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JonathanM

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Posts posted by JonathanM

  1. 3 hours ago, kakburken said:

    nervous about if the 12V+ 999.6W is enough to handle the spin-up.

    It's plenty. That rating is for continuous use, and spin-up is only a very short period of time. Good quality power supplies handle peak loads even above their continuous rating, so that supply will give you a margin of safety even as it ages. 

  2. 42 minutes ago, kakburken said:

    Ok, well seems the Corsair RMx 1000W ships with three such cables. And if I’m wrong I have checked with their support and it’s possible to buy more from them. 
     

    https://www.corsair.com/us/en/p/pc-components-accessories/cp-8920112/type-3-flat-black-peripheral-cable-with-4-connectors-cp-8920112

     

    Sounds like you have a plan!

     

    4 pin splitters and extenders are ok, but not ideal. The fewer connections to get loose or corroded the better. If you can power everything with just the PSU connected cables that is the best option.

    • Upvote 1
  3. 3 minutes ago, kakburken said:

    Do you mean i can just buy whatever molex cable i want that has the same connector that fits in the PSU? (whatever that connection is)

    NO!!!!!

     

    You need to reach out to Adata tech support (or whichever PSU you land on) and get the correct cables. You need 2 more identical to the single molex that comes with the PSU.

     

    If that isn't possible or otherwise unlikely, then you will need to educate yourself further on WHY I said what I said earlier, so you can use third party cables safely. It involves checking pinouts, verifying voltages, testing for correct function BEFORE plugging any hard drives into the suspect cables.

    2 hours ago, JonathanM said:

    Modular power supply cables are NOT always interchangeable, sometimes they are, but the consequences if they are not is catastrophic to any attached hard drives. Make sure the power supply you choose either comes with enough connections out of the box, or has availability of the appropriate cables.

     

     

  4. Molex / SATA cables should all plug in to the same form connector on the PSU, typically they are just labeled HDD or something like that.

     

    Since the PSU you posted comes with 3 total hdd cables, 2 sata and 1 molex, you should be able to order a couple more molex cables and plug them in to the PSU, giving you 3 sets of power feeding your drives. More connections to the PSU = less electrical stress on each connection. You want to divide the load up as evenly as you can across as many wires as you can.

     

    Imagine you need to power 6 space heaters. If you plug all 6 into a single power strip plugged into 1 wall outlet, at best you will trip a breaker, worst case you burn the outlet inside the wall. You would want each heater to have its own outlet, with as short a cord as possible.

    That scenario is an extreme version of what's going on with your drives.

    • Upvote 1
  5. 6 minutes ago, kakburken said:

    one cable that has 4 molex on it?

    exactly, but the spacing isn't likely to match up perfectly with your case.

     

    6 minutes ago, kakburken said:

    Not sure if its 3x for every 12-way (so a total of 6x molex) or 3 in total though. but my guess is that its 3 total.

    3 connectors for 24 drives isn't likely. Probably 6 that need connections.

     

    Looks like that specific PSU has 3 connection points for hard drives, so you would want to source 2 more molex style cables for that specific unit and plug each cable into both 12 way bays, so both bays would have power from all three PSU hard drive power connections.

     

    Don't even think about trying to run all 24 drives from a single drive power cable.

     

     

  6. 2 minutes ago, kakburken said:

    Just choose the cheapest ones. 

    Sure, I'll just throw one more wrench at you.

     

    Look for the number and layout of hard drive cables that come stock, along with the ability to source more for the specific model if needed.

     

    Modular power supply cables are NOT always interchangeable, sometimes they are, but the consequences if they are not is catastrophic to any attached hard drives. Make sure the power supply you choose either comes with enough connections out of the box, or has availability of the appropriate cables.

     

    I'm assuming (perhaps wrongly, but you didn't say) that for 24 drives you are using some sort of backplane arraignment that should make cabling easier, but it would suck to buy a PSU and find out that you can't connect your drives because of a lack of proper cables.

