This will vary according to device but generally, a full charge will take 25% longer with wireless charging than with standard cable charging. The idea however is that your device is constantly charged when you remove it from the Pebble 2 so you no longer need to think about charging times.
The size of Pebble 2 was designed to offer the best compromise between functionality and elegance. It is large enough for all supported devices to stand comfortably yet small enough to remain elegant. An embedded magnet also ensures that the device does not move around while charging.
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