Toyota are developing a new battery system with 30 minute charging: production 2022.
tinyurl.com/y9fz9zwq
All fine and well, but e.g. a Nissan Leaf uses 0.34kWh per mile. So a car with 200 mile range would need c 70kWh for full range from empty. At 100% chargng efficiency charging in half an hour would require a 140kW supply. At 240V that is a supply current of c. 580A.
A typical home might have 100A supply fuse.
I suspect fast chargers use higher voltages and lower currents, but as the supply coming into the house is 240V then transforming the supply to feed the car won't help.
So home charging will probably be at no more than 30A or 40A. At 40A, using Nissan Leaf efficiency, a 200 mile charge would take 7 hours - presently just right for Economy 7.
A separate network of high voltage charging in residential areas would presumably need its own substations and metering. And Economy 7 would be on its head, with millions of vehicles charging overnight the electricity might be cheaper during the day.
Using Nissan Leaf effciiency, 10 million average cars doing 32 miles per day (12,000 per year) would need a total of 111GWh of electricty per day(night).
Even in a world of very fast charging, most vehicles would need to be charged mostly at lower rates to make infrastructure and peak generating requirements realistic.Super fast charging would be useful for en route recharges on long journeys.
Not intended to be super-logical, just a stream of consciousness. Hope I haven't misplaced any decimal points.
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