Power Cables?

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Hey!
I have a micro USB power cable for my Raspberry Pi I just gave a local store the pleasure of 7.99 for so I could have power for my raspberry pi before holiday tomorrow. Sadly, it doesn't work. It reboots the raspberry pi every 2 seconds. Its made for a HTC phone my mom has which the original adapter works fine with my Pi. Do you think I should swap cables with my mom?
Will it charge åt the same speed?
Thanks!

If it has issues with one thing, it will probably have issues with another. You should return it to the store. Until then, I would just use your mom's cable while she does not need it.

Two pins, D- and D+, are shorted together for micro USB cables intended for use with charging mobile phones.
Looks like that's enough to confuse the Raspberry Pi - you'll need a "real" (non-shorted) micro USB cable.

http://en.wikipedia.org/wiki/Universal_ ... _standards

By power cable do you mean a power adapter? If so it is probably being overloaded by the pi. It is probably overheating and and shutting down every few seconds, causing the reboots.

It is quite likely that it won't overheat when used to charge a phone. I would swap them and start looking for a possible replacement just in case.

Looking at the micro USB charging adapter for my HTC, it provides 5V at 1A and since micro USB phone chargers are supposedly universal now, I guess everyone else's would too - but I have no idea how reliable that 1A figure is and it could just mean "approximately 1A".

According to this: http://www.raspberrypi.org/quick-start-guide the Pi requires "a Micro USB power supply – make sure you use a good quality one, capable of providing at least 700mA at 5V" so if the problem isn't being caused by the shorting of D- and D+ in the cable, it could just be that his power supply is a little under-rated to power it reliably.
This has a little more detail on the supply type: http://www.raspberrypi.org/archives/260


I'm assuming now that "cable" does in fact mean the complete power source, including the USB cable. I thought he just meant the cable alone but now you mention it, it's possibly more than that. Since he has a power supply which does power it reliably, any issue about the cable D-/D+ lines can be resolved by swapping the new cable with the original on the working power supply.

Looks like he's on holiday now so I guess we'll have to wait...

So, using the original power supply which was known to work with one cable - does it now fail when the other cable is used instead?

Problem caused by D- and D+ shorted, I'd say, since the cable you bought was intended for use with charging a mobile and not a "real" micro USB cable.

I can personally recommend the charger supplied with the Samsung Galaxy S II for powering the Raspberry Pi, I have used this with no problem, they're probably not that cheap to get hold of if you don't have a Samsung smartphone but they do the job.

Another thing worth checking just in case is that you're not overloading the USB ports on it, don't forget that on the Raspberry Pi they can't supply the same 500mA per port that a desktop or laptop can.