Elon Musk confirmed the news, explaining that increasing the peak power output to 250 kW, required thicker wires:
"We had to increase some wire thicknesses in S/X to reduce resistive heating. Technically, won’t be quite 1000 mph charging, as X especially is much bigger than 3."
However, we don't know whether the change in thickness of wires is the only change applied to achieve the 250 kW.
It's not clear also, since when exactly new S/X got the new hardware improvement to charge at 250 kW. There might already be Tesla S/X users who can charge at up to 250 kW.
Finally, despite the peak charging power increasing to 250 kW, we don't know how much it can improve the effective Supercharging rate. It might be noticeable at a low state-of-charge, but without tests, we can't say whether drivers will be able to get back on the road in a few minutes quicker or not.
Tesla Model S Specs
Tesla Model X Specs
New Tesla cars can charge at up to:
- Model 3 (Standard Range Plus from 2019.36.1 update): 170 kW (previously 100 kW)
- Model 3 (Mid Range from 2019.40.1.1 update): 200 kW (previously 120 kW)
- Model 3/Model Y (top of the line Long Range versions): 250 kW
- Model S/Model X (Long Range "Raven"): 250 kW - (previously 200 kW, 225 kW with 2020.24.6 update)
Tesla Superchargers peak output:
- V2: 150 kW (compared to 120 kW originally)
- V3: 250 kW