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Having trouble finding a good power supply for the raspberry pi 2

Former Member

Hi. I just got my raspberry pi 2 a few weeks ago and I'm having trouble finding the best power supply for it. I've tested a few I acquired over the years along with a few other miscellaneous ports.

Below are the various results I've come up with when the USB drive is plugged in. max_usb_current=1 is enabled.

1 - Generic 5V 2A adaptor (Red light blinks on pi, hard drive light stays solid then starts to blink. No sound is heard from drive. Drive is not recognized.)

2 - LG 5.1V 0.7A adaptor (Pi shuts down completely. Drive is not recognized.)

3 - Kyocera 5V 0.8A adaptor (Red light blinks on pi, hard drive lights starts to blink, beeping sound is heard from drive. Drive is not recognized.)

4 - Generic 4.5v-6.5V 0.7A adaptor (No red light on pi, hard drive light stays solid then starts to blink. No sound is heard from drive. Drive is not recognized.)

5 - Plugged into Sanyo TV V/A = ? (No red light on pi, hard drive light blinks momentarily then mounts. Connection to drive is not stable and disconnects after a few minutes or immediately after trying to access it.)

6 - Plugged into computer's USB port V/A = ? (No red light on pi, hard drive light blinks momentarily then mounts. Connection is stable and reliable.)

Yes, I know that last one would work but I thought I'd list it anyway. 4 and 5 seem to be the most interesting to me.

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  • 0

    You are telling the 'pi to allow 0.5A or even 1A towards the downstream USB port with the hard disk attached.

     

    With the pi itself requiring roughly 0.7A,  you should be looking at a power supply able to provide at least 1.2A. So the 0.7 and 0.8A adapters that don't work, are no surprise to me.

     

    USB ports on TVs or computers are sometimes not "fused" or "current limited", like they are on the 'pi. So the port will be able to supply more than what the USB-2 specs require (or maybe even "allow"). On the other hand, IIRC, USB3 ports are able to / required to provide more than the old 500mA....

     

    I have tested a few cheap power supplies. I have one that claims 2A, but is actually capable of 1.2A, so that one should work, even though it provides less than advertised.

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  • 0

    You are telling the 'pi to allow 0.5A or even 1A towards the downstream USB port with the hard disk attached.

     

    With the pi itself requiring roughly 0.7A,  you should be looking at a power supply able to provide at least 1.2A. So the 0.7 and 0.8A adapters that don't work, are no surprise to me.

     

    USB ports on TVs or computers are sometimes not "fused" or "current limited", like they are on the 'pi. So the port will be able to supply more than what the USB-2 specs require (or maybe even "allow"). On the other hand, IIRC, USB3 ports are able to / required to provide more than the old 500mA....

     

    I have tested a few cheap power supplies. I have one that claims 2A, but is actually capable of 1.2A, so that one should work, even though it provides less than advertised.

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