Is the discrepancy just the inefficiency (i.e. waste heat) of the charging circuitry and/or battery chemistry? I'm not positive on the specifics but I believe

Is the discrepancy just the inefficiency (i.e. waste heat) of the charging circuitry and/or battery chemistry? I'm not positive on the specifics but I believe it has more to do with the combination of supported voltages/amperages offered by different chargers. i.e. a "350 kW capable" charger in practice means it can do 800V charging, which other chargers of lower kW ratings typically can't do, and the EV6 requires 800V to reach its max charge speed but can't actually handle a high enough amperage to get to 350 kW. Like I said though, I might be confused on some of the details there, but I'm fairly positive it's not just waste heat...dissipating 110kW of waste heat would require some pretty insane cooling hardware. Oh, and EVs presumably vary wildly in their "fuel economy" (miles per kilowatt-hour or whatever unit EV folks use), so even a "fair" comparison of charging rate presumably wouldn't paint the entire picture. This is indeed a good point. A more relevant measure of charging speed would be something like "miles per hour at EPA rated efficiency", though even that gets messy since most cars don't charge at a linear speed. And I haven't seen any car manufacturers use this metric other than Tesla, who like to brag about their supercharger stations exceeding 1,000 MPH of charging speed (though only the newest stations can just barely do that, for very short durations, and only on certain car models). "Time from 20%-80% charge" would also be a better metric, due to non-linear charging speed curves, but I haven't seen that one used much either.