  7. 35 minutes ago, kakburken said:

    thats a lot of different 12V that i have no clue on which of those i need to look at.

    Since it's single rail, the only number that matters is the 183.33A.

    24 drives X ~3A is around 75A worst case on the 12V hard drive feed. 75A x 12V = 900W.

    So, that PSU would have around 150W left available for motherboard, CPU, video and fans during a worst case power demand event. Realistically, that 900W hard drive number will probably never happen in real world, so it should provide plenty of power even when it's a few years old and has some wear on it.

     

    So, using back of the napkin rough math, that PSU is a very good candidate.

  8. 4 minutes ago, kakburken said:

    You still make it sound like if I choose a single-rail I don’t have to check all the details about 5V/12V and just choose a PSU with +900w and it will work fine

    As long as it's high quality from a good brand, sure.

     

    Narrow down your choices to the few that are actually obtainable in your market, and find the tech sheets for those specific supplies. Look for the power rating on the 12V section. Comparing several different models with the same overall rating, choose the one with the higher 12V capacity.

    • Upvote 1
  9. 16 minutes ago, kakburken said:

    found nothing about 5V.

    https://www.seagate.com/www-content/product-content/enterprise-hdd-fam/exos-x18-channel/_shared/en-us/docs/100865854d.pdf#G4.830176

    16 minutes ago, kakburken said:

    the spin-up was the moment when the most amount of power was used and you "had" to choose a PSU that could handle that amount of wattage, if i dont want to use staggered in unraid. 

    Correct, but the limiting factor is typically the 12V draw, and the PSU total power is all the different voltages combined. When you look at the full spec sheets on a PSU it will list the limits of each voltage separately, as well as the combined total, which is less than adding up each separate feed because they share parts.

     

    Part of the issue with communicating all this, you are asking questions that require at least some electronic engineering knowledge to explain the answers. I know you want a simple "how do I know this will do what I want" type of answer, but it's way more nuanced.

     

    Some PSU's are designed for heavy draw from the CPU, motherboard and video cards, while neglecting storage. Others provide more balanced output. To figure out which is which, you really have to get into the weeds with the PSU tech specs.

     

    12 hours ago, JonathanM said:

    Single rail means you have less homework to do when researching a specific PSU.

     

    That is the broad generalization glossing over all the nitty gritty details.

     

     

  10. 4 hours ago, kakburken said:

    the HDDs draws 749w at spin-up

    That sounds like total power, if you look up the specific drive model it should give both 5V and 12V power figures. Typically the 5V inrush current is relatively small, most of the power is needed on the 12V line.

     

    4 hours ago, kakburken said:

    Not that I know which line is for HDD

    If the manufacturer provides that information it would be in the full technical specifications.

  11. 40 minutes ago, DarB said:

    How would it fight it? Do you mean that they are not moving air in opposing directions (Sorry if this is a stupid question)?

    If the disk enclosure fan is pulling air into the case, all other fans should be pushing air out of the case, and all passive (non-fan) openings should be taped off.

     

    You want all the air moving through the case to be forced over the hard drives first.

  12. Single rail means you have less homework to do when researching a specific PSU.

     

    The PSU you choose must be capable of supplying the needed amps for 12V and 5V on the lines used for hard drives.

     

    Multi rail means full rated current may not be available on the hard drive supply lines, so you must find the current rating for hard drive connections specifically. Part of the rated current may be dedicated to video card supply lines. Doesn't mean that PSU won't work, just means you have to find the specifications for the individual rails.

    • Upvote 1
  13. 10 hours ago, Convington said:

    what I did wrong with the mapping

    It's not usually the mapping that is the issue, but the settings inside the application not pointing to the mapping. If sab is putting downloads somewhere besides /data, that would do it, also if the 'arrs aren't moving it to /media, that would do it as well.

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