EV drivers everywhere have had the same experience – you pull up to a charger you found on an app, and you can't get a charge. Maybe the charger is off, the cable is broken, it doesn't accept your payment, or your vehicle doesn't get enough power.
Uptime and reliability of EV chargers is an important topic of conversation right now, and rightfully so. For fleets, the issue is especially critical – if you can't charge up your rideshare vehicle, delivery van, or drayage truck, you can't run your business at all.
In this article, we'll go over one way uptime is measured today, how charger reliability needs are different for fleets, and how a single uptime metric doesn't capture a variety of common error scenarios.
NEVI, a program aimed at expanding charger coverage across all 50 states in the US, includes one of the most prominent examples of measuring charger uptime. Let's look at it as an example:
All of the details can be found in the code of federal regulations here.
The NEVI requirements above are a good starting point, but aren't strict enough for many fleets:
However, unlike public charger operators, fleets can take advantage of the more options to improve reliability:
Beyond this, the very idea of measuring uptime as a single percentage metric has some flaws.
In our experience with charger management for large charging sites, we've found that charger uptime and connectivity is usually not representative of charger health. It's very common that a charger reports that everything is OK, but there's a one-off issue that doesn't allow charging to happen, for example:
These would not show up on a "charger uptime" metric as described above, because the charger is not "down" for any amount of time. It's a single point-in-time failure that significantly disrupts operations, but it's unclear if the charger should be considered "broken".
Since most of the issues that affect fleets can't be captured in a single uptime metric, it's important to always look at several metrics for charger reliability in combination:
Chargers often send error signals over OCPP that indicate conditions like not being able to start charging, unexpectedly ending a charging session, and more. Keeping track of how many issues are coming in, and which chargers are reporting the largest number of issues, is likely the best way for fleets to get a handle on their overall charger reliability.
Improving the reliability of EV charging, both public and private, is one of the biggest ways we can all contribute to the adoption of EVs. I'm excited for Flipturn and our customers to continue collaborating on this important issue!