I've been wondering, how will Tesla (and other manufacturers) transition to higher voltage DC fast charging? I can only see two options: 1. Change the battery, motor and other car systems to 800V or higher. Cons: You lose the ability to DC fast charge at all existing supercharger and Chademo installations that are only designed for up to 400-500V charging. All the chargers must be upgraded. Pros: Car internal wiring is easier. 2. Keep the battery and motor systems at 400V. Use a DPDT contactor to break the pack in half and put it in series for DC fast charging at 800V, parallel for normal operation (400V). Pros: You get backwards compatibility with all existing DC faster chargers and the ability to charge even faster at new high voltage stations. Cons: added complexity on the car.