zocko
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Power Supply

Wed May 30, 2012 1:08 am

Good Day,

Can anyone point me to a power supply which will work with the Pi for USA power?

Thanks for your help!

- Zocko

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kaidenshi
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Re: Power Supply

Wed May 30, 2012 1:54 am

Pretty much any 5v cellphone adapter with a MicroUSB connector and at least 700mA (0.7A) rating will work. I'm running mine off of a 700mA adapter from an old LG phone that died a couple of years ago. Those things are dirt cheap on Amazon and eBay.

You can also use four AA alkaline cells or five AA rechargeable NiMH cells, again through a MicroUSB connector.

zocko
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Re: Power Supply

Wed May 30, 2012 12:35 pm

Thanks kaidenshi - I think I have a couple of those from old phones too. - Zocko

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kaidenshi
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Re: Power Supply

Fri Jun 01, 2012 5:01 pm

I just wanted to follow up with a suggestion to go for a 1000mA or higher power supply. I've noticed my Pi not always rebooting properly with both USB ports occupied, and I've heard of other people having issues with 700mA power supplies doing the same or randomly rebooting. Those people have fixed the problem by using a supply with a higher rating.

I'm going to try the 1100mA supply from my HTC phone and see if it improves things. If that fixes it, I'll look into a more robust supply, perhaps even one with an inline power switch so I don't stress the microUSB connector too much.

smuggly
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Re: Power Supply

Sat Jun 02, 2012 12:46 pm

I'm Using the one you are talking about HTC Power Supply Works Great!

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kaidenshi
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Re: Power Supply

Sun Jun 10, 2012 8:24 pm

Another follow up, the 1100mA supply from my HTC phone worked wonders, the Pi is stable with both USB ports and the Ethernet port occupied and streaming data.

Now that I'm having to save up money for parts for my weather station project, I've put the Pi back on the 700mA supply and am running it with only power and Ethernet hooked up as a simple web server under Arch Linux. I've been able to ssh in and run updates, serve complex pages with PHP and perform other mundane tasks without power issues. So, if you are planning to run your Pi as a server without a bunch of USB addons, I'd say a 700mA or greater supply would be adequate. Once you start looking into more dynamic roles, I would go for at least 1000mA as suggested before.

srynoname
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Re: Power Supply

Tue Jun 12, 2012 3:52 pm

The power supply from which HTC phone exactly provides 1100 mA? E.g. my Desire power supply only provides 1000 mA, as I want to buy a second one, I'd like to buy the one with 1100 mA. Thanks :-)

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kaidenshi
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Re: Power Supply

Wed Jun 13, 2012 6:11 am

Sorry, mine is an HTC Arrive. (yeah I know, WP7 BOOO!!! I like it though)

From what I've read, the Arrive's charger is the same as on most HTC phones from the last year. You might be able to pick one up for cheap on Amazon or another vendor.

For car use, there are a ton of 2100mA lighter socket to USB adapters out there; the ones marketed for the iPad tend to be cheap and reliable. For those in the U.S. you can try this:

http://www.walmart.com/ip/Bravo-View-2. ... d/16814144

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rurwin
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Re: Power Supply

Wed Jun 13, 2012 6:26 am

There was another thread where a few of us posted the model numbers of our HTC chargers, and oddly enough they were all different. I have no idea why that should be; surely it just costs money to have multiple models of charger, all supplying around 1A at 5V. However the good news is that they all work.

And for what it's worth, mine is a Legend charger, model TC P300.

zog
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Re: Power Supply

Wed Jun 20, 2012 11:54 pm

I have had problems running the pi with a powered hub and using a seperate power supply for the pi rated at 1A. I found the dual power supply configuration was unstable and the pi would restart itself if the powered hub was left on and then turn itself off. I also suspect that two unearthed switched power regulators will fight each other and lead to unstable voltage regulation. My USB ports seemed to switch themselves off and behave in a strange manner.
If you intended to use a powered hub a good solution is to power the pi off the hub using a USB to micro usb power connector. I got a belkin mobile usb 4 port hub with a 2.5 amp power supply at 5v, powered the pi off this using a usb port, and connected its up to the PIs usb output port.
Therefore you only have 1 PSU and powered ports for usage. This configuration seems very stable and I haven't had any keyboard issues since. It also has the advantage that when you turn the PSU off everything get turned off and the pi can't draw power from a usb hub that is still on.
Technically speaking you should use a Y cable to supply the PI from the hub as a usb port can only supply 500 ma. However with the belkin hub this didn't seem to be an issue powering it on and off. I got my powered hub from tesco's. I borrowed my HTC titans usb to micro usb cable.
IMPORTANT NEVER POWER THE RAS PI FROM A COMPUTERS USB PORT USING A USB TO MICRO USB CABLE AS THE PI DRAWS MORE THAN 500 ma. You might damage the host computer!

Th3ArCh0n
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Re: Power Supply

Sat Dec 29, 2012 10:23 pm

Wish i would have read this earlier, that was the first thing i did, power it through my desktop USB

Alan_
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Re: Power Supply

Mon Feb 23, 2015 10:28 pm

Sorry to necro this thread, but I have a valid reason imho.

I found this because I plan to power my Pi 2 using a 5.1V 700mA wall charger, it seems it's gonna work.

However, I don't agree that you can damage your computer by powering the Pi from one of the USB ports. If that was the case, any USB HDD would damage the computer because I've never seen one rated less than 850mA, and it takes even more than that when spinning up. Some are even rated 1500mA.

