Are you tired of getting tangled in charger cables and fumbling around with those micro-USB plugs and sockets on your cellphone or tablet? Well, here is an introduction to wireless charging -a new mobile device charging standard -that’s sure rid your life of several feet of cables. And, you will never again need to fear that you are sure to permanently damage your mobile device while trying for the umpteenth time to connect that truly micro micro-USB cord. All you have to do is use your Qi (pronounced ‘chee’). No martial arts skills required though!
Here is a review of the RAVPower wireless charger, complete with instructions on how to set up your phone for wireless charging, and a list of the pros and cons of opting for wireless charging.
What is Wireless Charging?
The Qi wireless charging system works on the principle of electromagnetic induction whereby two planar coils of wire are paired and linked by way of magnetism. One coil is in the base unit or power transmission pad and the other in the device to be charged. The base unit is plugged into an electrical outlet, its coil becomes magnetized and this magnetic energy radiates a few centimeters above the unit.
The unit is able to sense when a mobile device (such as a smartphone, tablet, Bluetooth® headset, camera, or portable power pack) which uses the Qi standard, and therefore has a compatible receiver, is placed on top of it. After a short check for compatibility, the device’s coil absorbs the magnetic energy from the base unit.
A microcircuit attached to the coil then converts this magnetic energy into electrical energy and the device’s battery recharges. The compatibility check involves ensuring that the correct value of current is drawn by the mobile device. The Qi charger will provide exactly the amount of energy the device would draw if it were plugged into a wall outlet.
The RAVPower wireless charger which will be reviewed here (and all similar chargers) uses the Qi wireless power interface which was developed and backed by the Wireless Power Consortium. The Consortium which comprises Asian, European, and American companies in varied manufacturing industries, seeks to establish a global standard for the inductive charging technology used in the Qi wireless power interface.
More information on the Qi charging system can be found at Wikipedia entry for Qi – Inductive Power Standard. If you need anything from an introduction to wireless charging to more technical power schematic sheets explaining Qi charging, then visit Wireless Power Consortium.
Using Qi-based Charging
Qi based charging requires a Qi charger and a Qi-enabled device. Some newer devices known as “Qi Integrated” devices come Qi-enabled. That is, they have wireless charging built-in. Some examples of devices that come Qi-enabled and hence require no modification are Google’s Nexus 4, 5 (phones), and 7 (tablet). You can easily check whether your device is Qi-enabled by doing a simple search engine query for your particular phone model and the term ‘Qi charging’.
Devices that are not Qi-enabled may in fact be Qi-ready. That is, they contain secondary battery contact points for the attachment of the Qi add-on or some other power source. This can be done at a cost of roughly $10-15. That’s the price of an add-on to upgrade them for Qi-charging. Since there are as yet many more Qi-ready than Qi-enabled phones, it’s quite likely that you will have to add a charging coil to your phone.
This review of the RAVPower charging unit paired it with the Samsung Galaxy SIII which is not Qi-enabled but is Qi-ready. So, first step was to purchased and attach an add-on module specifically designed for the device. The contact points in Qi-ready devices are not placed according to any standard, so you will have to ensure that you purchase one that is made to work with your particular device. Another search engine check for your phone model and the term ‘Qi charger’ should be sufficient to point you in the right direction.
Now allow us to show you just how simple the Qi upgrade process really is. The photograph shows the phone(at center) with its back covered (and placed at left) removed alongside the SainSonic brand Qi add-on (at right). To attach the add-on module we simply lay it atop the SIII so that its gold contacts line up with the contact points of the phone.
Here is a picture of this setup with module slightly askew so you can see how well everything lines up. Next is a close up of the module’s underside, showing the pair of gold contacts. The gold contacts fit so neatly into these indentations on the phone that the two sided adhesive that it comes equipped with really isn’t even necessary. Replacing the back of case also adds pressure to the contacts, ensuring that they are firmly pressed together indeed.
The add-on module is so slender that once the phone is reassembled, it is virtually impossible to detect its presence. The phone looks just the same with no visible humps or points where the back of the case is not firmly connected to the body of the phone. The only discernable difference is a very slight bulge you feel as you run your fingers down the back of the case. And make no mistakes, the SIII is quite a slender phone, so our concern about the add-on module distorting it shape was quite a legitimate one. Glad to say the module passed that test.
