I know you should not normally DC charge to more than 80% but under exceptional circumstances is it possible to go to 90% or even 100%?
Sure - you just need to make sure you have your DC charge limit set to what you want, but beyond this there are no restrictions.
You're perhaps misunderstanding the context of "80%". You are free to charge to 100% on DC. If there is time-related billing it may be costlier per kWh, or, if other EVs are waiting in line 80% is where it's polite to stop if practical.
Note also that if DC charging, the public charger will (most of them) stop at 80%, designed that way as most users want to stop at 80%. This is not an instruction from the car, and you can over-ride this...
My charge rate on a 150 kW charger dropped to about 20 kW after 80%. Sure, faster than level 2 but boy is not fun sitting in there and waiting. It literally took 30 minutes to get to 80% starting at 30%, and then it would have taken another 20+ minutes to get to 90%. As others mentioned, you're free to do that if circumstances allow (no others waiting, etc).
If you use Electrify America, now they charge by the kwh delivered. It is now no more expensive to charge to 100 than 80 in those states that don't forbid selling of electricity except by utilities. Those states need to change the law.
I agree, a possible quick fix for that, supply a "waiting" button on the DC charger for those who are actually waiting at the charger location. Signage indicating the price/kWh delivered will double if the wait button is actuated past 80% SOC. If no one is waiting...have at it (patience) as there may be circumstances where 100% is required such as distance to the next charging location. Same could be applied to an "app" but still have to physically use the wait button to activate as someone could make a request before arriving.
I often fast charge over 80%...usually to 85 - 90%.. I charge on free 50kw chargers, so the slow charge speed doesn't affect my cost as the cost is zero!
There are apparently a number of them in Florida. I know of one (just one) near where I am. But in general they are pretty rare.
Same here, but if someone is waiting for the charger, then I will move. I have even gone all the way to 100% on a fast charger when no one was waiting. Although these were 65kw charging stations, which interestingly were faster over 80% than 50kw charging stations were, although both dropped below 50kw over 80%.
On long trips I never charged past 74%, its faster to reach the next charger and charge at faster rate than to wait for that slow charge rage past 74%
The location I charge at has two chargers. So far, only once, someone else was using the other charger..