Progress yesterday with EV charging at the house …
Summary: on the exterior north face of the house under construction, we now have an electric vehicle (EV) charging station. I installed this charging station yesterday. This is on a 30-amp circuit so it charges an EV at as much as 24 amps. For my car this means a charge rate of 17 miles per hour. No matter what the make and model of EV, the vehicle can charge using this station.
Details: Previously I had trimmed this circuit with a NEMA 14-30 receptacle. Usually when you see this receptacle it is in a laundry room where a clothes dryer is going to be used.
When I finally thought this through, I realized that I had made a mistake trimming this circuit with a receptacle. There are at least three reasons why I had made a mistake.
Who can plug in? It took me a little while to think through that not every EV car owner carries with them at all times a travel charger, and even the EV car owner who always carries a travel charger is not necessarily going to carry around a set of adapters for every possible receptacle including a NEMA 14-30 receptacle. I’d guess that only a very small fraction of EV car owners would be able to plug in at this receptacle.
My impression is that among the handful of EV owners who do carry around a travel charger at all times, and who carry around an adapter for high-current receptacles, the receptacle that the EV owner is prepared to connect to is a different receptacle namely at NEMA 14-50 receptacle. For such an EV owner, I am not being at all helpful when I provide the NEMA 14-30 receptacle which is much less commonly used for charging of electric vehicles.
Ground-fault circuit breaker? Our electrician reminded me that such a receptacle cannot simply use an inexpensive two-pole circuit breaker. To comply with the electrical code, this receptacle is required to have a ground-fault circuit breaker. Such circuit breakers, when rated at 30 amps and 240 volts, cost at least $108. But if you select the correct charging station, you will find that some charging stations have ground-fault circuitry built in. Such a charging station can be powered by an inexpensive circuit breaker. Another way to say this is that in such a situation, $108 of the purchase price of the charging station is free.
Tax incentives. I also sort of stumbled on the fact that there is a federal tax credit in place right now for installation of EV charging stations. To get the tax credit, you have to get the charging station installed by December 31, 2020.
Picking a charging station. Having figured out that I had been unwise in trimming this circuit as a receptacle, I realized I was going to need to pick a charging station.
What kind of connector? This turns out to be the easiest thing to decide. In the United States in 2020, it is now absolutely settled that the standard plug for EV charging is the fetchingly named SAE J1772 connector, nicknamed the “J plug”. In the US, every car that is not a Tesla uses the J plug. Every Tesla car owner carries around an adapter so that the car can be charged using a J plug. From this what follows is that every EV in the US can be charged using a J plug. If you click around on Amazon looking for EV charging stations for use in the US, you will find that (other than Tesla charging stations) they all have this J plug. So you do not need to think about this at all in 2020. But there are other things to think about when selecting a charging station.
How much current? A first thing to think about is the current-carrying capacity of the charging station. Some less expensive stations would not make full use of this 30-amp circuit.
Hard-wired? A second thing to think about is how the charging station connects to its power source. Some less expensive charging stations are made so that the only choice is to plug the station into a receptacle, for example the NEMA 14-50 receptacle mentioned above. Other charging stations permit a hard-wired connection. I wanted a hard-wired connection, in part so that I could avoid the cost of the super expensive ground-fault 240-volt circuit breaker.
There is also the matter of the appearance of the installation. If you have a wall-mounted charging station that is powered by a receptacle, then there is not only the charging station itself, but also a very big fat cable dangling down from the charging station, with a big fat NEMA 14-50 plug at the end. The plug is as big as your fist. The big fat NEMA 14-50 plug plugs into a big NEMA 14-50 receptacle. The installation is visually cluttered. On the other hand if the charging station is hardwired, then it looks tidy. I wanted it to look tidy.
Integrated ground-fault circuitry? A third thing to think about is that according to the electrical code, you get a free pass on having to spend the big bucks for a super expensive ground-fault 240-volt circuit breaker only if the charging station itself provides the ground-fault circuit protection. So I had to make sure the charging station has built-in ground-fault protection. (Some less expensive wall-mount EV charging stations lack the built-in ground-fault protection.)
Connected to cloud? A fourth thing to think about is whether I need the charging station to be connected to a cloud. Some less expensive EV charging stations are basic. They deliver electricity to an EV and that is the end of it. Other EV charging stations can be connected to a cloud, and can tell you what’s going on by means of an app on your smart phone, and can be programmed to do their charging only at certain times of day when electricity might be cheaper. I decided I needed a cloud-connected charging station.
