Silkroad Online Forums

Hey guys,

I've got an LG Nexus 4 with an adapter of 5 V and 1.2 A output.
Because I need a spare one, I went to dealextreme.com and saw one of 5 V and 1.0 A.
I'm not completely sure about what current the output should be.

Charging devices through USB is recommended by some manufacturers of devices, but I looked it up and the specifications of USB 2.0 are 5 V 0.5 A output.
Doesn't this mean the device doesn't get the appropriate current?

What happens if I use an adapter with a low output current?

I hope someone can explain this to me using some laws of electrical engineering.

Thanks in advance!

Now, I feel terrible for not being certain of this as an engineering student, but I believe it'll just charge much slower...
like half speed or something...

Or maybe it won't charge at all. Shouldn't blow anything up though.

edit: does your original adapter use a non-usb standard?

The regular adapter uses an USB cord.

Edit: What about this: http://www.apogeekits.com/power_adapter_selection.htm

ok me derped a little.
Should've thought of this instantly. Don't buy an adapter that has a lower Current supply than your device needs, doing so will overload the adapter itself and blow it up (had that happen 3x the last two weeks >.>). Just keep searching for an adapter that is 5V 1.2A. If that's what they're using that's what you should stick to.

I don't think usb is limited to 5V 0.5A or something (I don't think there's any parts in there to break with an overload...). Rather it's probably just what is the standard output when attaching it to a PC. -NOT SURE

I found this http://en.wikipedia.org/wiki/Universal_Serial_Bus#Power
I'm very eager to know everything about it, please don't feel offended if this link proves something you've said isn't true.
Can you maybe have a chat with some other students or one of your professors about this subject?
You would really make me happy

V, has to be the same
A, should be equal or higher; if lower -> probably won't even charge your device

USB 2.0:
5 V, 500mA. It does charge my device.

not at all.
I already said in the first comment I wasn't sure.

This engineering course I'm following is relatively new so they're still figuring out how to do everything properly. One major problem has been the complete lack of electrical theory. They basically skipped ALL the basics of how electricity acts and what is required for basic device functionality and jumped straight into shit like Op-Amps and Filters >_>.

I should've gone after it myself, but cba. I haven't been in charge of doing hardware a whole lot, so I haven't need it yet :/
Closest thing to it has been making a PCB for a relay. I'm ussually doing the software side of our projects. I'll try to get a Hardware task next year, or it'll cause me a lot of trouble eventually... (or at least this whole study would've been for naught >_>)

All I know is that my phone takes twice as long, if not more, to charge if I connect it via usb than when I use the power outlet..

Sounds like you're doing interesting stuff! Have fun and I hope you might eventually get me an answer =]



Ok, that's what I begin to understand now. It does make sense, but does it bring risks to use only 500mA current to charge, like overheating components in your supplying USB port?

If the makers recommend it, it shouldn't cause issues... As long as it's not a weird knock-off product.
I'm guessing it's what they called a regulated DC adapter in that first link.
It would kind of explain why it doesn't blow up when the device tries to suck out more current than available and XMoshe's comment also kinda confirms that the lower current output limits the charging speed without blowing it up.

edit:
I did a quick search on google. Judging by the lack of threads that actually cover the subject properly, I'm going to guess the device wasn't intended for USB charging. It is probably not a great idea to try it out, but feel free to look for more information.

If I understand that text correctly even a regulated adapter should have issues with a device that drains more current than available.

OFT:

what do you think of the nexus 4... Im considering to buy either that or the HTC One or S4 however those devices are like... £200 more and I dont know if I can make a good argument for the devices being £200 more, they dont appear to be £200 worth more anyway

I own as well and I couldn't be happier with it, it doesn't lack anything for me.

Put twisted colors with no background on that bad boy and be prepared to be the coolest phone owner in your group.

HTC One and Samsung Galaxy S4 are definitely better phones, because they are next-gen.

One of the main advantages of the LG Nexus 4 is that it comes with stock Android.
No stupid HTC Sense or Samsung TouchWiz. And of course it's priced more reasonable.

Still, if anyone has a fundamental, theoretical approach to the charging problem, I would be glad to hear it.

Those phones got shit on my Nexus 4, the s4 has that gimmick that tracks if you're watching but that's it. Considering other phones for LTE is dumb as well, you don't need 20 mb DL speeds off WiFi and if you wanted that speed you have the option of running dual carriers.