External drive caddy for 2 1/2 inch HDDs plugs into USB port.

[cobaka]

Hello all (incl @Andy Kay)

Regarding drives:

On eBay (where else?) I notice an external "caddy" for 2 1/2 inch drives.
In the photo below you can see one (of many) that are available.
These aren't lightning fast - but I find them convenient for portable "USB connected" storage.
I have no financial (or other) interest in these items. I just use them.
The drive (of course) must be purchased separately from the caddy.

2_1_2_inch_external_caddy(1).jpg (31.54 KiB) Viewed 156 times

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When I buy a drive to fit the caddy I always check the current rating. I try to choose a drive that draws 0.55A - and even this current demand is fractionally over the 500mA rating for a USB connector. However, few items actually draw the current load stated on the spec sheet - so I feel confident I'm not overloading the USB port.

I bought several of these caddies. These are convenient for back-up. (I only the Puppy 'save' file to save the operating configs.)
Mounting the drive in the caddy is a delicate operation. I always buy a metal drive, not a transparent (or plastic) item. I figure metal dissipates the heat better than plastic and isn't susceptible to static charge. When mounting the drive, take care to avoid contact between the drive card electronics and the metal case. Some suppliers provide small 'sticky-back' cushions to separate the electronics from the box.

That's all for this posting.
Hope others find these items useful.
You can, of course, just use a standard 'thumb-drive' in the USB port.
There are more ways to kill a cat than by drowning it in cream.

Cobaka.

[TerryH]

I have one of these clear plastic SATA caddies, which works fine. With an SSD in it, it's plenty fast for me. They are USB 3.0 interface. I haven't done any speed testing, but file transfer speed is excellent for me. I also have recently acquired an M.2 NVME external enclosure, which is USB 3.2 Gen2 10 GB/s, which I use as backup for my pictures from camera and phone. This drive is super fast.

[Federico]

This argumentation is not completely correct from a technical standpoint: in no way you can overload a USB port. The port will simply not supply a greater current than its allowed maximum.
The risk is not to overload the port, but not to supply the HDD with the power it requires, resulting in physical damage or bad operation.

Regarding the maximum supplied current of USB ports, USB 2.0 can supply up to 0.5 A (2.5 Watts @ 5Volts) and USB 3.x ports can supply up to 0.9 A (4.5 Watts @ 5Volts).

The USB protocol provides current as a multiple of "load units". 1 load unit is equal to 100 mA for USB 2.0 and 150 mA for USB 3.0. The USB 2.0 bus can supply a maximum of 5 load units of power (100 * 5 = 500 mA); the USB 3.0 bus can supply a maximum of 6 load units of power (150 * 6 = 900 mA).

In the unlikely case you are trying to use a very old USB 1.0 or 1.1 port (of a very old PC), it will not supply more than 0.5 Watts. So don't do it, because your HDD will for sure not work.

With that said, the power draw of a 2.5 inches HDD is not constant: it varies accordingly to what the drive is doing. This means that even if it starts up correctly it could run into problems and shut itself down abruptly later. The maximum power draw of a 2.5 HDD is usually not higher than 5 Watts. So it's important to know this value exactly before buying a given model.

This issue with maximum USB power can furthermore quite easily be solved by using a USB split cable like this one. When using such a cable, one could still somehow run into problems when using an HDD which draws more than 5 Watts and trying to supply it with power from 2 x USB 2.0 ports.

Finally, SSDs tend to draw less power than HDDs generally speaking, and one can also use 2.5 inches sata SSDs inside that kind of external enclosures.

[rcrsn51]

I have owned several USB hard drive enclosures, but they eventually fail when the fragile cable connection point breaks.

My preferred solution is a simple USB3-SATA adapter cable. Just plug it directly into the drive - no enclosure needed.

s-l1600.jpg (8.49 KiB) Viewed 57 times

This is a cheaper, more rugged method, particularly with SSDs. And you can use one cable with several drives.

[Federico]

Yes, in fact the picture I sent in my previous post is wrong, and shows exactly just a USB3-SATA adapter cable.
What I meant is something like this. Long story short: something which connects to 2 USB ports on the PC and to the given enclosure.
There are enclosures around which also provide an own included power supply. That solution is for sure less comfortable to move around but also so much safer for the data stored onto the drive.
To just use a USB3-SATA adapter cable is also a viable solution, but in that case the risk is to damage the drive by carrying it around, because normally it has exposed electronics.

A source of risk are also PCs with bad / old power supplies, which may fail to provide the USB port(s) with enough current (in that case, it's not the port(s) but the PSU itself to have been overloaded).