The above old battery/new battery problem can be easily circumvented by selling the car for only 300,000 and registering for the Battery Swap system and being charged for only the expense of charging which would be (cost of charging + 10% Profit) probably Rs 10 for every 100 Km!
So people will have to pay just like they pay for the petrol but only at dirt cheap price of Rs 10 for every 100 km and still have the option of charging it at home whenever we are able to.
That I say is the way forward!
The car companies can also use the same format as the Lead Acid Batteries.
Even with different manufacturers... Its not a big deal as only these connectors have to be connected to the car power line... so only this connector has to be similar to the power supply connector inside the Computer connecting different devices like CD-Drive, HDD, Floppy Drive, etc.
So when replacing the battery they just have to slid in the new battery mechanically and then join the connectors manually.