Since 2019, Link Transit in Wenatchee, Wash., between Seattle and Spokane, has tested a city bus with an inductive charging system.
To add electricity to the vehicle's battery pack, the driver simply drives directly over a magnetic pad placed in the ground, matching it with a magnetic pad on the undercarriage of the bus. Electricity flows from the ground pad to the pad on the bus—not unlike how some cellphones can be charged.
The driver never gets out of the vehicle and never touches a cord or a charging machine. Once the bus is in the proper position, the charging process is fully automatic. Weather does not affect efficiency.
"There could be six inches of snow, rain or ice on the ground. The climate doesn't matter," Ed Archer, Link's maintenance supervisor, told Automotive News.
For about 10 years, some cellphones have been able to charge wirelessly when placed on a pad connected to a power source. The pad contains a transmitting coil that creates a magnetic field. That field causes an alternating current in the receiving coil in the phone, which charges the battery.
The automotive version of inductive charging works much the same way, with one key difference: space. Vehicle undercarriages can't be so low that they physically touch a pad on the ground. The Link system, made by Momentum Dynamics of Malvern, Pa., uses resonant induction that aims the electricity precisely to the battery receiving points instead of radiating it. Momentum has patents for its charging technology. How the electricity travels from the grid to the battery pack does not affect the batteries.
"There really should not be any impact on battery life or performance from the induction process, as long as the system is sized appropriately," said Josh Payne, executive director for engineering at American Battery Solutions in Springboro, Ohio, "and the monitoring system is electromagnetically shielded to properly ensure there are no field affects."
Jaguar Land Rover last month announced it is working with Momentum Dynamics, the city of Oslo in Norway and several other entities to test a fleet of Jaguar I-Pace electric crossovers fitted with inductive charging systems.
The first wireless charging pads will be installed at Oslo's central train station. Three other locations in the city are planned. In all, 20 I-Paces will be tested with the goal of determining how many pads are needed in the ground and how far apart to space them so that the I-Pace crossovers can imbibe enough electricity to stay in service all day.
Momentum expects that the first consumer EVs capable of inductive charging will be available around 2025.
In Wenatchee, the inductive charging test has gone so well for its bus, Archer said, that Link has ordered nine more electric buses and hopes to have them in service by the end of the month.