Power needed for two 2TB hard drive (3.5" size)?

Hello,

I bought a dual sata-usb 3.0 adapter, came with 2A power supply, no problem to start with one of the HD however if i plug two of them most of the time it won't start totally (disk starts but one make strange sound cause not enough power to finish initializing)... Of course both drive are fine. Should i get a more powerful AC Adapter?

Thanks!

Does it matter which slots the drives are inserted in to? Having said that, it could well be a power problem. But why should you get a different adapter? If the adapter came with the dock, it should be capable of supporting the dock's full capacity. Unless, of course, the manual states that only a single disk is supported at any given time.

It would be useful to have the make/model number of this adapter to be able to check it out. What are the reviews like (if any), and have others been having similar problems with it according to their forum (if they have one) ?

Does the capacity of the HD matter? For example, 2TB HD require (much) more power than 1TB HD to be powered up? The actual adapter is bought on ebay from HK, it has no brand and i didn't see it sold on amazon (for example) so no reviews.

No markings at all anywhere? There shouldn't be any noticeable difference in power requirements between a 1TB drive and a 2TB one. What is the link to the eBay page in case I might be able to infer something from it.

Specs for Western Digital Caviar Black (high performance 7200RPM drives):

WD Black

2TB, read/write power 10.7W. 1TB, 6.8W. (I didn't expect that large a difference. The 4TB unit also only needs 10.4W.)

I don't know what a "2A" power supply means, exactly. (2A at 12V?) Is the USB adapter rated to be able to use more power than that?

There are no information on the USB adapter, only the wall plug. And 2A at 12V DC yes. To find it, type "dual sata usb 3.0" on ebay.com, sort by cheapest price+shipping and it's 1st resultat (~$22)! You can send the seller a message asking him if it's compatible with 2x2TB hard drive cause he's pretending it's not, while other sellers selling same item told me it is..!