Power Struggle – Wireless Charging
David Simpson 12th Sep 2018 4 Min Read
In the charging zone, wireless might be the buzzword but plugging-in is the smarter choice.
Wireless charging is currently being vaunted across the media as the holy grail of electric vehicle (EV) adoption. I have my reservations, though. Yes, at first glance, it is a fuss-free technology that is capable of charging an electric car in only a few hours. But, I would argue that wireless is actually less convenient, less efficient and less stylish than the tried and tested plug-in option.
A major draw of the wireless root is the ability to dispense with the ‘charging anxiety’. Like remembering to plug in for the necessary evening re-fuel but – believe me – there are plenty of worries to replace that with. Consider the following challenges to the joys of cable freedom.
A MOBILE PHONE PRECEDENT?
Wireless charging has failed to gain a foothold in the mobile phone industry. A sector that on first glance, would appear an easier market to crack. For several years, phone manufacturers have offered the technology using the Wireless Power Consortium’s Qi standardisation. However, adoption has been patchy. Reasons for the reluctance include everything from the high cost of the technology and slower charging. The mobile consumer is still hanging on to the cable, waiting for improvements in convenience and performance.
LIMITED ENERGY EFFICIENCY
When you cut the cord of plugged-in charging (and opt for wireless), you cut your green credentials. By removing the direct connection to the wall socket, efficiency is reduced. On the face of it, the up to 90 percent energy efficiency claims of wireless charging sound good. Yet there is still a 10 percent loss in energy efficiency. In the context of mass adoption of EV on a global scale, that translates as a massive waste.
And on that energy efficiency note: in a world where politicians are keen to score points on hot issues. It is worth thinking about any future legislative implications too. It wasn’t long ago that the humble set-top box – with its comparatively high energy usage – fell foul of European Commission eco-design requirements and manufacturers were forced to make changes. Will wireless charging also run the risk of failing to meet such criteria?
SAFETY
Wireless charging uses an electromagnetic field to transfer energy between two objects – the charger to the receiver. In the case of wireless EV charging, largish copper induction coils are used in this transferred energy to the car’s battery. Sounds neat, but I think there are safety concerns around wireless charging. Exposure to electromagnetic radiation. Let’s imagine a scenario of a pet or a small child crawling under the car during charging – is the technology really hazard-free? Electric car charging devices are, after all, one of the most energy-consuming pieces of equipment in the home. Can we really be assured that all the health concerns have been properly researched and understood?
COMPATIBILITY
We have only just seen the ratification of a common EV charging standard led by Audi. Do we suppose that everything in the highly dynamic EV market is going to meet that common standard? There is also the question of vehicle compatibility with the transmitter pad. Current charging pads are – in my view – complicated to use with the need to park a car in an exact spot in order for it to charge. And, in order to achieve maximum energy efficiency, pads need to be in close proximity to the vehicle, something that is hard to achieve with the increasingly popular SUV.
INSTALLATION
Wireless charging pads are essentially bulky ramps. Installation within an EV owner’s property can be disruptive – think ripping up driveways and to re-lay paving stones. Arguably, you could put your charging pad in a garage, but who uses a garage to park their car in these days?
AESTHETICS
A big appeal of wireless is that fussy cables and connections will be all but undetectable to the human eye. However, I would argue that an EV wireless charging unit is a needy candidate for a style makeover. Bulky and obtrusive, the engineering principles of wireless mean units need to be raised off the ground in order to function. And the image problem doesn’t finish there: wireless charging for EV still requires a big ‘wall dock’ box on the wall.
The take-home message: wireless charging is a nice idea in theory but until technology moves on, it will remain niche. In my view, plug-in charging will continue to offer more freedom, flexibility and reliability, all at a lower cost.
David Simpson
A hands-on design engineer, David is responsible for driving the latest design, engineering and software developments. His experience ranges from hi-fi product design to the programme management of complex financial service software. When he’s not talking about firmware updates, tooling or road maps you’ll see him running in Hampstead Heath or ferrying his kids to school on his electric bicycle.
