USB3 won't power 2,5" external HDD
Hey guys,
after some wrong items delivered I finally received my USB tester, so I ran a few measurements. For a comparison I measured the USB2 und USB3 port of a cheap netbook with Intel chipset (Trekstor Surfbook E11B) and a all in one PC with AMD chipset (Asus EeeTop E2400A). I used this setup (Pinebook -> Adapter USB-C to USB-A -> USB tester -> adjustable load):
![[Image: cc4f0d-1578524056.jpg]](https://www.bilder-upload.eu/upload/cc4f0d-1578524056.jpg)
I don't know the accuracy of the USB tester so the absolute values should be taken with a grain of salt, but at least the comparison between the three computers should give an idea about the situation.
Here are the results:
![[Image: 9ab72c-1578521734.png]](https://www.bilder-upload.eu/upload/9ab72c-1578521734.png)
(Small brain fart: the surfbook is actually made by Trekstor, not Medion...)
Observations:
The Surfbook and EeeTop USB2 ports allow currents of 1,5A, I did not try to go higher.
The Surfbook USB3 port shuts off* as soon as the current exceeds 1,47A
The Pinebook Pro USB2 port shuts off* when exceeding 0,63A
The Pinebook Pro USB3 port voltage drops sharply when going from 0.99A to 1.0A. Spot on ;-)
The Pinebook Pro USB-C port voltage drops sharply when goint from 1.17A to 1.18A.
The Pinebook Pro USB-C port voltage is overall lower than on all other ports measured, however this might be due to a resistance caused by the USB-C -> USB-A adapter.
*shut off = voltage drops that much that the USB tester does not work anymore
Since even overloading the Pinebook Pro USB ports did not create smoke I became brave and hooked the USB2 und USB3 ports together with a Y-cable and started measuring. All went well up to about 1.16A, but then the Pinebook started making strange noises so I stopped that experiment.
I did not try to measure USB3 and USB-C or USB2 and USB-C hooked together.
However I connected the external hard drives with the Y cable to USB-C and USB3, and both drives spin up, get mounted and work fine without the Pinebook making funny noises. So I can use this combination with my drives. I did not try to power my drives with USB2 and USB3 or USB2 and USB-C hooked together.
![[Image: f4e028-1578525783.jpg]](https://www.bilder-upload.eu/upload/f4e028-1578525783.jpg)
It is a bit difficult to measure hard drive spin up current because the USB tester measurement value display updates slowly und toggles between current and voltage measurement on its own, but as far as I can tell the current during spin up is 0,55A to 0,6A, and when mounted about 0,75A. Yes, when the drives idle after having spun up and being mounted, the current is higher than during spin up, or that's at least what the USB tester displays. It fits to the behaviour when connected to the Pinebook Pro USB-C or USB3 without the Y-cable; they do spin up but won't mount, they just click.
Seagate specifies 1.2A power up current for the hard drive type, which is in fact too much for the Pinebook Pro USB ports according to my measurements.
My guess: The initial movement of the HDD heads draws too much current so the voltage drops too much and they immediately park again. Then the hard drive tries again, thus the constant clicking (once a second or so). The current peak created will not be visible on the USB tester because it updates too slowly.
Final conclusions:
My other hardware seems to be a bit more generous compared to the Pinebook Pro when it comes to current supplied by the USB ports, so that even USB2 ports power my external hard drives just fine.
If I combine the USB3 and USB-C port of my Pinebook Pro with a Y cable, I can power my external hard drives. However this is out the USB specification (?) and therefore risky. Seems to work fine in my case however.
Best regards!
Björn
PS: Here are the pictures and the file with the raw measurement values if anyone is interested:
Dropbox
after some wrong items delivered I finally received my USB tester, so I ran a few measurements. For a comparison I measured the USB2 und USB3 port of a cheap netbook with Intel chipset (Trekstor Surfbook E11B) and a all in one PC with AMD chipset (Asus EeeTop E2400A). I used this setup (Pinebook -> Adapter USB-C to USB-A -> USB tester -> adjustable load):
I don't know the accuracy of the USB tester so the absolute values should be taken with a grain of salt, but at least the comparison between the three computers should give an idea about the situation.
Here are the results:
(Small brain fart: the surfbook is actually made by Trekstor, not Medion...)
Observations:
The Surfbook and EeeTop USB2 ports allow currents of 1,5A, I did not try to go higher.
The Surfbook USB3 port shuts off* as soon as the current exceeds 1,47A
The Pinebook Pro USB2 port shuts off* when exceeding 0,63A
The Pinebook Pro USB3 port voltage drops sharply when going from 0.99A to 1.0A. Spot on ;-)
The Pinebook Pro USB-C port voltage drops sharply when goint from 1.17A to 1.18A.
The Pinebook Pro USB-C port voltage is overall lower than on all other ports measured, however this might be due to a resistance caused by the USB-C -> USB-A adapter.
*shut off = voltage drops that much that the USB tester does not work anymore
Since even overloading the Pinebook Pro USB ports did not create smoke I became brave and hooked the USB2 und USB3 ports together with a Y-cable and started measuring. All went well up to about 1.16A, but then the Pinebook started making strange noises so I stopped that experiment.
I did not try to measure USB3 and USB-C or USB2 and USB-C hooked together.
However I connected the external hard drives with the Y cable to USB-C and USB3, and both drives spin up, get mounted and work fine without the Pinebook making funny noises. So I can use this combination with my drives. I did not try to power my drives with USB2 and USB3 or USB2 and USB-C hooked together.
It is a bit difficult to measure hard drive spin up current because the USB tester measurement value display updates slowly und toggles between current and voltage measurement on its own, but as far as I can tell the current during spin up is 0,55A to 0,6A, and when mounted about 0,75A. Yes, when the drives idle after having spun up and being mounted, the current is higher than during spin up, or that's at least what the USB tester displays. It fits to the behaviour when connected to the Pinebook Pro USB-C or USB3 without the Y-cable; they do spin up but won't mount, they just click.
Seagate specifies 1.2A power up current for the hard drive type, which is in fact too much for the Pinebook Pro USB ports according to my measurements.
My guess: The initial movement of the HDD heads draws too much current so the voltage drops too much and they immediately park again. Then the hard drive tries again, thus the constant clicking (once a second or so). The current peak created will not be visible on the USB tester because it updates too slowly.
Final conclusions:
My other hardware seems to be a bit more generous compared to the Pinebook Pro when it comes to current supplied by the USB ports, so that even USB2 ports power my external hard drives just fine.
If I combine the USB3 and USB-C port of my Pinebook Pro with a Y cable, I can power my external hard drives. However this is out the USB specification (?) and therefore risky. Seems to work fine in my case however.
Best regards!
Björn
PS: Here are the pictures and the file with the raw measurement values if anyone is interested:
Dropbox
