as it's thickness.
What you want for this sort of cable are the IDC style connector e.g. http://www.frozencpu.com/products/1...nnector_-_Black_-_90_M-SCA-16F-BK.html?tl=g51
Short surges (e.g. hard drive spinup) won't cause significant heating in a cable even if they are significantly above the cables nominal rating. The bigger concern with loading to many drives on a wire is that volt drop may become unacceptable. Of course this depends on the length of the wire as well as it's thickness.
What you want for this sort of cable are the IDC style connector e.g. http://www.frozencpu.com/products/1...nnector_-_Black_-_90_M-SCA-16F-BK.html?tl=g51
richardatkinson
Weaksauce
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If what you say is correct then the last connector would be essentially unusable due to decreased voltage regardless of the number of hard drives connected. When you're taking about a 12 to 18 inch length of wire, cold resistance is basically negligible at 6.29 milliohms per metre for 22awg.