Well that's obviously a good thing as the more we know about our vehicles the better.People seem to get all hung up on this. ---- Yes we do.
The hypothesis I'm putting out there is that Tesla controls the taper (and they do change the taper from charge to charge) in order to maintain an average charge rate of C consistent with the overall goals of going easy on the battery as full is approched, when it cold etc. If that is indeed the case then the time required to charge x% should be 0.6*x i.e. a 50% charge should take 30 minutes. Indeed that has proven to be the case for me though I don't do a lot of supercharging and would, of course, like to have more data. Over all the charges I've done, mostly in warm to warmish weather, the rmse using the 1 C rule of thumb is 4.2 minutes. That's definitely good enough to make this ROT useful. If I need to take on 60% charge its going to take me 36 ± 4.2 minutes. The "my charger is bigger than yours" stuff is marketing hype but as long as the power capability of the charger us numerically bigger than the capacity of the battery it appears, from my admitedly more limited than I'd like data, that it takes 0.6 min, for each % SoC increase,The V3 Tesla 250kW statements are just PR and do not reflect overall average speed/time.
I find that it a good idea to read the post that you are responding to before replying.Not all vehicles take 30 minutes to reach 80% SOC. The soon to be released KIA and its twin Hyundia EV are advertising closer to 15 minutes with their 800V battery packs.
Thus with the KIA the rule of thumb may be 0.3 minutes per percent but of course there is no guarantee that the KIA will exhibit the same total time vs delta SoC relationship that the Tesla does. The charging voltage has nothing to do with this. It's the rate at which the OEM wishes to charge his battery.If it turns out that the Rivians charge faster or slower the community will discover this pretty quickly and we can change this rule of thumb to whatever pertains.