Most of us who lug portable devices around with us are used to wrestling with a tangle of cables. Wireless charging pads can take at least one cable out of the mix: You place your phone on the pad’s surface, and charging occurs through a technology called inductive coupling.
This technology isn't brand new. But increasingly, new phones have built-in wireless charging capability, so there's no need to purchase a case, sleeve, or back (which are sold separately) to charge. But many current phones still need charging cases—including iPhones.
What we tested
The two main wireless-charging formats found in products today are Powermat by Duracell and Qi, pronounced "chee." (There is also a third wireless-charging standard from the Alliance for Wireless Power or A4WP that has backing from Samsung and Qualcomm.)
Of the four charging pads we tested, one is a Duracell Powermat and charges up to three iPhones. Duracell also makes Powermats that charge one or two phones and models that charge the Samsung Galaxy S3 phone, but we didn't test those versions.
The other three pads use Qi, which is incompatible with iPhones but can charge other types of phones. Any phone without built-in Qi compatibility will require a wireless case or back. The Qi pads are the Energizer IC2B, Panasonic QE-TM101-K ChargePad, and LG Nexus 4 Wireless Charging Orb WCP-400.
How we tested
We first measured how long phones took to charge using an AC adapter and connecting cable, and then how long they took to charge using the pads.
We also checked the pads for water resistance: Each was sprayed with the same amount of water to simulate use on a kitchen counter, placed in a normal usage position with the pad’s AC cord connected to a wall outlet (but no phones on the pads). Any impairment to the functionality of the pad would be considered a failure—and a possible safety issue.
What we found
Of the tested pads, the Duracell Powermat was the faster charger overall. The average charging times using AC adapters for Powermat- and Qi-compatible phones are comparable: 2 hours 15 minutes and 2 hours 18 minutes, respectively. But while wireless charge time for Powermat phones was again 2 hours 15 minutes, the Qi's wireless method took quite a bit longer than AC charging: 3 hours 21 minutes.
Some pads can charge more than one phone at a time, so we tried that out too. When we charged two phones on the Energizer pad, it took 30 minutes longer than charging two phones on the Powermat. The Powermat is the only one that can charge three phones wirelessly; charging three phones on that pad took just 15 minutes longer than charging two.
As for water resistance, all four pads passed our water safety test with no problems or damage.