That's going to be one heck of a charger!
I get about 5 miles per kWh in my Chevy Spark EV. From a conventional 15A circuit, I can draw about 1.4 kW. So, if I drove my car for 80 miles, I would need to replace 16 kWh and, at best, that would take 11 hours. Actually, it takes longer because the charger doesn't put out 1.4 kW. There are some 8 hour chargers that run on 240V so they put out about 2 kW. There are some commercial 30 minute chargers, so 32 kW (that's a really big number).
But my battery would need to be 4 times as big to go 300 miles and that comes out to around 2 hours even with the commercial chargers (at Walgreen's).
Maybe they get better mileage but it's not that good! I just wonder what their charger looks like and, more importantly, how their car will perform with the chargers being installed up and down the state of California.
Once the hype settles, I might be interested. We got the EV because we had solar and could drive for $0.03/mile. Now that we have moved, we don't have solar and the price goes up somewhat.
Battery cars are going nowhere until there is infrastructure in place for rapid recharging but, finally, the 300 mile range seems workable. But it's about the infrastructure. It's fine to stop for 30 minutes every 4 hours and grab a snack while the car charges. It's not fine if I can't recharge overnight on a home charger. If I worked, I would want to drive to work, perhaps get a free charge courtesy of my employer, drive home and get enough of an overnight charge to do the morning commute.