Hi Everyone!

I'm using this mini buck convert for my car project. The voltage source from my car is 12~13V, and the output from buck converter is around 9.5V to feed the Arduino 12V pin.



So now am thinking to add a fuse to my dc-dc step down buck converter to protect it from electric shock.

May I know how many amps should I use? I have read some forums, some of them suggest to use 3-5A amp fuse? Is it correct?

Thanks in advance!

Best
Alan

 

I don't think it is necessary to protect yourself from a shock from such a low voltage source.

 

I don't think it is necessary to protect yourself from a shock from such a low voltage source.

Hi Papabravo!

Thanks for the reply! I'm actually a bit worried that when we start the engine, the voltage will go up to 14V, not sure if it will cause voltage spike, and kill the dc-dc converter & arduino?

 

A fuse is probably not fast enough to provide any meaningful protection.
Read the following article on alternator load dump
https://www.newark.com/diodes-inc/z...etes&msclkid=3c9844dfc5f31216ab87242ec924a162

 

Your Arduino-Board probably already has a Buck-Regulator which can handle
substantially more than the 14.5-Volts from your Alternator.

Spike protection is a good idea though.
If You will provide the Data-Sheet for your Arduino-Board
you might get more useful advice about how to protect it.
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A fuse is probably not fast enough to provide any meaningful protection.
Read the following article on alternator load dump
https://www.newark.com/diodes-inc/z...etes&msclkid=3c9844dfc5f31216ab87242ec924a162

Thanks! will have a read!

 

Your Arduino-Board probably already has a Buck-Regulator which can handle
substantially more than the 14.5-Volts from your Alternator.

Spike protection is a good idea though.
If You will provide the Data-Sheet for your Arduino-Board
you might get more useful advice about how to protect it.
.
.
.

Hi LowQCab,

Thanks for the reply!

Here is the spec of my arduino nano board.
https://www.arduino.cc/en/pmwiki.php?n=Main/ArduinoBoardNano#techspecs

The max input voltage is 12V, I believe if the voltage higher than 12v will kill the board immediately? Lets say, If the voltage spike kill the dc-dc converter, it will feed 13 ~ 14v to my arduino board right?

 

So now am thinking to add a fuse to my dc-dc step down buck converter to protect it from electric shock.

You don't need to protect it (or you!) from electric shock, but a fuse is a really good idea to prevent it from starting a fire.

 

You don't need to protect it (or you!) from electric shock, but a fuse is a really good idea to prevent it from starting a fire.

Hi Ian!

Thanks for the reply! In this case, is it ok if I put a 3 or 5 amp fuse at the 12V input wire?

 

"" Power
The Arduino Nano can be powered via the Mini-B USB connection,
6-20V unregulated external power supply (pin 30), or
5V regulated external power supply (pin 27).
The power source is automatically selected to the highest voltage source. ""

So You have about ~5-Volts of unused Input-Voltage-Capacity,
which in a Car is not all that much,
Car Electrical Systems can be nasty.

A Resistor, a Zener-Diode, and a Capacitor, is all You need to keep it safe.
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