Powering 12HHD's of one psu cable

[i3iorn]

So I have begun a diy project based on a heavely modified Fractal Design r4. It is going to be working as a NAS but the project is mostly because it sounded like fun. Anyway I have an idea to build 12 hot swappable bays for 3.5 or 2.5 inch drives taking up the entire front of the chassi. Due to fancy, cable management and cost I'd like to power all of the harddrives of one psu cable. Since all drives will consume less then most graphics cards I know it can be done but I suck at electrical engineering so I tried google and came up with nothing ( perhaps since I didn't really know what to google ) so now I turn to you guys.

 

If I could just get some ideas as to where to look for answeres that would be awesome. Best case scenario there is some kind of a converter I can buy somewhere.

 

So thank you in advance and have a good day.

[zMeul]

HDDs can eat up to 10W each - depends

 

in the worst case that cable will have to supply 120W - not ideal, I would split the load on two cables

[JeJaRaLa]

i think it depend more on the psu  the amount of power it can deliver to power  all the hdd, as above say put a good  cable too

[i3iorn]

My graphics card draws 230W of one 8-pin connector so 120W should be no problem as long as the PSU is good to deliver that kind of power. But SATA power doesn't come from an 8-pin normaly so I have no idea how much a sata power cable can draw from the CPU. I expect alot less since I have never seen a sata power cable with more then 4 connectors.

[zMeul]

13 minutes ago, i3iorn said:

My graphics card draws 230W of one 8-pin connector

the standard is 150W for 8pin connector

 

and if you already made up your mind, why are you asking?!

[meenmeen1103]

What power supply will be used?

[meenmeen1103]

2 minutes ago, zMeul said:

the standard is 150W for 8pin connector

It's likely drawing that 230W from the 8pin and the PCIE supplied power combined

[i3iorn]

19 minutes ago, zMeul said:

the standard is 150W for 8pin connector

 

and if you already made up your mind, why are you asking?!

I am asking if it is possible and meenmeen might just have explained tome why it might not be. I was just going from the stated power consumption of the specs and didn't take into consideration that it gets power delivered from two places. So I might have to use two cables as you said.

 

19 minutes ago, meenmeen1103 said:

It's likely drawing that 230W from the 8pin and the PCIE supplied power combined

You are correct I failed to take that into account.

 

But if you can get 150W out of the 8-pin it sounds to me like it would be possible to power 12HDD's of that cable? If so does anyone know how it can be done?

 

[zMeul]

18 minutes ago, i3iorn said:

But if you can get 150W out of the 8-pin it sounds to me like it would be possible to power 12HDD's of that cable?

the 8pin PCIe connector has 3 * 12V and 3 grounds - for each 12V you have one ground

while the SATA power connector has 1 * 12V, 1 * 5V, 1 * 3.3V and 2 * gorund - for each voltage wire you have less than 1 ground wire

[meenmeen1103]

15 minutes ago, i3iorn said:

But if you can get 150W out of the 8-pin it sounds to me like it would be possible to power 12HDD's of that cable? If so does anyone know how it can be done?

 

You can, you just need to solder up enough sata connectors to the corresponding 5v, 12v, and grounds for both to the main, say 8-pin, bundle. Not too complicated if using a multimeter. 

[i3iorn]

4 minutes ago, zMeul said:

the 8pin PCIe connector has 3 * 12V and 3 grounds - for each 12V you have one ground

while the SATA power connector has 1 * 12V, 1 * 5V, 1 * 3.3V and 2 * gorund - for each voltage wire you have less than 1 ground wire

I understand thats a problem but can you spell it out for me. Does it mean I would need a tranformer of some kind or just a question of splitting ground wires until I have enough?

 

What I naively imagined before I asked the first question was that I could draw one cable from the psu to some kind of a hub that would electromagicly turn that power into what the drives need and then run one cable with 12 connectors down the rack of drives. Can this be done without me making the "hub" cause that part is way out of my league. But I am pretty handy in general, built the actual drivecages myself with some spare parts and a 3d printer, so some general sauldering and splitting/mergin of wires is no problem.

[zMeul]

4 minutes ago, i3iorn said:

I understand thats a problem but can you spell it out for me. Does it mean I would need a tranformer of some kind or just a question of splitting ground wires until I have enough?

 

What I naively imagined before I asked the first question was that I could draw one cable from the psu to some kind of a hub that would electromagicly turn that power into what the drives need and then run one cable with 12 connectors down the rack of drives. Can this be done without me making the "hub" cause that part is way out of my league. But I am pretty handy in general, built the actual drivecages myself with some spare parts and a 3d printer, so some general sauldering and splitting/mergin of wires is no problem.

wait ... you want to build your own cable using off the shelf connectors?

 

you cannot use the PCIe as source because it only supplies 12V

[meenmeen1103]

47 minutes ago, i3iorn said:

I understand thats a problem but can you spell it out for me. Does it mean I would need a tranformer of some kind or just a question of splitting ground wires until I have enough?

