High speed charging is where everyone that hasn't driven a modern EV on trips (or at least a Tesla) seems to have an opinion. I'll address all the unfounded worries in the FM section of this website. Basically, High speed charging for Teslas involve stopping at either a V2 (150 kw) or a V3 (250 kw) charging station. Most stations have 8-16 chargers, some much more. These are DC chargers that put high voltage, high current charge into your car at up to 520 to 1050 miles of range per hour. Your car actually knows when it is getting close to one on a trip and will start preconditioning the batteries before you get there to ensure they are at the right temperature which gives the fastest and safest charge that the batteries can handle. Ideally, you get to a charger with say 10% charge and charge up enough to safely get to a charger further along your route with at least 10% or so charge...typically that means the car only needs to fill up to 75-85% charge. As a result, you will rarely see longer than a 15 minute charge in a Model 3 at a V3 charger and a 25 minute charge at a V2 charger. A caveat to the V2 charger is you will get dinged a bit on charging time if you are sharing a circuit with another Tesla...you can determine this by noting the 1A 1B 2A 2B, etc numbers on each 'pump' and just make sure you don't have same number prefix as someone else. This sharing is not an issue with V3 chargers. Also, I've never had to wait for a charger in three years and only once had to share a charger with someone else parked next to me (pretty sparse usage in Midwest and East regions so far.) Recent software updates allow the car to recognize when your destination suoercharger is getting busy and might require you to wait for a stall and it can now switch your destination to a less busy station. It did that once for me but I overrode it to see if it was right...as i was pulling up a car was just leaving a stall with all the others occupied so I got right in so, yes, the car was right. By the time i was back with a Wawa sandwich there were only 4 cars charging. The next release of software will also look at which cars are on the way to the suoercharger and consider that timing as well.
Another item to remember is that when you tell the car where you want to go it will route the fastest route for you and then add in all the charger stops you will need to make. No searching for a charger as you are driving or planning a trip around chargers as they cover all necessary interstates in the US. As you drive, the car will keep track of your arrival percentage and warn you to slow down if you do something that eats up too much power (like speeding :) ) and it will even switch charger destinations if you keep ignoring its warning. It is pretty hard to run out of juice in most modern EVs as they also track in real time how many slots are open to charge at in supercharger stations and even which slots are down for maintenance (saw one in Iowa recently...not much inside a Supercharger, btw...basically cables power bus, and lights). Tesla recently reported that their Superchargers have a uptime percentage of 99.96%...pretty decent compared to other fast chargers...have to wonder if that is because Teslas are designed without any screen, card reader, keypad and are weatherproof (no need for shade or protection from rain or snow).
Charging Profile (rate of charge)
One thing to keep in mind is that different EVs have unique charging curves that are design to ensure the batteries don't charge too fast and overheat or stress out the battery, shortening its life. By giving early adopters free supercharging for life as well as unlimited mile warranty for battery replacement, they had first year delivery models getting 100,000+ miles per year added to their cars. They tweaked battery chemistries as well as improved cooling and preconditioning profiles as well as adjusting the charging profiles. Here are some typical profiles:
Here is an interesting point in time map that shows how full stations are at a point in time. This is from the video referenced above.