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Re: Power lead

Posted: Wed Jan 11, 2012 2:02 pm
by jimfowler82
Hi,

Just a quick question and hopefully its not too stupid. It says that the Pi is powered by a micro usb 5v yes, Is that the same as the amazon kindle wire you get? If so that will be very handy.

Thanks in advance jim.

Re: Power lead

Posted: Wed Jan 11, 2012 2:12 pm
by piglet
It's exactly the same - and perfect power too as far as I know.

I was planning to use my Kindle charger.

Re: Power lead

Posted: Wed Jan 11, 2012 2:13 pm
by MG2R
I presume you're talking about this:

http://www.amazon.co.uk/Amazon.....038;sr=8-1

That's indeed a micro-USB cable. All you need to do is plug it into a 5V regulated supply

Re: Power lead

Posted: Wed Jan 11, 2012 2:30 pm
by jaygee
these leads appear to be cheaper without the word "kindle" included eg

http://www.amazon.co.uk/Micro-.....038;sr=1-1

Any usb2 port (eg on a laptop) should be able to supply 500mA which is enough for a model A but a model B may draw a bit more in which case a usb mobile phone charger rated at 5v 1000mA (1 amp) would be better.

I've also looked at some pre-usb phone charger some of which would appear suitable if an appropriate connection adapter were made up.

Re: Power lead

Posted: Wed Jan 11, 2012 2:37 pm
by grumpyoldgit
Err. I think the chap was expecting something with a 13 amp three pin socket (if UK) on the other end of the cable. Requiring a laptop to run a Pi perhaps defeats the "size of a credit card" approach".

Re: Power lead

Posted: Wed Jan 11, 2012 2:59 pm
by abishur
The cables are the same, yes.  That means all you need to do is grab an appropriate PSU.  If you search for a "USB wall charger" you should be able to find a charger that fits your needs and has a plug that fit the electrical outlet of your country of choice   Just make sure you get one with a lot of knowledgeable reviews (to make sure you don't buy a charger that claims more than it can deliver) and one that provides enough mA.  500 mA is more than enough for the model A, and should be enough for the model B as long as you're not using USB peripherals that need a lot of juice, but 800 mA is a better safety margin for the model B.

Of course, alternatively, you could grab the power charger from the R-pi store and know that you're getting enough power and know that the PSU isn't a lemon

Re: Power lead

Posted: Wed Jan 11, 2012 2:59 pm
by jimfowler82
I already have a kindle lead, was looking at it and thought i wonder if that will power my Raspberry when i get it

What do you mean by 5v regulated supply though, will this lead by default be that, if connected to my pc or mains in the uk?

Re: Power lead

Posted: Wed Jan 11, 2012 3:01 pm
by RaTTuS

Re: Power lead

Posted: Wed Jan 11, 2012 4:10 pm
by jaygee
Regulated means that the power source is accurately 5 volts (plus or minus a small tolerance) under all loads within its range. An unregulated supply may be much more than 5 volts unloaded and drop in voltage as load is increased - not much good for the Pi.

The lead has nothing to do with this, it just connects the power source to the Pi.

A USB2 socket supplies 5 volts at up to 500mA so this could be used to power the Pi when it is used in conjunction with (say) an HDMI monitor or tv with a usb socket.

For standalone applications a mains plug type psu as shown above is needed, either with usb socket and a lead like these or built in like the maplin one. Whatever you use you need 5 volts regulated and rated at at least as much current as the Pi of your choice will use.

Re: Power lead

Posted: Wed Jan 11, 2012 4:22 pm
by yehnan
Hello, can I ask a question?

My old mobile phone charger:

Input:   100-240V ~ 50/60Hz  0.2A

Output: 5.0V   550mA

Does it mean that it can be used for Model A but not B?



Thanks.