Our phone is now Qi-enabled (ready for wireless charging), so the next step is to examine the wireless charger itself.
The RAVPower Qi Travel Charger
The charger comes at a cost of $30 and is the perfect size to tuck away in your pocket or in an overnight bag. At a glance the unit may appear too small for the task at hand, since its width is the same as that of the SIII and it comes in at only half the phone’s length. Rest assured as we discovered there is no danger of the phone falling off the unit or not aligning properly for charging.
The unit’s design incorporates a grey ring of non-skid rubber around the power logo in the center of the charger to ensure that the phone sits securely when left to charge. For a bigger and roomier charging pad that completely supports the phone, you may opt for the RAVPower Qi Charging Pad at a cost of $36. It measures roughly 4×6 inches compared to the 3 inch circle of the RAVPower Qi Travel Charger.
A USB wall transformer comes with the charger, so you may plug it into the wall or you may choose to connect it to a suitably powered USB port on a computer. Next you sit the phone or other Qi enabled device on the charger and that’s that. The charger turns on and begins transmitting energy by induction to the device once Qi compatibility and the energy requisites have been calculated. The charger and phone remain in contact and automatically switch into standby mode the instant the battery is fully charged.
A Case for Case Thickness?
One of the main complaints lodged by consumers is that thick cases cause the induction coil in the device and the power coil in the base unit to be so far separated that the device fails to charge. We found this was not an issue, even with the thick Otterbox case made of plastic and silicone which we used on the SIII. The phone charged perfectly fine in its case, using both the both the RAVPower charger and the SainSonic brand battery module we were testing.
The Pros and Cons of Wireless Charging
You will admit that not much effort is required to upgrade your phone or to use the wireless charger but you may be wondering if it is worth setting up for long term use. Here’s how we see it:
Newer phones are manufactured to the current standard and hence are Qi-enabled; and you can upgrade an older phone for about $10.
Eliminates fumbling with the charging cord and it’s too tiny plug; no more constantly plugging in and out and worrying that you’ll damage the micro USB port.
As effective as a conventional wall charger, since we could measure no difference between the RAVPower charger and the wall charger in battery charging.
Incredibly easy to use. Just plug it in and place the Qi-enabled device on the base.
It’s super convenient since Qi chargers and Qi-enabled devices are entirely cross compatible. Good news – especially for those of us who can never seem to find the phone charger cable. Your Qi-enabled device will work on any of your friends’ charging base and vice versa, since a single charging base is able to recharge a wide range of mobile devices.
There is an increasing number of Qi hotspots being set up in airports, coffee shops, sports arenas, etc. or on one at any of
Apprehensions about the small size of the RAVPower travel charger’s base were baseless (no pun intended); despite its small size, it aptly held large phones.
It is energy saving, since the Qi charger base unit will only activate and transmit energy when a device that is both Qi-enabled and in need of charging is placed upon it.
Regardless of the convenience it provides, the $30-40 price tag on the charging base may seem a bit pricey to some people.
Heat production is an almost inevitable side effect of any energy transfer system, and so it is with the Qi charging base. Theoretically, this generated heat could reduce your phone’s battery life, but that effect is extremely minimal.
The convenience of the Qi charging base is also a possible issue in reducing your phone’s battery life. It is tempting to just rest it back on the base after each use but the life of the lithium-ion battery (found in most mobile devices) is reduced with frequent recharging when the battery has been barely depleted.
We think it’s great! Qi charging is extremely convenient and our doubts as to whether it would work with the phone case or work at all (since our phone was not originally Qi-enabled) have been erased. The RAVPower unit that we reviewed gets high marks also as we found it worked just as well as the wall charger while being so much more user friendly.
We could be picky and say it. The only downside we can relate is that Qi wireless charging could shorten battery life. But before placing too much emphasis on that we must bear in mind that a replacement battery for the typical phone is only about $10. Added to that is the fact that it would take several years for the heat and frequent recharging to actually have any discernible effect.