Arduino UNO Powers Off When Connected?

Hi everyone! I'm a bit confused about connecting my Arduino UNO and its attached Ethernet Shield to a 5V USB car adapter.

The car adapter is a Nyko 85100-H17 (, it's actually a PS Vita charger. I don't know the car adapter's power rating, but the wall charger that came with it (also USB) is rated at 1.5 amps.

Anyway, the problem is the following: I plug the car charger into a DC barrel plug connected to a 12V battery that I charge with solar panels; everything lights up, brilliant. Up until a few weeks ago, as soon as I connected the USB from the adapter to the Arduino, the light on the car adapter would go off and the Arduino wouldn't go on. When I unplugged it, the car adapter would go back to normal. I can power the Arduino normally off of USB from my computer, no problem.

Just a minute ago, I took out all the wires the Arduino had connected and tried it again, and it lit up with another car charger, then the Nyko....all the wires I had were simply to control a 7-segment LED display, so there's no way the Arduino could've been eating 1.5 amps (or could it?)

If anybody could bring a little bit of clarity into what's going on, I'd really appreciate it. Thanks! =)

Sounds like something is drawing too much current.
Maybe the 5V regulator is shot.

Hi, just one 7seg display, yes it sounds like a short had developed somewhere.
Can you post a circuit diagram and a picture of your project so we can see how you have hooked everything up.

Thanks Tom..... :slight_smile:

Well, I don't think I'll wire the display again (it was a mess of wires!), but I had at least these pins wired: A0, A5, 2, 5, 6, 7, 8, 3.

6 out of the 7 segments (didn't use the dot), a buzzer which served as an alarm, and I can't remember what I used the remaining analog pin for. Each pin was wired directly to a 330ohm resistor on a breadboard which then connected to its appropriate LED segment. I can't remember if the buzzer's ground went into the breadboard or into the second ground pin, so that might've been the issue. Over the next few days I'll try reconstructing the circuit and see if I find the problem.

Thanks again for your suggestions :slight_smile:

Hi, sounds like you did not draw a diagram before or as you wired it.
Can I suggest you draw what you are going to wire before or while you wire it, it will help you make sure you have it wired properly and also how the circuit works.

It will also help us to help you.

Tom..... :slight_smile: