# How to select shunt resistor value of the below circuit? We can use Ohm's law but I am still a bit confused

I am very new to hardware development. I am learning all the basics to design a battery management system for electric vehicles in the future.

I would like to know how to select a shunt resistor for my circuit. I have searched in google and got many results. Mainly using Ohm's law but still I am bit confused of choosing a value for shunt resistor for my circuit.

The battery pack I am using is 10s 36v 2.5 ampere hour = 2.5 amperes for one hour.

As per the battery datasheet the maximum current the load can withdraw (discharge) is 2C, so 5 amperesmps for half an hour.

I learned the concept of shunt resistor the value should be small so that it will not affect the load.

I would like to measure the current flowing from the battery to the load so that if it reaches the threshold (5A) I can cut-off the discharge flow. For that I am using a shunt resistor.

I learned the concept of shunt resistor the value should be small so that it will not affect the load, but I am confused how to select the resistor value for above specifications of my circuit.