The Tesla Supercharging network is known for its outstanding reliability, which, according to the manufacturer, is near-perfect, with a record-high average uptime in 2023.
According to Tesla's 2023 Impact Report, the average uptime of the Supercharger sites globally amounted to a record 99.97%. This result outpaced the already impressive 99.96% in 2021 and 99.95% in 2022.
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Fast Charging Reliability
DC fast chargers happen to be broken from time to time for a variety of reasons. Because the ability to recharge an EV along the way is essential, high uptime is very important for charging networks.
If we look at the previous years, it will turn out that the network consistently achieves a result close to 100% reliability. However, the key is understanding Tesla's average uptime definition.
Average uptime of Supercharger sites*:
- 2018: 99.94%
- 2019: 99.90%
- 2020: 99.74%
- 2021: 99.96%
- 2022: 99.95%
- 2023: 99.97%
The company explains: "*Uptime of Supercharger sites reflects the average percentage of sites globally that had at least 50% of their daily capacity functional for the year."
In other words, the stat is based on the stations (locations) rather than individual stalls. According to Tesla, a station has perfect reliability as long as at least half of the stalls are online.
Tesla's metric of average uptime is interesting, but as usual, statistics have weaknesses. In this case, the general average concerns stations, not individual stalls.
In an extreme theoretical example, if up to 49.9% of the stalls at each station were dead for the whole year, and the remaining 51.1% would be online for the entire year, then the result would be a perfect 100% uptime, according to Tesla. The same 100%, of course, would be achieved if 100% of the stalls were online for the whole year.
It's great that Tesla Supercharging stations offer at least half of their fast charging capacity for the vast majority of the time. However, it would be great to see the reliability stat for the individual stalls. What was their average online time over 365 days?
The uptime for the stalls would be lower than for the stations, which would reveal the real progress in hardware reliability.