Which ecosystem to join? Once the decision has been made to select a could-connected EV charging station, this inevitably brings you to a fifth decision factor — which ecosystem to join? If you pick the “right” ecosystem that’s great. If you pick the “wrong” ecosystem, you will be incessantly annoyed by your wrong decision, and the annoyance will arise as often as once a day for years or more. I ended up choosing Chargepoint. Only time will tell whether I chose wisely or unwisely. Thus far I feel this was a good choice for me.
How did I pick Chargepoint rather than Juicebox or Amazon Basics or Siemens or any of the other popular brands of charging stations? A main reason is that I do lots of charging at our temporary housing location where there are a dozen free-of-charge Chargepoint charging stations. And from time to time I do charging at some of the other free-of-charge Chargepoint stations, for example at Whole Foods. So I already have an account with Chargepoint and I am accustomed to checking the Chargepoint app on my smart phone to see the status of the charging of my car.
If you click around to see which company has the most charging stations, and which companies are in second place or third place when ranked by the number of charging stations, you will find that Chargepoint is very close to being the only game in town, at least in the US. Chargepoint is in first place with about 114000 charging stations. The company that is in second place has only about 4000 charging stations, which is a very distant second place.
You can fire up the smart-phone app for Chargepoint, or the smart-phone app for the second-place company or the third-place company, and do a geographic search for nearby public EV charging stations. I guess this is a little bit like searching for an ATM that works with your bank, or looking to see which cell phone company has cell towers in a particular location. What I have found is that first of all there are plenty of places where you can go that do not have any public EV charging stations at all. But there are whole states of the US where the second-place company or third-place company simply does not have any charging stations at all, and where Chargepoint will turn out to have hundreds of charging stations.
Thus far, every time I have used a public Chargepoint charging station, it has been free of charge. Think about it! Free of charge. Are there any gas stations that give away free gasoline? No.
It seems to me that just about every owner of an EV in the US falls into one of two categories — the EV owner who already has a Chargepoint account, and the EV owner who will soon get a Chargepoint account. I already have a Chargepoint account. So I already have the Chargepoint app on my phone. It seems to me that every EV owner either already has the Chargepoint app on their phone, or will soon have the Chargepoint app on their phone. So for me it was pretty easy to decide on getting a charging station that is made by Chargepoint. This means that I can view my charging activity on this home charger using an app that I already have on my phone, without having to install yet another app on my phone. It shows all of the charging activity in one place.
The particular Chargepoint charging station that I selected is the Chargepoint Home Flex. It permits scheduling charging at night if the electricity is cheaper then. It has a 23-foot cable for the J plug.
Tesla charging station. The other progress yesterday with EV charging at the house was that I successfully installed a Tesla wall charger. I installed it in the garage, and you can see it here between the two garage doors. Here, too, the decision was to make it hard-wired. The hardwired choice gave me a free pass on having to upgrade the circuit breaker to a ground-fault breaker (thus saving something like $127). The previously mentioned outdoor charging station is on a 30-amp circuit. This indoor charging station, inside the garage, is on a 50-amp circuit.
To provide 50 amps of current, the wiring needs to be six-gauge wire. That kind of wire is very thick and stiff and very hard to handle.
When this circuit got wired, it originally ran to a junction box that was on the wall at about knee level. What I did was to cut a big hole in the wall above this junction box, to gain access to the cable. I then cut the cable and brought it out of the wall so that I could connect it inside the charging station. The result is a hard-wired connection and a visually uncluttered installation.
You can get the Tesla Gen 3 charging station with an 8½-foot cable or an 18-foot cable. It is the same price either way. I chose the longer cable so that it can easily reach to a car that is parked in either of the two garage bays.
This station charges at 40 amps which in my car amounts to about 23 miles per hour.
208 volts or 240 volts? One interesting thing is the voltage available at the charging station. If a charging station is powered by three-phase AC, then the station will deliver only 208 volts instead of 240 volts. This means about 13% less power being delivered to the EV. For the free-of-charge charging station at our temporary housing location, this means only about 15 miles per hour instead of 17 miles per hour.
The power in our house-under-construction is single-phase, not three-phase. Thus the voltage provided to the charging stations is 240 volts, not 208 volts.