Parallel second psu to power SATA devices question

[Ballardian]

I'm in the process of building a new home server but I ran into a problem AFTER I bought all the parts and I'm trying to salvage the project.

 

The goal is to build a single room apartment, small and low powered, OS on m.2 drive, up to 4x 2.5" HDDs for data storage, slim line optical drive included server, nas, and occasional HTPC/light gaming rig. Running in Windows 10 as base OS. 

 

I bought a GigaIPC v1605b motherboard which is an industrial board with a single on board SATA connector and a SATA power connector.  I bought a 2 port mini PCIe card to give me 3 SATA ports today to leave open the PCIe slot in CASE I want to put a dual slow low profile graphics card in. I had spec'ed out a SFX PSU to use in the SilverStone ML09 case I'm building this in. The v1605b board runs off of a ATX12V power supply ONLY which at the time I thought was great -- no 24 wire harness in the tight case. BUT I realized that without an ATX board the PSU will not 'come on' due to the 'Soft On' pin not being grounded.  I know I could just jumper the pin and off I go but one main way my server for my needs run is that it goes to sleep 95% of the time -- it is an on demand setup.  I don't want all the HDD's being powered while the board is asleep.

 

I also planned to run a slim line optical drive (for the random times I need one in a year -- I've found my current 'networked' optical drive handy at times) and I'd like to be able to run up to 4x 2.5" HDDs.  I'm going to start with 2 but I would like the option today to run 3 in case I need to swap one out of the drive pool in Drive Pool.  

 

While the mb with the mini pci-e card will have 3 SATA ports I'm concerned about running all the power through the one SATA power port on the board (I realize I'll need to add another card for the 4th HDD but that is easy compared the power issue that is coming). Gigabyte doesn't recommend more than 1 device on it. And with 2.5" drives drawing less power than a single 3.5" drive I could run 2 devices... but not 3 or 4. Or the optical drive as well.

That is the current dilemma I'm working myself out of. How to get power for 4-5 SATA devices that turn on/off in sync with the motherboard as it goes to sleep and comes on.

 

I also have internal USB 2.0 headers to work with. I'm now planning to use one of those to run the optical drive internally b/c it is most likely the most power hungry of the bunch. My plan is to run it off of a internal USB 2.0 port for 2 reasons -- 1) It frees up a sata port for another HDD/SSD (making the need for a larger card one more drive away) and 2) It helps reduce the power I need for devices.  

 

So here is where my idea/questions come up.  I was considering running a picoPSU in parallel with the board power. So 12v comes into the case, gets split, 1/2 goes to the board and 1/2 goes to a picoPSU to power SATA devices only.  This however runs into the same original issue of if I jumper the picoPSU the SATA devices will run all the time.  My goal is to find a way to communicate between the mobo and the picoPSU.   Here is what I've come up with and my questions about the idea:

 

• Using a USB port to indicate the power state of the computer.  If it is in sleep, standby, or off there should be no power on the 5V rail (if it isn't an always on port) and if the computer is running the 5V rail should be powered.  
• Connect the 5v rail with an appropriate resistor to one side of an optoisolator with the other side of the optoisolator connected between the GND and 'Soft On' pin of the picoPSU.

 

This in theory means as SOON as the USB port gets power the picoPSU is powered on and the SATA drives come alive. And when the mb cuts power to the USB port the picoPSU will shutdown the SATA drives

My main question here is basically is that a safe enough way to power up/down SATA drives that are data only. Do motherboards power USB immediately upon post for the SATA drives to be detected split seconds later?  And when motherboards shut down to the USB port power turn off late enough to be safe?  And what about sleep and hibernate?  Do USB port power do the same as SATA power in this instances? And what does SATA do in standard Windows sleep / hibernate situation?

Any insight would be greatly appreciated.

[Dutch_Master]

You may want to investigate the use of an external power brick and have an internal power distribution PCB, a bit like laptops do. Possible candidate here: click.

 

HTH!

[Ballardian]

2 hours ago, Dutch_Master said:

You may want to investigate the use of an external power brick and have an internal power distribution PCB, a bit like laptops do. Possible candidate here: click.

 

HTH!

I had looked at those style distribution board and got the impression the same issue applies: that without the atx switch toggled by the motherboard via 24 pin atx header the only other option was power all the time to all devices. Which is what I'm trying to avoid. No reason to have drives spinning 24/7 if nothing else is on to access them. 

[Dutch_Master]

Oh, I see what you mean. Well, if drives aren't accessed, the OS spins them down automagically.

