Whenever the talk turns to smartphones it's not long before the subject of battery life crops up. These pocketable powerhouses do pretty well everything these days, but the juice they need to do it runs out faster and faster the more apps you load.
My own solution is to choose a phone with a replaceable battery, but these are getting harder to find as manufacturers put fashion first, embedding their batteries in ever slimmer cases.
In this context, wireless charging is a welcome development. No need to plug in a cable, just rest the phone on a special pad or drop it into a cradle. Ikea even has line of furniture with built in wireless charging.
But it's not always that easy. Positioning the phone to get the best wireless charge, or even receive a charge at all, can be hit and miss. The US company TYLT aims to solve that with its new VÜ charging cradle. Let's see how that works out…
The VÜ charger (I imagine the diaeresis is intended to reflect the Scandinavian modality of the industrial design, although the company is based in California) is an elegant prop for your phone, Z-shaped in profile and large enough to accommodate the biggest of the new generation of handset, but not intended for tablets. Four colours are available: Black, Red, Blue and Green.
The VÜ uses Qi (pronounced "chee" – it's Chinese for "energy flow"), the wireless charging technology that's been in a 6 year old standards battle against its main rival, the Power Matters Alliance (PMA).
For consumer phones the Qi standard currently has the edge, although PMA has some technological advantages. The good news is that manufacturers are beginning to adopt dual-standard components, meaning that the VÜ should continue to be useful well into the future.
A typical problem with Qi wireless charging is positioning the phone correctly on the charge pad. It's not uncommon to come back hours later to find your phone hasn't charged at all. The VÜ's cradle construction helps get the right position, also conveniently angling your screen at 45 degrees for easy visibility on a desk or table. But TYLT's engineering solution that really nails the problem is to provide not one but three charging coils inside the chassis, making it virtually impossible to miss, whether you drop your phone onto the cradle in landscape or portrait orientation. As confirmation, a small LED at the bottom of the cradle turns from red to green while the phone is charging.
Of course your phone will need to be suitably equipped. Some, like the Lumia 930 come with charging coils built in. Others, like the recent Galaxy Notes and S series need the addition of an almost paper-thin accessory that slips between the chassis and the rear cover. Even phones without special provision for wireless charging can get into the game with receiver coil equipped cases.
The manufacturer's marketing material suggests that the VÜ should provide the same power as any standard 1 amp USB charger and will charge as fast. Typical wireless chargers operate at around 70% efficiency (wireless charging takes around a third longer), so this is quite a claim.
In practical tests my Galaxy Note 3 took almost exactly 5 hrs to charge from 2% to 100% when placed on the VU. Wired charging from the same baseline took just a fraction under 3 hrs 15 mins. Taking the ratio of the reciprocals of these figures indicates the VU is operating at about 65% efficiency in comparison with direct wired charging.
Which is about what I would expect of a wireless charger, although it didn't seem to match TYLT's claim.
But these tests were carried out on the VÜ without taking the phone out of its flip notebook case, thus adding a few millimeters of separation between the charging coil and the receiver. VÜs support literature says the device is meant to be used like this, and if you're buying into Qi for the convenience you'll probably be happy to sacrifice the odd few percent of charging efficiency. I certainly am.
When I repeated the tests with my Lumia 930 (this Windows phone never leaves the house, so remains unencumbered by a protective case) I found TYLT's claim entirely accurate – the time to 100% battery was, within a minute or two, exactly the same for wired and wireless charging.
There's a small trade-off to make this rather remarkable feat possible: you can't just plug in any old microUSB power supply you happen to have lying around. And you can't even do this accidentally, because the VÜ power input socket is co-axial to fit its own special power unit.
It's probably just as well that the UK power unit boxed with the TYLT kit is going to remain out of sight below your desk or bedside table, because it frankly doesn't match the elegance of the cradle itself.
TYLT levelled with us on this, agreeing that: "…the power supply does not meet the design standards we set at TYLT. Unfortunately the cost to create and certify a UK plug prevented us from creating our own, which left us to choose from available power supplies."
The challenge is that the power supply has to output 12 volts to feed the three coils. Ordinary mobile phone power supplies get by on 5 volts, the voltage limit set by the microUSB standard. Faced with the limited choice of UK power supplies fitting the bill, TYLT settled for this, as "the best looking and smallest solution".
In my opinion this isn't a show-stopper (the strangely wide plug will work without overlap, for example, in the kind of wider spaced double socket that has switches in the middle.) TYLT says they've found a new power supply they like better, which they'll be including in the next UK VÜ production run.
The VU's an elegant and convenient presence on your bedside table or desk, charging your phone at a rate that closely matches plug-in power. Priced a shade under £65 (Amazon, but shop around) it's not cheap, but it's clearly built to last, and will be effortlessly powering your phones for the next several generations.