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Author Topic: A10 + hdd power requirements  (Read 3455 times)

kermit80

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A10 + hdd power requirements
« on: April 27, 2014, 05:07:11 PM »
Hello,

I'm wondering how much power is needed to power the A10 + hdd.
I own a 2.5", 0.85A, USB drive.
Connected to one of the A10's usb ports it doesn't receive power to spin properly.
If I connect the drive to both usb ports, the board shuts down as if the power drain is too much.
I'm using a 10W (5V, 2A) power supply connected to the A10's OTG port.
The hdd works properly connected to my laptop.
Do I need a bigger power supply?

Thank you.

Lurch

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Re: A10 + hdd power requirements
« Reply #1 on: April 27, 2014, 06:00:20 PM »
The USB ports are current limited to 500mA. Commercial products sometimes use a second cable where just ground and +5V are connected, the other pins are not connected.
I kind of suspect that this type of 'power sharing' might not work on the A10.
You could try a powered external USB hub with the power sharing variant - the circuitry may better account for what you are doing.

kermit80

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Re: A10 + hdd power requirements
« Reply #2 on: April 27, 2014, 06:49:54 PM »
Thank you very much. I have very little knowledge about usb.
I guess I'll just get a sata + power cable and try that way. It's just a notebook sata hdd plus an external usb enclosure which I can take off.

Lurch

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Re: A10 + hdd power requirements
« Reply #3 on: April 27, 2014, 11:36:55 PM »
I connected mine (2,5" Toshiba 500GB 5V @ 1.0A) using the Olimex cable, which plugs into the SATA power socket on the A10 LIME and have had no problems at all. The MQ01ABD050 (also sold by Olimex) is also extremely quiet.
If you can get the cable set (SATA-CABLE-SET) from Olimex, it's a good fit.

kermit80

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Re: A10 + hdd power requirements
« Reply #4 on: April 29, 2014, 12:36:39 AM »
I have the sata cable set that came with my cubieboard but the power connector doesn't fit. Thought that was a sort of standard. Too bad but I just ordered the Olimex one from Amazon. I really like the A10-Lime, hope to have it connected to the hdd soon. It's going to serve as a bittorrent sync backup node.

Lurch

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Re: A10 + hdd power requirements
« Reply #5 on: April 29, 2014, 01:11:40 AM »
There's a thread about how to boot from the SATA (well, it needs the SDCard to load a ramdisk, but the rest is from SATA).  With that, the LIME is really quite nice.

flobber

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Re: A10 + hdd power requirements
« Reply #6 on: April 29, 2014, 03:41:30 AM »
This answer should come from Olimex but it seems they are busy...

Each of the three USB-ports on the LIME has its own 500mA
current limiter.  If the board shuts down when two ports
draw 500mA each, the power supply (PSU) is insufficient.
HDDs draw a lot of current when they start their motors and
the PSU may have problem keeping its voltage when there is
a sudden demand.

You could try to first connect the HDD and then turn on the
PSU. If you are lucky, the HDD starts faster than the A10
and the PSU has recovered at the time the A10 starts.

A second work around: add a battery.  It may take over if
the voltage of the PSU breaks in.

Best solution though: get a sane PSU!

Btw, the current limiters on the LIME are tuneable and can
be set to anything between 400mA and 2000mA.  You just have
to change a single resistor.  I.e. change R41 to 6k8 and
port 1 will provide 1A.  No need for an Y-cable any more.
But don't overdo it - the total continuous power consumption
of the LIME should be kept below 3A (limit of D3).

Ciao.

PS: Isn't it nice to have schematics? ;-)

kermit80

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Re: A10 + hdd power requirements
« Reply #7 on: May 06, 2014, 12:10:35 AM »
got the cable set and a 12W psu today. still it's not enough to power up the lime with the sata hdd connected. the same hdd power up just fine on the cubieboard with a 10W psu. pity.

kermit80

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Re: A10 + hdd power requirements
« Reply #8 on: May 21, 2014, 10:24:34 PM »
Update: doubled the watts and the lime is running flawlessly with the sata drive connected. I'm still very happy of my A10! :)