Also, it seems those official numbers are extremely conservative:
http://raspi.tv/2014/raspberry-pi-a-how ... es-it-need
http://raspi.tv/2014/how-much-less-powe ... ld-model-b
http://megarpi.inf.unibz.it/index.php/h ... onsumption

DirkS
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Re: Power Supply

Mon Feb 23, 2015 10:41 pm

Alan_ wrote:However, I don't agree that you can damage your computer by powering the Pi from one of the USB ports. If that was the case, any USB HDD would damage the computer because I've never seen one rated less than 850mA, and it takes even more than that when spinning up. Some are even rated 1500mA.
Keep in mind that this topic is from the time that you could not power a HDD at all, so your post doesn't really relevant...
The first two pages you link to are about the 'plus' models. These were not even available at the time this topic was written!

Alan_
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Re: Power Supply

Tue Feb 24, 2015 12:37 pm

DirkS wrote:
Alan_ wrote:However, I don't agree that you can damage your computer by powering the Pi from one of the USB ports. If that was the case, any USB HDD would damage the computer because I've never seen one rated less than 850mA, and it takes even more than that when spinning up. Some are even rated 1500mA.
Keep in mind that this topic is from the time that you could not power a HDD at all, so your post doesn't really relevant...
The first two pages you link to are about the 'plus' models. These were not even available at the time this topic was written!
Sorry, I don't understand... are you saying that in 2012 a computer couldn't power a HDD? That doesn't make any sense.

I just posted that because some people may access the page and think it's not a good idea to power the Pi from the USB port of a computer, while in fact it's perfectly fine because there are plenty of USB devices out there that draws way more power than the Pi and they never caused any damage to a computer afaik.

So, you can power the Pi from a computer. It's never late to correct wrong information on the internet imho.

jamesh
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Re: Power Supply

Tue Feb 24, 2015 12:41 pm

The original Pi's didn't have powerful enough USB ports to drive a USB harddisk without its own power supply. This was corrected in the B+ model.

I've powered the Pi2 from a laptop USB port, works most of the time, until you start to do things like run the camera at the same time and the decoder and networking. Started to drop ethernet connection and give the rainbox box warning.
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Please direct all questions to the forum, I do not do support via PM.

Alan_
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Re: Power Supply

Tue Feb 24, 2015 12:45 pm

jamesh wrote:The original Pi's didn't have powerful enough USB ports to drive a USB harddisk without its own power supply. This was corrected in the B+ model.

I've powered the Pi2 from a laptop USB port, works most of the time, until you start to do things like run the camera at the same time and the decoder and networking. Started to drop ethernet connection and give the rainbox box warning.
But I'm not talking about powering HDDs from the Pi, I'm just saying that any computer can power a Seagate USB HDD rated 1500mA, so obviously, any computer will also be able to power the Pi, especially since it hardly draws more than 500mA it seems (links above).

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RaTTuS
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Re: Power Supply

Tue Feb 24, 2015 12:52 pm

I found someone wrong on the internet !... http://xkcd.com/386/

however there are several issues here
1) thread neco

2) you used to be able to power the RPi via the normal USB socket - however because of how it was made the system would not get a full 5V so would be very unstable,
this was changed in future RPi's - so that you could back power the RPI from the USB socket
it has now been changed again so you cannot backpower

3) devices are supposed to ask if they want more than 500mA - many many many devices and hubs don't bother - cheep ones tend to just wire the +5V bus together and let the electrons flow [this is not necessary a bad [or good] thing depending YMMV]

4) Most PC's will provide more than 500mA on their USB bus ... [some will not]

5) having several PSU's all pushing +5V +/- 5% on the same bus is not a good thing

6) you may find that 700mA is not enough to power A RPi2 - YMMV - it may not be 700mA it may have too much Voltage drop etc...

7) other stuff
How To ask Questions :- http://www.catb.org/esr/faqs/smart-questions.html
WARNING - some parts of this post may be erroneous YMMV

1QC43qbL5FySu2Pi51vGqKqxy3UiJgukSX
Covfefe

Alan_
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Re: Power Supply

Tue Feb 24, 2015 12:59 pm

RaTTuS wrote:I found someone wrong on the internet !... http://xkcd.com/386/

however there are several issues here
1) thread neco

2) you used to be able to power the RPi via the normal USB socket - however because of how it was made the system would not get a full 5V so would be very unstable,
this was changed in future RPi's - so that you could back power the RPI from the USB socket
it has now been changed again so you cannot backpower

3) devices are supposed to ask if they want more than 500mA - many many many devices and hubs don't bother - cheep ones tend to just wire the +5V bus together and let the electrons flow [this is not necessary a bad [or good] thing depending YMMV]

4) Most PC's will provide more than 500mA on their USB bus ... [some will not]

5) having several PSU's all pushing +5V +/- 5% on the same bus is not a good thing

6) you may find that 700mA is not enough to power A RPi2 - YMMV - it may not be 700mA it may have too much Voltage drop etc...

7) other stuff
0- This is not "the internet", this is a forum where afaik people are supposed to learn and share information
1- I don't see problem in necroing when you have a valid reason
2- I'm talking about using a USB->MicroUSB Cable.
3- You know what, in real-life, they doesn't.
4- Most is read as ">99.9%" here, because you won't find a PC that can't power a USB HDD, and any USB HDD needs >500mA
5- Have you even read the other posts?
6- It is. Even if you're using a keyboard and mouse and USB flash drive and decent wifi dongle on it. And of course using the ethernet.
7- Your hate and nonsense it not needed here. Thank you for understanding.

texy
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Re: Power Supply

Tue Feb 24, 2015 5:49 pm

OK, I think we have gone far enough. Please play nicely.....
Various male/female 40- and 26-way GPIO header for sale here ( IDEAL FOR YOUR PiZero ):
https://www.raspberrypi.org/forums/viewtopic.php?f=93&t=147682#p971555

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