London gets wireless charging for EVs

Transport authorities hope wireless charging will increase the take-up of electric vehicles.

If you think it’s strange to plug your car into the mains overnight, then how about this for something even weirder: a recharge that’s completely wireless. Just park over a special pad, and your electric car’s batteries start to charge.

The technology has been developing rapidly in the last few years [see ‘Charging pads could keep EVs on the go']. Now it’s being piloted in London, with 50 ‘wireless-enabled’ electric vehicles (EVs) let loose on the city’s streets. The Wireless Electric Vehicle Charging (WEVC) trial will test technology made by Qualcomm that exploits a phenomenon called inductive charging to ‘refill’ EVs without any electrical sockets.

It works like this. Current passing through a charging pad in the ground generates an electromagnetic field that induces a current in a receiving unit fitted to the base of the car and connected to the battery. Many electrical toothbrushes are charged in exactly the same way. The charge time is the same as for a standard charge point and is 97% efficient. Similar systems are also being developed by WiTricity in the US, although nothing on the scale of the WEVC trial has ever been attempted so far. 

The trial is backed by the Government, the Mayor of London and the capital’s transport authority, Transport for London, all of whom hope that wireless charging could increase the popularity of EVs. “It’s attractive for public charging points because it saves space and minimises visual impact", commented Ed Metcalfe, Institute for Sustainability. 

Overcoming public suspicion of the novelty of EVs will be crucial to their success. A technology which does away with the need for charging posts and trailing wires could play a part in that. – Hywel Curtis 

Photo credit: QUALCOMM