Price (RRP): $109.95
Perhaps I’m fussy, but if there’s one thing I hate most about Android phones, it’s plugging in the horrible charging connector. And that’s something you’ve got to do every day. The Micro-B USB plug and socket have to be perfectly aligned, and you need good eyesight to see which around the plug has to go. USB Type-C – still only on a small number of phones – is an improvement, but the ideal is wireless.
Now Belkin is out with the Belkin Boost Up Wireless Charging Pad, a more powerful wireless charger.
There are actually two wireless charging standards for phones: Qi and PMA. Some phones support both, some one, most neither. The Belkin Boost Up Wireless Charging Pad goes with Qi. Compatible with Qi are the Samsung Galaxy S6 family, the Galaxy S7 and S7 Edge – that is, the current models – the Galaxy Note 5 and the Moto Z and Moto Z Force. In addition, you can get Qi compatible “charging cases” for some iPhone models.
More on Qi shortly, but what about the Belkin Boost Up Wireless Charging Pad specifically?
This just looks like a flat disk, standing only 15mm above the desk surface and having a diameter of 115mm, or a touch smaller than that of a compact disc. It’s rather elegant with a matt dark grey surface and aluminium-look ring highlights. Belkin says that the surface grips the device. I wouldn’t go that far, but it is certainly not a slippery surface. It’s properly flat and the thing is very stable on the desk.
It has a wall wart style power supply with the cable fixed. The plug into the unit has a surround shaped to fit in pleasingly with the flying-saucer shape of the device’s underside. There are no cooling fans so operation is quiet. It just sits there and the only indication that it is doing anything is the green LED near the rim which lights up when a compatible phone is placed on the surface.
Of course, it makes the phone do something too, but we’ll return to that.
The unit can supply up to fifteen watts of power to the phone which, says Belkin, allows for faster charging. It says that most such devices are limited to five watts. It also says that it will charge through cases up to three millimetres thick.
Before using it, let’s find out a little about Qi works. A naïve implementation of wireless charging would be to have the pad generate a constantly changing magnetic field, which would then induce a current in any circuit within the field.
But a metal case of the kind fitted to Samsung phones, for example, would act as such a circuit so all the power would go to creating eddy currents within the aluminium case. A magnetic metal such as nickel or iron is not required for this. Any conductor will do.
So a naïve inductive mechanism is not good for this implementation. Instead, resonant inductive coupling is used. The magnetic field is varied continuously at a particular frequency resulting in very little effect on most nearby conductors, but which results in a resonance in an LC circuit (L is for inductance, C is for capacitance) tuned to the right frequency.
That’s what’s built into Qi compatible phones. The magnetic fields go right through the case, and tickle the reception circuit at just the right frequency to maximise transfer of power. That means that it’s safe to put other things on the charging pad. Unless they’re tuned quite precisely to the right resonant frequency they’ll receive effectively no transfer of power. In addition, the receiving device – the phone – can communicate back to the charging device its power requirements so it can control proceedings.
Well, the Boost Up Wireless Charging Pad certainly seemed safe. I put various metallic objects on it and nothing heated up. Indeed, nothing triggered it to switch on, evidenced by the LED remaining off. Later I tried putting a paper clip underneath a phone. The phone charged and the paperclip remained unaffected, apart from warming up to the same temperature as the pad’s surface and the back of the phone due to normal thermal conductance.
So I figure it’s pretty safe.