[Ballardian]

3 hours ago, Dutch_Master said:

Oh, I see what you mean. Well, if drives aren't accessed, the OS spins them down automagically.

If the OS is off / motherboard is off/sleep do the drives stay spun down? 

[Ballardian]

My other thought this morning is that 2.5" 4TB externals can be powered over USB 2.0.  Does anyone know of a quality cable that could power up to 4TB 2.5" HDD while still allowing me to use the SATA data port instead of a USB data port?

"Like" this:

https://www.amazon.com/PCI-eCard-Extender-Extension-Cable-Powerful/dp/B0184ZQDA8/ref=sr_1_6?dchild=1&keywords=usb+to+sata+power&qid=1608998589&sr=8-6

 

My concern with this exact one is it appears to be straight wired between the USB and SATA port -- does that provide enough power on a single usb plug to run a 15mm 2.5" drive?  I believe the USB 2.0 specs say maximum of 500ma with negotiation though I've read that ports today can provide much more though I'd still expect to need a negotiation to get higher power out of a port.

My internal USB ports are only 2.0 which is why if I could power it off the USB port and send data to SATA port it would be an ideal solution.

[Dutch_Master]

1 hour ago, Ballardian said:

If the OS is off / motherboard is off/sleep do the drives stay spun down?

Yes.

 

1 hour ago, Ballardian said:

Does anyone know of a quality cable that could power up to 4TB 2.5" HDD while still allowing me to use the SATA data port instead of a USB data port?

No, external drives are powered as well as send their data via the USB cable.

 

IMO you're making it way too complicated in your head. Using splitters for SATA power is fine, most modern drives don't use nearly as much power as the early ones, especially SSDs are very efficient.

[Ballardian]

4 hours ago, Dutch_Master said:

Yes.

 

No, external drives are powered as well as send their data via the USB cable.

 

IMO you're making it way too complicated in your head. Using splitters for SATA power is fine, most modern drives don't use nearly as much power as the early ones, especially SSDs are very efficient.

If I was running off a normal PSU I would totally agree with you. The challenge is that I'm running off a mini-ITX built in power delivery system and I can't get specs on how much power it can handle.  I tried to get a better idea from the manufacturer and they just told me "1 SATA drive" but didn't answer my question of how much amperage I can run through the board.  In probable theory 3x 2.5" drives would be fine and maybe only the startup spike would be to much.  Right now the plan is 2.5" spinning 9mm disk with an 1 TB SSD.  What I'd want to put on there is a 4TB 15mm drive which does have a higher startup power.

Really, my concern is frying the board by running to much current through the SATA power.  Its an embedded board so proc is soldered to the board and if I fry it .... server over. And I just spend 1k on all my parts.  So I'm extra cautious.

So in some ways I'm making it extra complicated but I'm also trying to get an understanding of what is the safest method.  If I could get a spec out of Gigabyte of how much current that port could handle with the built in DC distribution.... I'd totally go for it.

[Ballardian]

4 hours ago, Dutch_Master said:

Yes.

 

No, external drives are powered as well as send their data via the USB cable.

 

IMO you're making it way too complicated in your head. Using splitters for SATA power is fine, most modern drives don't use nearly as much power as the early ones, especially SSDs are very efficient.

And I appreciate your ideas, information, and even pointing out it seems extra complicated to me.

 

I'm encouraged to push back on Gigabyte and see if I can get a current spec out of them. That really is the key. I don't need much and if they can tell me the max current I can draw from that port I can make an education decision. Thanks for that push.

 

[Ballardian]

On 12/26/2020 at 9:31 AM, Dutch_Master said:

Yes.

 

No, external drives are powered as well as send their data via the USB cable.

 

IMO you're making it way too complicated in your head. Using splitters for SATA power is fine, most modern drives don't use nearly as much power as the early ones, especially SSDs are very efficient.

Thankfully the manufacturer actually answered my question and gave me the specs for the 5V rail for the onboard SATA power connection.  It is much lower than most PSU's but workable for me.  I have 3 SATA ports and I can run 3x SSDs or 2x SSD + 1x 2.5" HDD, and MAYBE 2x 2.5" HDD.

Surprisingly, 2.5" HDDs don't use that much more power than 2.5" SSDs -- maybe an extra 300ma during R/W.  The real limiting factor is the startup current needed which doesn't exist on SSDs at all but the 2x spinning disk are between 1A and 1.2A.  I've been reading all the spec sheets in detail for my drives and board. I couldn't have maxed out my setup with 3x 2.5" drives on the rail without going over spec - now that I actually know the spec.