Power 3.5 HDD 12V?

Question

Electronics

After the end of the PC era in my house and the full transition to laptops, there was a farm of large 3.5 hard drives idle. I want to start them up as external storages. I bought a fast SATA3->USB3.0 converter, 2.5 screws eat from 5V, but for large ones - there is an external 12v power supply input. I want to take these 12v not from a separate PSU, but to "pull" from the 19V PSU of the laptop itself, that is, both the laptop and the HDD will eat from one PSU without occupying extra sockets, the PSU has a supply. What is the best thing to do: quickly dilute a linear stub with filters from the 78L12 series (ampere) on a textolite, or take a DC-DC-lower also of the corresponding amperage? The question is in the efficiency and quality of the constant at the output of the two options, thoughts are interesting

Answer 1

Definitely pulsed DC-DC, otherwise it will be necessary to collective farm the radiator more than the power supply.
The quality of the power supply should not hurt you much, because in the computer 12V is also from a switching power supply. (well, within reasonable limits :))
At the start, it will be necessary to have 15-20 watts, which would also withstand 10 watts during operation. (well, maybe with the features of a particular disk)
In principle, you can make a good tee in which there will be an input socket for charging; DC-DC up to 12V @ 2A with an output to the HDD from a stub of wires from an old power supply; 19V output with laptop connector.
Just in case, look at the consumption of the laptop from the power supply, if there is a reserve. Well, or it’s stupid when working with a hard drive to be powered by a power supply unit, and the laptop will be on batteries at that time.
If you order something from Chinese comrades, thendivide the promised power by 3-4 if you do not want self-soldering Schottky diodes or the installation of fans. :) And first, drive this PSU on a load longer, look at its behavior.

Answer 2

Thoughts - what other thoughts? The efficiency of the linear stub 12/19 = 60%, the impulse one is higher, the quality is the same, the textolite is superfluous, the snot rules, the era is over.

Answer 3

How best to proceed

do not feed the screws from the power supply unit of the laptop.
And saving on sockets is, excuse me, generally from the category of idiocy.

Answer 4

But why did you decide that the power supply from the laptop has a reserve? In fact, it will most likely be enough for an additional screw, but still saving sockets in this case is a perversion!

Answer 5

buy nas without the included screws based on features and budget. all the advantages of just a hard drive with power on the shelf are imaginary and do not hold water for a long period of time.

Answer 6

Your best bet is to buy a nas or build on x86 using Xpenology or similar software. Everything else is the Krasnaya Burenka collective farm.

Answer 7

• First, thanks for the reminder, I completely forgot that the pancake motor still needs to be unwound, that is, even if we have <0.5A at 12V in operation, we still need to give a couple of amperes to spin up (78L12 1A stub is no longer an option, it will be overloaded and boil) . In the evening I will actually measure the starting currents, but I will still do it on a ds-ds lowering.
  (cheap, cheerful and not redundant, it will suit me completely for occasional use. ps The laptop is template, it will not be a macbook)
  Thanks to all!