What power adapter shall I use?

On the My Cloud EX2 Ultra manual (p.101) it’s said that If I’m adding two 8TB capacity and above HDD, the 36W power adapter should be replaced with a 48W power adapter.

On the other hand, on the My Cloud EX2 Ultra manual (p.117) it’s said that:

Power supply:
36W for 4TB, 8TB, 12TB capacity
48W for 0TB, 16TB capacity and above

  1. How do I know what power adapter I got with the device?
  2. I DO have two 8TB disks installed in the NAS what power adapter shall I use?
    By the way, on the “store.wdc.com” that mentioned in the manual, there is no 48W power adapter to buy.

I just put 2 10TB HGST drives in my EX2 Ultra. Copying very large amount of files\data over continuously to basically burn test it.
One thing that did happen was I used the adapter from the single bay MyCloud 3TB drive to power up and format the disks and I did get ‘Power loss detected’ error and the drive rebooted.
This error didn’t return when I used the adapter that came with the Ultra. They look similar and both fit but obviously their is a slight difference that caused my error.

The difference is a My Cloud EX2 Ultra requires a 3A

The My Cloud requires 1.5A

You can use the EX2 power supply to power the My Cloud … but not the other way around.

ie. a using a 1.5A power supply on a device that requires 3A … lets just say things will get very hot and burn and cause damage.

OP should be more concerned with the Amps rather than the Watts which is just the Energy consumption and not the Power/Amperage requirements.


Indeed, yet the manual advises the upgrade to the adapter in Watts not Amps !

in the power supply list


you’ll see that a 48 Watt power adapter is 4A

watt = amp × volt,
So, in order to get a 48w from power supply at 12V, you need it to have a current of 4A…
Elementary my dear Watson.

the EX2 ultra comes with the 4A power brick. the correct adapter has a separable power cord.
if the power adapter has the prongs protruding from the adapter body itself, it is likely less than 4A.

I’ve used the 36watt (3amp) PS on my MyCloud EX2 with 2x10TB WD Red drives for 3 years without any problems. If your drives are 5400rpm CMR drives, you should be just fine.