Discount UK 5V 1000mA USB chargers - 99p


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by hippy » Sun Apr 22, 2012 2:28 pm
High street store Discount UK are selling an "iPhone / iPod Mains USB Adapter" rated at "5V 1000mA +/- 5%", part number H-28352 for 99p. Single USB A socket outlet.

Not sure on quality or safety – made in China, and the CE marking doesn't conform to requirements; wrong shape – so beware.

If it is safe and reliable, it may be useful in itself, and the case comes apart easily ( two crosshead screws under the sticky label ) to reveal a circuit board that could be removed and wired up within a suitable enclosure to give a 100V-240V to 5V PSU.

That would be a project for people who know what they are doing, done entirely at their own risk. If you aren't qualified – don't even attempt it.
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by Montala » Sun Apr 22, 2012 5:19 pm
Is it really worth the effort, not to mention the possible risks, when you can but a genuine Nokia branded one from Amazon with a 1200 mA output for less than £3.50
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by mc349 » Sun Apr 22, 2012 9:11 pm
Montala said:


Is it really worth the effort, not to mention the possible risks, when you can but a genuine Nokia branded one from Amazon with a 1200 mA output for less than £3.50


Thanks for the heads up.  I've just ordered one of those. "Nokia AC-10X"  it was 1p cheaper than you said.   I'll review it when I receive it.
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by mc349 » Tue Apr 24, 2012 8:56 pm
Well it's arrived.  £3.49 for a AC-10X Nokia charger on Amazon UK,  ordered it Sunday arrived on Tuesday  so no complaints there.

From the outside it does seem to be a genuine Nokia product,  nice molded case with a Nokia logo.  All the correct CE approved markings (not a China Export logo!), double insulated etc.  It could be a fake, but one that they've taken reasonable care over.  It also comes with a Velcro cable tie for the charging cable which sports the Energy Star logo.  The charger is held closed with security "trigram?" screws, not glued or clipped shut like cheaper models.

The charger does say it's rated 5V 1200mA on the casing.    I've tested it charging my Kindle (approx 800mA) and HTC Desire phone (1000mA)  and it's doing fine with these devices.  Only gets very slightly warm to the touch whilst on which is a good sign.  Is completely silent when charging unlike the genuine HTC charger that came with my phone which sometimes emits a very high pitched tone due to the switching supply.

I have a mains plug in current monitor and at idle (plugged into the mains but not connected to anything)  it registered 0.0watts being drawn so that's good. Charging the phone it says 5.9W  so at 5V *1amp that's 5Watts so 1 Watt lost in the conversion to DC isn't bad either.  So it should be cheap to run.

Unfortunately it has a captive cable with a micro USB plug on the end, so I can't get my multimeter probes into the connector to measure the output voltage.  So I'll have to wait till I get my PI and measure on the test points before I can determine what that is.  (I don't fancy cutting into the cable since it can't be replaced easily).  Hopefully it won't be too far out of spec.

But all in all it's looking very good so far...
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by jbeale » Wed Apr 25, 2012 5:10 am
In case of interest, I tested four different "1 amp" rated USB chargers that I had handy. These are the kind that just provide a USB jack, and you connect your own cord. The efficiency ranged from 67 to 72% (DC power out / AC power in) at full load. I measured AC power in using a "Watts Up Pro", not sure how accurate it is. DC power out measured with Fluke 179 multimeter. Efficiency is usually lower at low loads, due to some fixed overhead of the supply circuit.  Here is what they look like:










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by jbeale » Wed Apr 25, 2012 4:32 pm
Regarding my efficiency measurements above: don't read too much into them. I just compared two different "Watts Up? Pro" devices, and the readings differ by about 3 W which at these levels is nearly a 50% error.

The Watts Up Pro spec from their web page is +/-1.5% + 3 counts. Reading is to 0.1 W, so 3 counts is 0.3 watts. One of my devices is way out of spec.
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by mc349 » Mon May 14, 2012 7:23 am
mc349 wrote:Well it's arrived.  £3.49 for a AC-10X Nokia charger on Amazon UK,  ordered it Sunday arrived on Tuesday  so no complaints there.

Just wanted to feedback that this unit seems to work perfectly with the PI, no crashes / fires so far!

I'm running an old Labtec wireless mouse / keyboard + PS2 adapter from a single USB port with no trouble.
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by xtramural » Mon May 14, 2012 8:36 am
mc349 wrote:
mc349 wrote:Well it's arrived.  £3.49 for a AC-10X Nokia charger on Amazon UK,  ordered it Sunday arrived on Tuesday  so no complaints there.

Just wanted to feedback that this unit seems to work perfectly with the PI, no crashes / fires so far!
.

That's reassuring to know since I bought one of these prior to the delivery of my Pi which arrived last Saturday. Sadly, there seems to be a fault with my Pi since it always hangs a short time after booting. I have tried all the usual remedies - all combinations of 3 different PSUs, 3 different sets of keyboards/mice, 3 different SD cards, a powered hub, only Ethernet plugged in and accessed by ssh. It's beginning to look like a temperature-related fault - the opposite of the won't boot/work from cold reported by others. Alas, I don't know of anyone else with a Pi so I can't test my setup(s) with another unit just yet. Farnell have been informed but I'll have to wait for the next batch to be delivered by them to get a replacement sent out.
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by dom » Mon May 14, 2012 8:41 am
@xtramural
Have you tried updating the kernel?
Hexxeh's updater tool is easiest way.
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by xtramural » Mon May 14, 2012 8:45 am
dom wrote:@xtramural
Have you tried updating the kernel?
Hexxeh's updater tool is easiest way.

Yes, the latest attempts to get the Pi working used the latest kernel from github.
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