Suggest laptops which has 20 - 32 hours battery backup within Rs 50000 to 80000?

Can you suggest laptops which has 20 - 32 hours battery backup within Rs 50000 to 75000 cost.
I would like to buy from HP, Lenovo, Asus, Acer and Dell. I would like to buy from Bangalore, India.

There are no such laptops. If you want that much time, you will have to buy around 4 spare batteries, and also an off-line charger would be useful.