I would like to know about low cost IC (around 1.5$ for 500 pieces)which tat can monitor power from a car battery(12 to 48V) and about low cost 12 Bit ADC IC.
Both IC needed with I2C interfaces.
LTC4151 power (current, voltage) monitor. Haven't used it in a design myself. Just came across it on the web the other day.
AD7998 A/D converter. Used it in a number of designs with success. Don't know if you will consider it low cost (Analog Devices tend to be on more expensive side).