A capacity model developed over a hundred years ago for capacity of telephone trunks by Agner Krarup Erlang called the Erlang-B model should apply to Tesla Superchargers. See Erlang (unit) - Wikipedia, the free encyclopedia for background.
The biggest error of the Erlang-B model is that it assumes that unserved calls (cars) just go away. However if the blocking rate (the chance of getting a busy signal, or seeing all stalls full) is small, then this is a small error. I did this table using a 2% blocking rate; you have a 2% chance of arriving at the Supercharger and all stalls are full, using the calculator at Erlang B Calculator. Here are the results:
Its interesting to see that the capacity grows faster than the number of stalls, especially at the beginning. Note the capacity going from 1.05 cars being charged to 3.6 when the number of stalls goes from 4 to 8. I hope this means that the long queues at Hawthorne greatly subsided when the number of stalls went from 4 to 8.
Perhaps Farmington, NM will be the first 2-Stall Supercharger... The capacity of a 2-stall setup is pretty small, but maybe that is enough for Farmington.
The biggest error of the Erlang-B model is that it assumes that unserved calls (cars) just go away. However if the blocking rate (the chance of getting a busy signal, or seeing all stalls full) is small, then this is a small error. I did this table using a 2% blocking rate; you have a 2% chance of arriving at the Supercharger and all stalls are full, using the calculator at Erlang B Calculator. Here are the results:
Stalls | Capacity | Efficiency |
2 | 0.20 | 10% |
4 | 1.05 | 26% |
6 | 2.25 | 38% |
8 | 3.60 | 45% |
10 | 5.05 | 51% |
12 | 6.60 | 55% |
Its interesting to see that the capacity grows faster than the number of stalls, especially at the beginning. Note the capacity going from 1.05 cars being charged to 3.6 when the number of stalls goes from 4 to 8. I hope this means that the long queues at Hawthorne greatly subsided when the number of stalls went from 4 to 8.
Perhaps Farmington, NM will be the first 2-Stall Supercharger... The capacity of a 2-stall setup is pretty small, but maybe that is enough for Farmington.