Arduino nano blows up with 12v used for VIN

I have an arduino nano powered by a 12v battery. I have blown up 2 of these arduinos at random times after working hundreds of times. It is strange. Can someone please tell me what i am doing wrong or how to fix it. Thanks

What is this 12V source? What kind of battery?

Anything else connected? If so what and how?

Schematic diagram (photo/scan of handdrawn one if needed) please.

What are you defining as "blow up"? The only detail you are providing is 12V in, which may have nothing to do with the behavior.

The type of battery I am using is attached. I have connected a remote relay to the arduino to trigger a actuator. The part of the arduino which started smoking is also attached. Can someone please explain what part of the arduino this is as it may help me understand why it ‘blew up’. Thanks


Here is the battery sorry

Battery spec

• Voltage 14.40V~15.00V
• Voltage 13.5V~13.80V "

The part that popped is the voltage regulator (which can be replaced, AMS1117 5.0v of the same package). 15V is absolute max on the regulator, cheaper parts won't handle that range well.

Probably didn't help any that you possibly were drawing far too much current if you don't have the relay powered separately from the Arduino.

Which relay (link please)? How connected (diagram please).

If you connected a relay directly to the Arduino (not using some kind of driver or relay board), you might also be blowing up the pin that the relay is connected to.

This isn't an installation issue. I'll move it to Electronics.

Without a schematic, all your's gonna get is guesses, some of which will be good.

A drawing of how you hooked everything together, and a clear close-up photo of the device, showing all the connections, would be helpful. Does the chip you red-circled get really hot during normal operation?

You blew up the Nano's voltage regulator, due to
a) exceeding its voltage input range (look at the datasheet for Arduino Nano and it will tell you: not greater than 12V) -> ok, you obeyed the 12V, but a 12V battery comes with up to 15V ... (look at the datasheet of your battery)
most likely (or even dominated by) in combination with
b) drawing too much current at the same time and thus exceeding the voltage regulator's capablility to dissipate the heat which is caused by the voltage drop at the regulator multiplied by the current being drawn

To be sure, what exactly happened, pls post a complete and precise schematic of your constellation incl. all devices being wired to the Nano as requested here in previous replies.

After that we can calculate the power loss which the poor regulator on your Nano had to take and died from.

To give you a first idea, what will help your Nanos to survive (given that the overall current consumption won't exceed certain thresholds, which are determined by the Nano)

  • If you could power it with a smaller voltage battery -> a 7V battery would do perfectly
  • If you have to stay with that battery, you will have to lower the voltage input to a range of 7V..10V to be safe, which can be achieved by using a voltage step down converter.

This device will then be connected to the battery, its output (adjusted to a safe 7V) will power your Nano.

But - to be sure that this will work, a full picture of all devices in your configuration is needed to calculate the dimensions of the converter and make sure that there is no other issue in your project.

Use a micro-power 5volt buck converter, and connect the 5volt output to the 5volt pin of the Nano.
Then you don't have to replace the regulator (remove the defective one).
And the battery lasts twice as long.

Clones on ebay.

I have a similar problem. My circuit doesn't work. What did I do wrong?

Seriously, a question this vague cannot be answered. A schematic, or very clear and detailed verbal description, is essential. In addition to the "exceeds input voltage" answer, do you understand what inductive loads are and what they will do to you? In addition to everything else, we need to know the exact way (schematic preferred) you connected up your relay. If you don't have a "snubbing" or "kickback" diode in your circuit, you must, must, absolutely must, include one. If you are using a MOSFET to drive the relay, note that some MOSFETs come with the snubbing diode built in, and you will be safe using that. Using a PNP or NPN bipolar transistor, however, is not adequate. The snubbing diode should be a Schottky diode for several reasons, which include the fast reaction time and the very small (typically around 200mV) forward voltage drop. A regular diode has 700mv forward voltage drop, which will possibly lead to exceeding the -500mV limit for the Arduino pins. It is not out of the question for the kickback to exceed 100V, and that will flow from the GND pin to everything else, including the regulator. Hence, tons of guesswork on our part.

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

Thanks.. Tom... :slight_smile:

It is not likely the voltage that is killing them it is likely
the power.
The regulator on the board has almost no heat sink other
than the board.
To regulate from 9v to 5v compared to 12v to 5v is requires 3 times the power
dissipation. A few LEDs or other loads on the regulated output
and the 12v additional watts in the regulator it most likely doing them in.

12volt to 5volt is a 7volt drop.
Wise to keep power dissipation under 0.5watt for the regulator on a Nano (very little heatsink).
That is a current draw of 0.5watt / 7volt = ~70mA.
The Nano draws about 30mA, so you only have 40mA (max) left.
Not enough to power a ~80mA relay board.

See post#11.