Number of disk to psu output?

[QWeelon]

Hello!

I've just installed a new controller card to connect additional disks, so far it works like a charm, however it does seem that I'm a short on power cables from my PCU to four of my newly connected disks. These disks are also furthest from the PSU, so the cables need to be slightly longer than the ones the were packed with my PSU (Corsair RM750x V2 750W).

I found one of these on Amazon which seems like a very simple and suitable solution.

What I'm unsure of is how many drives a single PSU Sata peripherals output can power, the original cables only connect to 3 disk, can I use the same output to power an additional 4 disks using the two splitter cables in the link above?

/Q

 

[ThreeDee]

You could also run something like this

Ystter 4Pin IDE to 5-Port Supply Cable 4Pin Molex to Multi SATA Port 18AWG Wire Cord For Hard Drive HDD SSD PC : Amazon.se: Elektronik

Ystter 4Pin IDE to 5-Port Supply Cable 4Pin Molex to Multi SATA Port 18AWG Wire Cord For Hard Drive HDD SSD PC : Amazon.se: Elektronik

www.amazon.se

 

[QWeelon]

Ok, not sure if I have Molex PSU cable lying around. But what I'm most curious is concerning how many disks I can supply through one single PSU output socket? Is there a limit? These disks are smaller, 3TB each, but I don't want to limit myself from upgrading in the future.

The PSU unit itself should have sufficient capacity to power my setup, just want to investigate if there is a limit to each socket. My PSU is modular.

 

[Alecmascot]

Are you missing some cables as it is modular ?
3 cables with 3 sata connections on each from the manual

 

[jgreco]

I use the same output to power an additional 4 disks using the two splitter cables in the link above?

No, you may not.

Please do review

Proper Power Supply Sizing Guidance

I've seen about 1,000 threads like this one where people decide that they can power a dozen hard drives off a 360 watt supply. DO NOT DO THIS. I've seen another 1,000 threads where people decide to buy the cheapest power supply that they can find. DO NOT DO THIS. Your NAS lives or dies by...

www.truenas.com

and note that SATA power connectors are NOT rated for more than a single 3.5" HDD. The result of running more than one is discussed over at

BUILD - Please review my Intel Skylake FreeNAS build

If you do want the SATA adapters, get crimped not moulded ones. GOOD BAD

www.truenas.com

where you will note that the main connector has burned and one of the secondaries has melted, probably damaging the HDD at the same time. HDD warranties will not cover physical damage in most cases. So, the short answer is, no, do not do this.

You may need to contact the PSU manufacturer to find out what their recommendations are. In some cases, they may have a special cable available that will add a fourth HDD, but this is likely to be a replacement for the entire cable. The main issue here is startup current. This is all discussed extensively in the PSU sizing thread.

 

[Ericloewe]

and note that SATA power connectors are NOT rated for more than a single 3.5" HDD. The result of running more than one is discussed over at

Well... It's closer to two disks per the spec, but the Super China Happy Sun Cabling Co. Ltd. factory doesn't seem to be very good at making SATA power connectors that don't melt when the specced 4.5 A are approached.

 

[jgreco]

It's closer to two disks per the spec,

Running connectors "at spec" is a great way to ensure they fail. Of course everyone who has read the Power Supply Sizing guide knows I'm all about the derating. The connector was only ever intended to run a single drive, as far as I know, so I suspect the designers also believe in derating. They had to have predicted cables by today's Most Awesomely Sarcastically Named Fly-by-Night Company Name:

Super China Happy Sun Cabling Co. Ltd. factory

Thanks for the laugh.

A high quality SATA power splitter would be fine for lower-power consumer SSD's though.

 

[QWeelon]

Sorry for probably asking some stupid questions, just want to get this right without ruining anything! :)

No, you may not.

Please do review

Proper Power Supply Sizing Guidance

I've seen about 1,000 threads like this one where people decide that they can power a dozen hard drives off a 360 watt supply. DO NOT DO THIS. I've seen another 1,000 threads where people decide to buy the cheapest power supply that they can find. DO NOT DO THIS. Your NAS lives or dies by...

www.truenas.com

and note that SATA power connectors are NOT rated for more than a single 3.5" HDD. The result of running more than one is discussed over at

BUILD - Please review my Intel Skylake FreeNAS build

If you do want the SATA adapters, get crimped not moulded ones. GOOD BAD

www.truenas.com

where you will note that the main connector has burned and one of the secondaries has melted, probably damaging the HDD at the same time. HDD warranties will not cover physical damage in most cases. So, the short answer is, no, do not do this.

