How much electricity units consume while charging electric cars?

sir what is capacity of battery mentioned in manual as kWatts multiply that by rupees/kwatt for amount calculations

Some very basic terminology is important to establish, since I regularly see people talking as if they don't understand what an "ampour" or "ampere" is, especially people used to dealing with roadside illiterate battery-walas or jugaar ustaad electricians.

If you have a motor running at 1,000 watts (W) of power for an hour (h) it will have consumed 1,000 watt-hours (Wh) of energy. This can also be expressed as 1 kilo watt-hours (kWh.)

Similarly, a battery rated at 50kWh can (in theory) produce 50,000W for 1 hour. It can also produce 10,000W for 5 hours, or 5,000W for 10 hours, or 5W for 10,000 hours. There are more factors involved, but this is a simple way to think about it.

If your car has a 100kWh battery, it will consume 100 units of electricity to charge, since the "unit" used by utility companies is 1 kWh. However, this is only if the charging efficiency is 100%.

In reality, you lose energy as electrical energy is transmitted (through conductors as heat) and converted (AC/DC or DC/AC) and you must account for transmission or conversion losses.

Lithium batteries like to charge at a temperature that isn't too cold or too hot, around 21°C, so charging your car in very cold weather means your car will use consume more units of electricity to keep the pack warm as it charges.

Hot weather or fast charging makes some EVs turn on a chiller system to keep the batteries cool, either by using a dedicated compressor (similar to that used for the air conditioner) and heat exchanger to remove heat from the coolant circulating around the batteries, or by turning on the on-board AC compressor and diverting coolant flow to the pack. This, naturally, also uses more energy.

Finally, these numbers vary depending on the car, charger and ambient temperature, but you can expect around 85% efficiency charging with an "overnight" variety AC home charger running at 120V. 240V AC charging can up the efficiency to as high as 95%, and DC fast charging can get you very close to 99% efficiency.

Note that most EVs also don't charge from 0% - 100% all the time. To maintain battery longevity, they are configured to charge only to about 80% or so. You might decide to plug your charger in at 20% and charge to 80% overnight in the cold, or be rapid charging from 5% to 100% with a hot battery right in the middle of a charging stop on a long trip.

TL;DR to get a very rough overestimated value, the capacity of the battery in kWh = number of units of energy used.