USB / Thunderbolt powered external HDD - Is This Normal

[Knuckleheadz]

Hi there,

I have a late 2013 rMBP 13" with 1TB SSD.

I also have a thunderbolt powered external 500GB SSD (Samsung EVO) and an external 1TB USB 3.0 powered HDD (2.5")

I can only have one of them connected at one time and visable in Finder.

Opening Disk Utilities only shows the connected HDD and under SystemInfo I can only see the connected device.

As I final test if I connect my mains powered Lacie 2TB 3.5" drive alongside the SSD it appears or 1TB HDD it appears... and I can plug in two different 2.5" HDD in to the two USB ports and they appear OK.

Could it be the 512GB SSD that is drawing too much power?? Is this a known issues?

Thanks
Jon

 

[rex450se]

When you say "powered" do you mean by the computer or by an outside outlet? Also is the MBP itself plugged in? I have had numerous drives hooked up at one time to my rMBP without any problems seeing them. I think at the most I had 2 USB 3 and 1 TB drive all attached. The 2 USB 3 drives are powered through an outlet though. It may not have enough power, but I'm not sure. hopefully someone has a little more knowledge on this.

 

[Knuckleheadz]

Hey rex450se

Yes I mean powered by the rMBP... none of the external HDD' are powered by their own PSU.

Yes the laptop is plugged in to the mains.

It's definitely the 512GB SSD external drive that is giving me problems as I just tried plugging in two separate USB 3.0 2.5" HDD external drives (self powered) and they both mounted OK.

Just been reading around and there does seem to be some discussion about self-powered SSD's of over 256GB being a problem... but I only see a problem when I go to plug the second USB drive in... as if the SSD has used all the power (and therefore the second HDD doesn't mount) or the other way round and there isn't enough power to mount the SSD.