The E-GMP solution is also a clever one. I believe the inverter is limited to about 150 kW sustained (I think it can peak a little higher to the motors). 150 kW isn't bad but it's also a fair ways away from the 230 kW E-GMP will do on 800V.
Presumably it can charge either at 400V or 800V depending on the charger it's plugged into. But I think you're right, Ultium is still a 400V drive architecture versus this being an 800V drive architecture.
TBH, I'm really looking forward to seeing the Tesla tested on 800V CCS chargers via the adapter. It seems like it is at least possible that it might charge faster on those than on the current 400V superchargers.
Of course, that would change if Tesla starts enabling 800V support on V3/V4.
Yeah, I saw that, but tbh, I'm taking it with a grain of salt at this point. We've already seen one screenshot of the charge rate at ~70% and it wasn't great. It was showing ~10 minutes remaining to get to 80% too. That was on a slower charger, but the charge rate was less than 80 KW.
Considering how bad the 4680 Model Y was, I'm not optimistic.
GM's clever solution is to present the battery pack as 2 400V packs. It does pose some very tricky pack balancing requirements though.
Other 800V cars charge quite poorly on 400V stations, usually with a hard cap at much lower than the potential max charge due to inverter limits.