Recharging without a cord!

An emerging company has developed a solution;

For these situations, Evatran has developed, a particular product and it’s quite ingenious: a wireless charging station using electromagnetic induction. Induction is a way to transfer energy without requiring a cable between the vehicle and the charging system.  The name of their product? The Plugless Charging System.

Electromagnetic induction is an electrical principle that is well-known and has been used in products for ages. For example, it is found in transformers: A transformer is two coils of wire wound around a “donut” of metal. Passing current through the first coil (called the primary), creates a magnetic field (as in an electromagnet). This magnetic field, guided by the “donut” core , passes through the middle of a second coil (called secondary). This creates voltage, and thus a current, in an electrical load. Therefore, it transfers the energy of the first coil to the second.
If the metal “donut” is separated into two halves and the two coils are pulled away from each other, it becomes an air core transformer, and will still function, with a (very) slightly diminished efficiency.  Charging by induction, is equivalent to an air core transformer . However, as there is no metal to guide the magnetic field, it is necessary that the secondary coil is aligned with the primary coil for receiving the magnetic field. The Plugless system‘s acceptable air gap varies between 70 and 130mm.

The inductive charging system, therefore, consists of two coils: the primary coil, which is installed on the ground, (called the parking pad), and the secondary coil, (called vehicle adapter) which is integrated under the trunk at the back of the car.  Control circuits, including a radio link, are also necessary for the communication between the two parts of the system.

The electrical grid (like Hydro-Quebec) operates at a frequency of 60Hz, but to transfer energy efficiently across the air gap, the use of a higher frequency is required. The Power system operates at a frequency of 19.5kHz.

Installation of the parking pad.
The primary coil is installed on the ground through placing it on top of three aluminum rods inserted into holes previously drilled in the garage floor or parking place. To locate the ideal spot, the driver is asked to park naturally 3 times and the installer records the average parking location.  The 3 rods are used to prevent unexpected movement of the parking pad in the event that a vehicle hits or rolls over it.  The maximum weight supported by the parking pad is 500kg (1100lbs). The parking pad can be moved by simply lifting it off the rods, for cleaning or snow removal.

The parking pad is connected to the control panel by an outdoor-certified electrical cable. This cable can be buried in the ground for a more permanent installation, or the control panel can be installed on a pedestal where a wall isn’t available.  The standard cable length is 8 meters (25 feet) but it is possible to have one longer if necessary.  It is recommended that the cable be positioned so that the car does not roll over it during parking.

The control panel requires a dedicated 30A/240V circuit in the electrical panel of the home. On the front face of the control panel, there are icons that provide the driver with parking guidance to align the vehicle correctly over the parking pad.

The driver icons include 3 Variable Speed ​​Forward arrows, one backwards arrow and one for each side to indicate the necessary movement of the car for optimal alignment. The large green circle illuminates when the driver has found the ideal alignment.  This information is very useful for the first few uses of the system, but it soon becomes second nature for the driver to correctly align the vehicle and the icons are only used for confirmation.

The system even has a digital display that provides a score, between 9 and 99 for parking precision. The numbers are also used for error codes. This can easily turn into a game between the different drivers of the vehicle. It is important to note that the efficiency difference between a high score and low score is only 2%.

Installing the secondary coil – (vehicle adapter) on the car.
The installation of the vehicle components requires a certified automotive technician, which implies that it must be done by a dealer. In Quebec, first dealer to supports this product is Bourgeois Chevrolet, in Rawdon. We went there and were able to see all phases of installation, as detailed below.

Upon initial unpacking of the components, we were impressed by the quality of parts. ALL bolts are stainless steel. The brackets are painted with a durable powder coating. All electrical connectors are certified to the OEM level and plug into the existing connectors without any cutting or welding. Everything is ”Plug and Play”.

To begin the installation, the 12V battery is disconnected. This will cause some error codes in the onboard computer when the battery is reconnected, but these will be erased by the technician with the proper OBDII tool.

A wire harnesses is connected to the positive terminal of the 12V battery and another connection is made to the brake light under the interior trim of the roof. Pressing the brake pedal is designed to  interrupt charging. A cable is then passed through a hole in the vehicle floor to the secondary coil (vehicle adapter).

Since the Plugless system simulates normal wired charging, it must reproduce the signals required to make the Volt believe it is physically plugged-in.  To accomplish this, a wire harness is passed through the bottom of the car to the traditional charging outlet on the Volt’s driver side.  The standard GM harness is disconnected from the outlet and connected to  the vehicle adapter.  Voila! The system can then simulate for the onboard computer of the Volt that the recharge the door is open, allowing it to charge, while the door remains physically closed. All wiring is protected in carlon (a flexible plastic tube). It is also installed specifically to avoid areas of heat including   by the exhaust pipe to the rear of the vehicle.

It is important to note that the car maintains its ability to use a normal wired system (J1772) at any time. A “first come, first served” strategy is used to decide which system is activated and to ensure that both systems can not charge at once.

