Arduino's crashing on voltage above 10 volt


In te last couple of years i have done several Arduino projects involving multiple kinds of Arduino boards (all original). One thing i have noticed is that when i power the Arduino using the Vin port it works fine between 6v and 9v but when i go any higher it tends to crash after a while and reboot, if i go above 12v it will crash immediately over and over again. Most of the time i just keep te supply voltage around 9v even tho the boards are rated for 6-20v. The code i used have varied a lot but this problem keeps occurring, i also used multiple kinds of power supplies but with no result. Does anyone may have any idea why this happens? I included a simple code example which i used and some photos from when it crashed. Also when i don’t upload any code it seems fine.

int relay = 2; //main heater
int Led1 = 12; //On and off Led
int Led2 = 11; // Led for working temp
int Led3 = 10;
int Led4 = 9;
int Led5 = 8;
int zoom = A5;
int b1 = 7;
int b2 = 6;
void setup() {
  // put your setup code here, to run once:
void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(Led1, HIGH);
digitalWrite(Led2, HIGH);
digitalWrite(Led3, HIGH);
digitalWrite(Led4, HIGH);
digitalWrite(Led5, HIGH);
if (digitalRead(b1) == HIGH){digitalWrite(relay, HIGH);}
else {digitalWrite(relay, LOW);}
if (digitalRead(b2) == HIGH){digitalWrite(zoom, HIGH);}
else {digitalWrite(zoom, LOW);}
} (1.52 MB)

Have you taken a look at the voltage input specs for an Arduino and noticed what the highest input voltage should be?

Are you operating a relay directly from an Arduino pin? Look at the current rating of your relay coil and compare that to the current supply rating of the Arduino GPIO.

Thanks for the quick response!

I have had the problem with multiple boards including the uno Rev3, MEGA and nano. All of them are rated for 7-12v recommended and 6-20v limits.

The relay in this example was powered using an external supply but this problem also showed up when not using any relay. I checked if any of the pins had to supply more than the rated 40mA but that wasn’t the case.

kota19911: All of them are rated for 7-12v recommended and 6-20v limits.

Could you send me the link to the 6-20v limit for the Arduino's?

kota19911: The relay in this example was powered using an external supply but this problem also showed up when not using any relay. I checked if any of the pins had to supply more than the rated 40mA but that wasn't the case.

Can you send me the part/model number of the relay you are using? I'd like to have a few relays with coils that can be directly connected to the Arduino GPIO. Can you post some schematics of your relay connections; Not the FritzNuts thingies?


The recommended max power dissipation for the 5V regulator on Uno and Mega is 1 Watt. That means with 12V to Vin the max current out of the 5V regulator is about 142mA (1W / (12V - 5V). Drawing more than that current can overheat the regulator and cause the regulator to shut down. Almost half of that 142mA is used by the Uno or Mega itself. What else is connected to the 5V regulator output?

Thanks for all the responses!

Starting with Idahowalker, the volt limits for input i found in the Arduino store, for instance with the uno Rev3 ( under techspecs it says "input current limit 6-20v" and (correct me if i'm wrong) but i thought this was for the barrel and the Vin connectors right?

The relays i'm using are the G5Q-1A EU 5DC from Omron, schematics will follow.

Spycatcher2k: i already tried 4 different power supplies but non of them changed it unfortunately.

GroundFungus: Are you sure it's only about 142mA? I googled it before and there they said it could handle 200mA for all the I/o pins and 700 mA for the 5v pin at around 7v input. Would clarify why it crashes when i up the voltage tho... Next to relay i also added 6 12mA led's, a 30mA buzzer and 2 DS18b20's and a dht22 humidity sensor.

200mA for all the I/o pins

That is for the processor chip, not the regulator.

700 mA for the 5v pin

That may be the current output of the regulator with adequate heat sinking. There is not much heat sinking on the boards. The 1 Watt recommended is a figure that I have seen in more than 1 place so I tend to go by that figure. See reply #1 of this post.

The DS18B20s (1.5mA max, each) and the DHT22 (2,5mA) draw very little, but the LEDs and buzzer get 72 to 102 mA. Add that to the 50mA that the Uno takes and you are into the area of dissipation that can cause the regulator to overheat (with a 12V to Vin).

Does the regulator get hot?

edit: Also, bear in mind that the 3.3V regulator is fed from the 5V regulator so the current from the 3.3V regulator must be added in.

Why are things going wonky?

@kota19911, You mean this:

Input Voltage (recommended) 7-12V
Input Voltage (limit) 6-20V

I am going to say that if you want to run the Uno at the extremes, good, but expect issues.

Those are voltage ratings not current.

So you are hooking

General Purpose Relay SPST-NO (1 Form A) 24VDC Coil Through Hole

to an Arduino and expecting it to work?

The relay does not match to the Arduino and no amount of raising the input power supply voltage is going to make the 24V relay work from a GPIO pin without some additional electronics.