A new study has revealed that the problem of out-of-order DCFC (DC fast-chargers) plugs is not a problem confined to Australia.
In a paper published in April on Elsevier research publication SSRN, researchers looked at 657 EV plugs in the Californian Bay Area – the state is home to almost half the EVs in the US – at 181 publicly accessible chargers.
The study said that more than 97% of fast-charging sites included in the study were operated by just three operators: ChargePoint, Electrify America, and EVgo.
It found that more than a quarter of these units were not functioning, or not usable. While fewer than 5% were not usable simply because their cables were too short, the majority were found to be out of order.
“Causes of 22.7% of EVSEs that were non-functioning were unresponsive or unavailable screens, payment system failures, charge initiation failures, network failures, or broken connectors,” wrote the researchers in the report.
Checking a number of the chargers more than a week later, there was no change in status.
“A random evaluation of 10% of the EVSEs, approximately 8 days after the first evaluation, demonstrated no overall change in functionality,” the authors wrote.
Importantly, they note this is not in line with claims made by the charger operators about uptime: “This level of functionality appears to conflict with the 95 to 98% uptime reported by the EV service providers (EVSPs) who operate the EV charging stations.”
Are Tesla Superchargers equally unreliable?
The report did not include Tesla Superchargers, because the study was limited to EV fast-chargers that can be used by all EVs.
While Tesla is trialling opening some parts of its Europe Supercharger network – which in countries outside the US use a universal CCS2 plug – Superchargers in the US use a proprietary plug.
The authors did, however, cite another survey in which just 4% Tesla owners said they’d encountered problems with Tesla’s network.
“In (the) survey of 5500 EV owners, 25% of those who use public DCFCs reported a major difficulty with chargers being nonfunctional or broken (Plug In America, 2022). In the same survey, only 4% of Tesla owners reported a major difficulty with the Tesla closed DCFC system,” the authors wrote.
How can the problem of out-of-order or unusable EV chargers be addressed?
The study said that the most critical design flaw was cable length. According to the study, “7.1% of the Electrify America cables were too short to reach the Chevy Bolt charger inlet, a problem that may be experienced by other EVs with the power inlet on the side of the vehicle.”
This is an easy fix: implement “an industry standard on minimal cord length based on the kiosk location relative to the parking space,” the report says.
However, it adds that the issue of breakdowns “indicates a poor quality of electrical design, components, or software plus the need for EVSPs to improve their identification of the EVSE functional status to trigger timely service.”
It recommends that compliance measures be put in place for EV charging stations, either as “part of a court settlement or paid for with public funds.”
Compliance measures should include “clear definitions of reliability, uptime, downtime, and excluded time” and “consider reliability metrics from other industries (e.g., data centers, cloud service providers, etc.), such as mean time to recovery or mean time between failures.”
Third-party assessments of DCFC chargers using standardised tests at regular intervals is also recommended.
Extracted in full from: Broken EV fast-chargers not just a problem in Australia, study shows (thedriven.io)