The change to 2170 batteries will be a game-changer. J Straubel has said the Model 3 Battery could be 30% more energy dense than the Model S. But look at the evolution of the Powerwall 1 to Powerwall 2. 30% may be conservative. The Powerwall 2 has over twice the capacity with only 20% more weight, in a smaller enclosure, and oh yeah, the Powerwall 2 has an inverter built in. Using a conservative comparison, the 2170’s appear to require 19lb per kWh (13.5kWh in 264lb enclosure) compared to 33lb per kWh (6.4kWh in 214lb enclosure) for the old Powerwall using 18650s, or a 57% increase in power density. (Yes I realize these are very rough numbers - just bear with me)
Lets assume the Model 3 is 20% smaller than the Model S. Using a similar battery configuration to the Model S’ 100kWh battery, a Model 3 battery that’s 20% smaller would be 80kWh using 18650s, but could potentially be as large as 125kWh using the (possibly) 57% more energy-dense 2170 batteries. That would be well over 400mile range, perhaps 500. Don’t you think Elon wouldn’t want to wow the world with a 500 mile 125kWh everyman’s sedan? That would be awesome.
Having said that, I realistically think the max battery size will initially be 100kWh, but 125kWh might actually be do-able.