Bruno, the technician at Bourgeois Chevrolet, completed the installation of the adapter on the Volt in 3 hours, while being trained by a certified training installer from Evatran.  It is estimated that this could be done in less than 2 hours by a fully trained technician.

We were very impressed by the quality and professionalism of the integration. 

Installing the control panel at Guy’s (the customer’s) home 
In order to install the primary coil (parking pad), an electrician must connect a 30A circuit to the control panel, which is attached to the outer wall of the house. An external electric cable connects the control panel to the parking pad. This wire is placed on the asphalt and positioned so that the car does not have to roll over it when parking. Typically, placing the control panel directly in front of the parking space does the job. The guidance system allows the driver to confirm when he is correctly aligned.

The electrician completing the installation simply has to connect the 2 phase wires and the grounding wire. It’s very simple.

The next step is determining where to place the pad by asking the owner to park the car normally three times. 

During a pre-site survey, the installer must check, with a metal detector, that there is no steel in the ground directly below the parking pad.  Concrete surfaces with significant industrial steel rebar are not currently approved for the installation of the Plugless system, though Evatran tells us that a next generation of the system will include a parking pad which is less susceptible to steel. In the case of Guy, his asphalt driveway had no steel underneath.

To prevent the parking pad from moving, the installer drills 3 holes in which the aluminum pins are inserted. These pins are used to keep the pad in place.

The installer must then pair the control panel with the the car. This ensures that only the target vehicle can be charged by the installed charging station. There can be several vehicles paired with a given control panel, which is useful for multi-vehicle fleets or local delivery vehicles. This is similar to using RFID cards to enable charging stations.

Using the system: 
Guy parked his Volt in his driveway and used the indicator arrows on the control panel to verify that he was centered over the parking pad. Then he turned his Volt off. The existing charge light on the dashboard of the Volt turned orange, then green with a little horn chirp! The charge starts instantly!  He exits his Volt, happy and proud to be “liberated” from the charging cord.
The following video shows the major steps of the installation of the parking pad and the control panel and shows Guy’s Volt when parking and charging begins.

During the first two weeks of operation, Guy found a few small hiccups.  A few times thesystem stopped charging and gave an error code 08, indicating the system’s foreign object detection system had sensed ferrous material between the coils of the system. Evatran sent an engineer on site to clarify the problem and Evatran was able to identify the issue.  Guy’s driveway turned out to be a unique installation for Evatran in that Guy’s Volt had worn divots in his driveway, which, when parked, dropped the vehicle down approximately an inch closer to the parking pad than expected by the Plugless system.  These divots reduce the height of his Volt relative to ground level, which causes the two coils to be too close to each other, causing a false detection of metal.

This was different from the over 30 installation sites used by Evatran in its trial program,  so they have incorporated this situation into a firmware update.   This will prevent the false error codes in future similar situations.
Guy is proud to report that the firmware update has resolved the false detection of metal!

It also happened a few times, two in fact, that the circuit breaker on the control panel was activated, cutting power to the control panel and charging pad, and thus the power to the car. Pressing a smallswitch on the left side of the control panel restarted charging. 

Efficiency
For ease of use, the system gets a perfect score!  As we said at the beginning of the article, however, having an air gap between the two coils leads to an inevitable loss in energy transfer. The loss is estimated at about 12%. Thus, to complete a full charge of the Volt (12 kWh), it will consume about 13.4kWh. For Guy and his wife, who travel 15000km per year with the Volt, they estimate the electricity consumption of their Volt will increase from $250 to about $280 per year, or $30 more than a normal wired system, which is cheap compared to the benefit they have in never again plugging-in. 

This system has also been scientifically evaluated by the U.S. Department of Energy.  Their report also shows that the overall efficiency is between 86.1% and 89.2%. Alignment and distance between the two coils  are the main variations in the efficiency factor. Here is the detail:
Price
Guy took advantage of a discount of $ 1,000 (U.S.) offered at the introduction of the system to the general public for the first 250 registrants. The price paid by Guy for his system was $ 1,999 (USD) ( shipping, installation, and taxes were not included in this figure). 

The base price for the Plugless System is $2,470 (U.S.) for a Volt or a Leaf (installation not included). 

Although this is not within the reach of all, some buyers who want the convenience will not hesitate to purchase.  The maximum rebate of $1,000 for the purchase of a driver’s first EVSE will also likely apply in Quebec. Incentives up to $2,500 are available in some states. 

Conclusion
The Plugless charging system, created by Evatran, seems to be a step towards convenience and a more pleasing electric car experience.  Guy is pleased with his experience, and we recommend this system for those who appreciate the conviviality it provides.

Plugless contest!
In order to bring more attention to this innovative product, Evatran  is giving away one of its Plugless  charging systems to one lucky Volt or Nissan Leaf owner in the Montreal area. Just visit the link below and enter your information to be registered. The contest is only open to residents of Quebec with residences located in the greater Montreal area (radius of 100km).

GOOD LUCK TO ALL!