The Nexon EV uses Tata’s Ziptron EV powertrain technology that features a 30.2kWh lithium-ion battery that can be charged from 0-80 per cent in 60 minutes. A home wall box charger takes 8 hours to charge it from 20 to 80 per cent.
For this, we would suggest you walk into the nearest authorized service centre as they will be the better people to assist you. You can click on the following link to see the details of the nearest service centre and selecting your city accordingly - Service centre
The exact information regarding the cost of the battery replacement and other parts of the car can be only availed at the nearest authorized service center. We would suggest you visit the nearest authorized service center for further assistance.
The exact effect of AC of a car's mileage can not be said as apart from AC a lot of electric equipments work that consumes battery. Moreover, Tyre pressure, road/traffic conditions, driving style, etc. We have tested Tata Nexon EV in real-world conditions. You may check out our dedicated article by following the below link in order to get detailed information about its efficiency.- Tata Nexon EV Battery Draining First Drive Review