You should invest $10 (for ADS1015 12-bit adc) or $18 (for the ADS1115 16-bit ADC ) from adafruit. I just tested my ADS1115 last night. For 5V input , I read 26500 counts. With the built in adc on the arduino , you will read 1023. The resolution is 25 times greater
Which would you rather have 150A divided into 1023 counts or 150A divided into 22,790 counts ?