You may need to contact the PSU manufacturer to find out what their recommendations are. In some cases, they may have a special cable available that will add a fourth HDD, but this is likely to be a replacement for the entire cable. The main issue here is startup current. This is all discussed extensively in the PSU sizing thread.

Lots to take in, but I think i got the gist of it. I did a rummage through my cable bag and found a 4 tier molex cable, which I'm considering to get a molex/sata adapter for. Got a bit worried after a quick google though, Molex to sata, lose all your data..

If you do want the SATA adapters, get crimped not moulded ones.

.

Could need som help translating that to what to look for when buying adapters, as the good example picture has a link error. Not sure what gimped/moulded (mould cast?) means?

At this stage, I want to connect an additional 4 disk, which I believe could be achieved through the connecting each of the molex connectors to a single sata adapter. Would this be a proper one? Pretty straight forward imho. But I have room in my case for an additional 4 disks and would like to prep my build for a future expansion.

Is it possible to splice each of the molex into a dual sata using an adapter similar to one above?

Or have completely missunderstood everything?

Money is not really an issue here, what is the best way to power my disks without changing PSU - I must say that I would prefer retailers in Europe. Worth noticing is that these disk are relatively far from the PSU so the cables that comes with the unit are not quite long enough.

I will consider contacting corsair for their input on how to proceed!

Thanks!

 

[jgreco]

probably asking some stupid questions, just want to get this right without ruining anything!

So, in other words, not actually asking a stupid question, but rather asking the question that I would much prefer be asked. The reason I write things like the Power Supply Sizing guide is that it is much preferable to do things right. Power is one of the things that can really totally screw up your system and ruin thousands of dollars worth of equipment if done wrong.

The problem here is mainly that it actually takes some work to track down all the details. Right now I'm a bit short on time and the Corsair website has some scripting on it our local firewall has blocked, so I'm having some difficulty in getting the manual. Google kinda suggested that there were several versions of this PSU anyways, which may have different amp limits on the various rails, so if you have an exact part number for this -- the current model seems to be CP-9020179-NA -- I suggest posting it. There seems to be an implication reading between the lines from reviews at TomsHardware that there are at least three versions of this thing. I couldn't find Google-fu for the "V2" quickly, and I'm already running late here.

 

[HoneyBadger]

RM750x V2 is the "2018" model - the "current" or "2021" is CP-9020199-NA

https://www.corsair.com/corsairmedia/sys_master/productcontent/RMx_2018_Manual.pdf

Docs show as 62.5A on the 12V rail - it's "theoretically able" to deliver 100% of its rated output on the (single) 12V rail alone.

 

[QWeelon]

So, in other words, not actually asking a stupid question, but rather asking the question that I would much prefer be asked. The reason I write things like the Power Supply Sizing guide is that it is much preferable to do things right. Power is one of the things that can really totally screw up your system and ruin thousands of dollars worth of equipment if done wrong.

The problem here is mainly that it actually takes some work to track down all the details. Right now I'm a bit short on time and the Corsair website has some scripting on it our local firewall has blocked, so I'm having some difficulty in getting the manual. Google kinda suggested that there were several versions of this PSU anyways, which may have different amp limits on the various rails, so if you have an exact part number for this -- the current model seems to be CP-9020179-NA -- I suggest posting it. There seems to be an implication reading between the lines from reviews at TomsHardware that there are at least three versions of this thing. I couldn't find Google-fu for the "V2" quickly, and I'm already running late here.

Very wise words, but I can also imagine that similar questions has been asked many times before.

Yes certainly.

According to my retailer, it's called CP-9020179-EU, so the european version of the one you listed, the same retailer also has the manual linked.

 

[QWeelon]

RM750x V2 is the "2018" model - the "current" or "2021" is CP-9020199-NA

https://www.corsair.com/corsairmedia/sys_master/productcontent/RMx_2018_Manual.pdf

Docs show as 62.5A on the 12V rail - it's "theoretically able" to deliver 100% of its rated output on the (single) 12V rail alone.

That sounds promising, at least in theory (if I understand correctly) - but what does it mean in terms of amount of disks to power in a socket, and how can I safely connect said disks to one socket, i.e. suitable cable config.

 

[HoneyBadger]

Apparently they're using 18AWG copper wires inside those modular cables. Even with a 750mm cable and assuming some more loss for the additional plugs (modularity + the converter) I'd imagine you can safely put at least five drives per cable without much concern. I'm not an EE though, so someone else might want to do the math about potential voltage droop and inrush current amount.