Hello,
i think you can power an arduino via usb-phone-charger.
Are there any limitation on the current for the arduino?
Can i use a charger with "quick-charge"(2 amps) or only a normal charger(<=1amp)?
SOME PHONE CHARGERS ARE NOT ISOLATED FROM THE MAINS.
If they are very lightweight the chances are that they are not isolated. The better ones are isolated so be careful.
They are double insulated so that you cannot access the connections either in the charger or in the phone.
The voltage between the wires is 5 volts but the voltage to earth can be 240 vac
so before you use it test each wire of the charger to earth using a volt meter set on AC600V, Even so if you use the charger on a different socket then test it again because the socket could be wired incorrectly.
To be safe use a plug in RCCB but ensure the trip current is less than 30mA.
Having said that I have many phone chargers so I think that I will test them all.
There have been cases of people receiving shocks when they have dropped their phone in water whilst on charge, So much for IEEE double insulated standard.
It doesn't matter what rate you use the quick charge will be a very slightly higher voltage than the normal charge but the Arduino will take what it wants.
Dead_Ard (retired Electrical and Electronic Engineer)
In principle, it should work with a USB charger on normal or fast settings . The maximum current you can draw, say with the UNO , is about 450 mA.
Some USB chargers, especially portable "power banks" have an auto shutoff if not enough current is being drawn. There are also tricks to suppress this auto shutoff, if required.
Dead_Ard:
SOME PHONE CHARGERS ARE NOT ISOLATED FROM THE MAINS.
By design or only under fault conditions ?
Since switching power supplies rectify main voltage before stepping it down, that sounds anyway rather nasty.
Oh, I forgot to mention, the smoothing in the charger might not be good especially if you try and take two amps so use a large capacitor 1000uF 10vw on the output of the supply if reqired.
I will do some tests on the chargers that I have to see what regulation and ripple are like.
Dear_Ard
It's the cheaper Japanese/Chinese chargers that are the problem some don't use a chopper circuit but just some sort of voltage dropper and a linear regulator apparently, so don't have a transformer in them. I can't imagime a two amp charger using this method. In any case transformers don't guarantee safety especially under fault conditions.
I have aways found a neon screwdriver (mains tester) to be a good indicator but they can also be faulty so don't rely on them.
Use an RCCB, better to be safe than DEAD.
As I said, I am going to do further tests on the devices that I have (I have a couple of two amp chargers).
This post thread will probably be finished be the time I have done the tests.
Have fun!
Dead_Ard
Since my last post I have tested two chargers, One was a texet 2amp charger. This one had no leakage (showed no mains on the output) and even at 2 amps I could not detect any ripple.
The other an ASUS charger was a 1.36 amp output charger, this also did not show any signs of mains on the output. I couldn't measure the ripple on full load because I didn't have the right size resistor but it still looked good at 1 amp. (measured on an oscilloscope).
I hope this helps but to be safe use a plug in RCCB trip.
Dead_Ard
How do I get rid of that Newbie label?
Wow, that was a lot ofinformation. Thanks.
I want to use an cheap double-charger from the dollarstore for my arduino and ESP8266 and put it in a case, where shouldn´t shock me.
I dont want to use it 24/7.
I cant test the charger, because i dont have a multimeter.
Can there happen anything dangerous?