Electric vehicle (EV) charging in the US works by using charging stations to supply electricity to EVs, which stores the energy in their batteries to power the vehicle. There are different types of charging stations that vary in speed, cost, and convenience.
Level 1 Charging: This type of charging uses a standard household outlet. It is slow, but very widely available, and typically only used in an emergency, when there are no other charging options available. Most EVs come with a portable level 1 charger (more accurately an EVSE since the AC charger is part of the vehicle).
Level 2 Charging: This type of charging is faster than Level 1 and uses a 240-volt outlet similar to the one used by a clothes dryer, or they can be hard-wired into their own circuit. A Level 2 charging station can recharge an EV battery much faster. Public level 2 chargers will typically provide 7 kW, home chargers on a 50A circuit could provide up to 10 kW, and some more recent vehicles can push that to 19 kW, assuming you have the circuit in the house to support it. This type of charging is ideal for charging at home, at work or anywhere else where the car will be parked for several hours.
DC Fast Charging: This type of charging uses a high-voltage direct current (DC) to rapidly charge an EV battery in just 30 minutes to an hour. This type of charging is ideal for long-distance road trips. Early chargers provided 50 kW, but more recent ones can provide up to 350 kW. It is important to note, however, that just because a charger says it is capable of providing 350 kW, it does not mean all cars will benefit from that. Very few current EVs can take over 150 kW, so, even when plugged into a 350 kW hyper-fast charger, they will not receive more than 150 kW. Even when a vehicle can accept more than a 150 kW unit can provide, it will not do so for the entire charging session. As the battery fills up, charging speeds will drop to prevent damage to the cells. This is why it is recommended that drivers stop their DC charges at around 80% – charging that last 20% can take longer than the first 80% took, so journey times will be reduced by stopping at 80% and then charging from a low state of charge again later, if needed.
There is some confusion about connectors used for charging, and it is the case that in the US there are two distinct groups: Tesla and non-Tesla. For Level 1 and 2, Tesla vehicles come with an adapter that lets them charge from the standard J1772 connector that all other current EVs (and ones sold in the last decade) use. Tesla also sells its own AC EVSE which uses their own connector. (If you’re installing a charger in your home or office for your Tesla, we would recommend getting a standard J1772 one since it can charge other vehicles if you switch in the future, or have a guest who needs a charge).
When it comes to DC chargers, there are three connectors you might encounter:
- Tesla’s connector (only used by Tesla vehicles and Tesla’s own Supercharger network).
- The CCS connector (used by by most other EVs that can be charged at a DC charger)
- CHAdeMO (a connector used primarily by Nissan in the US, but being phased out)
The CCS connector looks like the J1772, with some extra pins below it. It usually plugs into the same place in the vehicle, but may require the lower two pins to be uncovered on the car before connecting. Those two pins carry the high voltage, high current DC power that charges the battery.
EV charging stations are operated by different companies and networks such as Tesla (for Tesla vehicles only), Electrify America, ChargePoint, EVgo, Blink and Volta Charging. Some charging stations are free to use, while others charge a fee based on the amount of energy used or time spent charging.
EV owners can also use a mobile app or a website to locate and pay for charging at a station. in some cases, the navigation system in the vehicle will have chargers in its database, or it will be able to access an online database. Others may not have this capability, and drivers will need to rely on apps like ChargeHub EV Map (Android), PlugShare (Android) or one of apps belonging to the charging networks (I like ChargePoint’s app (Android) as it shows some other charger networks as well).
Some charging stations accept credit or debit cards, and other accept payment through mobile apps or RFID cards.
Tesla drivers can only use the Tesla Supercharger network for DC charging, unless they have purchased the CCS adapter to connect to other stations. They can still use public AC charging points using their included J1772 adapter.
For most daily driving there is no need to worry about planning a route to include charging stops. Drivers can charge overnight at home, or at work, or, if they do not have any charging options at home or work, they can visit a DC charger as needed. Depending on daily mileage, that may only be needed once or twice a week.
When making a longer trip some planning will still be needed. While the number of chargers is increasing every month, they are still not as ubiquitous as gas stations. They also tend not to be as close to the freeways as service stations are. Some EVs include route planning in their navigation systems, and will automatically add required charging stops to your route. If your EV does not do this, an application like A Better Route Planner (Android) can be used to help plan the route.
A lot has been written about the reliability of DC chargers especially. Tesla claims to have 99.96% uptime across their network of supercharging locations, but they have an interesting definition of what counts as uptime:
Tesla defines the uptime of Supercharger sites as the average percentage of sites globally that had at least 50% daily capacity functional for the year. In other words, in 2021, on average, 99.96% of the stations had at least 50% daily capacity (stalls, as we understand) fully functional for the year.Inside EVs
Other networks do not appear to publish their statistics, which makes it hard to compare, but most of them appear to struggle with maintenance. One of the largest, Electrify America, has had ongoing software and hardware problems with their network for some time now, and it is not uncommon to find people struggling to get a charger to work, or find that it randomly stops charging.
When planning a route currently, it pays to be aware of alternative locations in case the first station you stop at has long lines or is down. While the number of deployed stations is improving continually, keeping the older ones online and working seems to be something the various companies operating them need to work on.
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