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Power supply for Raspberry Pi

Posted: Sun Feb 03, 2013 2:12 pm
by mconnolly
Hey all,

I have a Raspberry Pi Model B that seems to be particularly power hungry. It is revision 000F.

I have an HP Touchpad charger and a USB cable that came with my Galaxy Nexus, but the voltage is just not high enough on the Raspberry Pi. According to my digital multimedia, the voltage is around 4.85, and after a couple minutes (even of inactivity), my Ethernet and USB ports go unresponsive (which is typical I hear of an insufficient power situation).

From what I understand, the HP Touchpad charger is on the high end of what is available, so I'm concerned when it appears to not be delivering enough power.

The other option is that too much voltage is lost in the USB cable. I tried a couple others that seemed high quality, but the same voltage (or lower) is registered on the board.

Anyone have any tips for me?

Thanks!

Re: Power supply for Raspberry Pi

Posted: Sun Feb 03, 2013 10:49 pm
by zardoz66
Don't just blame the RPI, it might be a bad power supply. or you your adding something that is to power hungry on the USB. make sure to consider all parts of the system.

Re: Power supply for Raspberry Pi

Posted: Sun Feb 03, 2013 10:52 pm
by Jim JKla
Or you may have a Flaky Pi there is just that posibility. ;)

Re: Power supply for Raspberry Pi

Posted: Sun Feb 03, 2013 11:37 pm
by mahjongg
Pi's are normally quite insensitive to power voltages, its the USB devices that normally are the problem!

Re: Power supply for Raspberry Pi

Posted: Mon Feb 04, 2013 7:16 am
by Jim JKla
Just to be clear I was suggesting RPi as possible cause not effect. ;)

For this RPi only

Re: Power supply for Raspberry Pi

Posted: Tue Feb 05, 2013 3:31 am
by mconnolly
Hey all thanks for the replies.

I have no USB devices plugged in since I primarily just want it to be a headless server. Just Ethernet.

I tried an iPad charger now and got the same result. It is possible that none of my USB cables are good enough but that is a little unlikely I think.

The voltage hovers at around 4.85 but then the Ethernet cuts out. I am assuming due to low power.

Re: Power supply for Raspberry Pi

Posted: Tue Feb 05, 2013 6:38 am
by pluggy
It should be OK at 4.85 volts, all my 3 are good in the long term with less than that. The one sat on my desk headless has an uptime of approaching 2 days at 4.73 volts, its never dropped out, Its stopped because I shut it down or inadvertently deprived it of power. The HDMI misbehaves at such low voltage however.

I'd say you have a flakey and I'd be prepared to wager its a Chinese rather than a Welsh one.

Re: Power supply for Raspberry Pi

Posted: Tue Feb 05, 2013 12:16 pm
by mconnolly
Well that sucks. I guess I have a unit that won't work for me then.

Once the Ethernet goes out out stays out.