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Wireless Charging Reduces Battery Lifetime

There’s been a little bit of a stir around the process of wireless charging recently. OneZero, in a collaboration with iFixit, analyzed exactly how inefficient wireless chargers are.  “In my tests, I found that wireless charging used, on average, around 47% more power than a cable,” notes the author Eric Ravenscraft. 

• “Charging the phone from completely dead to 100% using a cable took an average of 14.26 watt-hours (Wh). Using a wireless charger took, on average, 21.01 Wh. That comes out to slightly more than 47% more energy for the convenience of not plugging in a cable. In other words, the phone had to work harder, generate more heat, and suck up more energy when wirelessly charging to fill the same size battery.”
• Even misaligning the changing coils just slightly would cause more losses.
• When the wireless charger wasn’t being used, it’d still draw very small amounts of power, but that’s waste.
• Given the annual cost of charging your phone is under a dollar (ZDNet), adding 50% more to the bill isn’t a personal problem. But on a global scale, where billions use a phone every day, that power demand does cause additional capacity problems from the grid.

Ravenscraft takes things to the limit, explaining if we all switched to wireless charging, we’d need more power plants. The math is very rough, but in a general sense, we’d need more megawatts.

• Some good background on how wireless charging works.
• Not everyone is going to switch to wireless charging, unless the industry transitions more towards phones without ports, as has been kicked around for a few years.
• Wired charging is still the way to go for fast, efficient charging.
• And actually, the very best way to charge a phone efficiently and cheaply is slowly, with a cable, plugged into the wall. It’ll also help extend battery life.
• High-power, high-efficiency chargers already exist, like this system for charging electric vehicles at 120kW and 97% efficiency, while for smartphones land, OPPO promises a special new wireless charger at 98% conversion efficiency — untested at the Android Authority labs, as yet.
• A cheap, less efficient wireless charger for $16 against a much more efficient design for $160 is a no brainer as to which will sell, given the running costs of the low-quality option amount to paying just a few more cents a year

​In any case, don’t throw away your wireless chargers. And hope the industry doesn’t shift further towards wireless charging while the benefits are small, and the wider implications significant.