 

What I naively imagined before I asked the first question was that I could draw one cable from the psu to some kind of a hub that would electromagicly turn that power into what the drives need and then run one cable with 12 connectors down the rack of drives. Can this be done without me making the "hub" cause that part is way out of my league. But I am pretty handy in general, built the actual drivecages myself with some spare parts and a 3d printer, so some general sauldering and splitting/mergin of wires is no problem.

You could have one 12v and one ground go to a converter (would have to be a step down to 5v somewhere around 10A and you'd also need a passthrough for the 12v ) then out to power all drives (I'm assuming no 3v is needed for the drives, and if it is then add yet another converter for 12v to 3v) but that seems like an unnecessary complication to something the PSU already does internally and adds one more component that could fail.

You never answered what PSU but I'm assuming modular. Just have two of the sata cables out from it and add connectors to have 6 on each. Should be plenty of power for all drives.

[Mr.Meerkat]

Or just use 2 sets of sata power cables no? (or even splitters...)

 

Something like this (I know it's linking to amazon UK but it's just an example) as why jerry rig cables to existing cables when you can just go with the simple route of getting splitters  

[i3iorn]

5 hours ago, meenmeen1103 said:

You never answered what PSU but I'm assuming modular.

Sorry I missed that http://www.corsair.com/en/rmi-series-rm750i-750-watt-80-plus-gold-certified-fully-modular-psu-cn

 

5 hours ago, meenmeen1103 said:

Just have two of the sata cables out from it and add connectors to have 6 on each. Should be plenty of power for all drives.

 

3 hours ago, Mr.Meerkat said:

Or just use 2 sets of sata power cables no? (or even splitters...)

 

Something like this (I know it's linking to amazon UK but it's just an example) as why jerry rig cables to existing cables when you can just go with the simple route of getting splitters  

 

Well since everyone say use two cables I guess I should use two cables. Was hoping to use the last 6pin on the psu for something else.

 

Still would be so much cleaner in the case with one less cable.

[alpenwasser]

11 hours ago, i3iorn said:

So I have begun a diy project based on a heavely modified Fractal Design r4. It is going to be working as a NAS but the project is mostly because it sounded like fun. Anyway I have an idea to build 12 hot swappable bays for 3.5 or 2.5 inch drives taking up the entire front of the chassi. Due to fancy, cable management and cost I'd like to power all of the harddrives of one psu cable. Since all drives will consume less then most graphics cards I know it can be done but I suck at electrical engineering so I tried google and came up with nothing ( perhaps since I didn't really know what to google ) so now I turn to you guys.

 

If I could just get some ideas as to where to look for answeres that would be awesome. Best case scenario there is some kind of a converter I can buy somewhere.

 

So thank you in advance and have a good day.

I run 12 SATA drives off a single cable in my server without issues, like so:

 

 

 

(Not all drives are connected in that pic, but I've tested it with 12 drives and it works without problems.)

 

What you need to ensure if you want to do this is:

1) Can your PSU deliver enough power on the connector at the right voltages?

2) Can your wires carry the required amount of current?

 

To answer the first question, you can check your drive or your drive's spec sheet, if you can find it. Sometimes manufacturers will indicate max power draw or max current draw. Most of the time I've only seen averages/typical values though, which aren't very useful.

 

11 hours ago, zMeul said:

HDDs can eat up to 10W each - depends

 

in the worst case that cable will have to supply 120W - not ideal, I would split the load on two cables

 

I think I've actually measured drives up to 25 W when powering up (it's been a while, don't remember all the details). Only for short amounts of time, of course, but still... Naturally there's a margin of error, power brick losses (it was just a watt meter -> AC/DC converter brick -> drive setup, not inside the computer), but I was pretty astonished. This was a 7,200 rpm desktop drive btw. Just thought I'd mention this.

 

Either way, this:

10 hours ago, zMeul said:

the 8pin PCIe connector has 3 * 12V and 3 grounds - for each 12V you have one ground

while the SATA power connector has 1 * 12V, 1 * 5V, 1 * 3.3V and 2 * gorund - for each voltage wire you have less than 1 ground wire

would seem to be the primary issue with this plan.

 

Basically: Yes, you can power 12 drives off a single cable, if your PSU and wires are up to the task. But that cable needs to provide the correct voltages, a PCI-E connector won't do.

[i3iorn]

Thank you for that. Where did you find a cable with 12 connectors or did you make it?

[alpenwasser]

7 minutes ago, i3iorn said:

Thank you for that. Where did you find a cable with 12 connectors or did you make it?

I took the original SATA power cable from the PSU, removed the original power connectors and mounted new ones in the needed number and spacing. Bought them from Lutro0's store if I remember right. You can probably pick them up at other modding stores or eBay as well.

[i3iorn]

Thank you all for your time and help I feel a lot wiser then when I woke up this morning. I will start with using two cables to be safe and do some testing on a power supply I have lying around to see how much power I can draw from one 6pin by just adding connectors.