Taken from : //www.macnn.com/reviews/energizer-qi-charging-pad-and-iphone-case.html

Energizer Qi Charging Pad and iPhone case

April 9th, 2011
Energizer aims for a true universal wireless power adapter.

Inductive charging is theoretically the holy grail for convenience, and the young-in-the-tooth Qi standard promises to make it relevant for nearly any low-power gadget. With that in mind, Energizer is stepping up with the Inductive Charging Pad, a plate that can potentially power anything while going wire-free. We'll find out in our full review if it's the breakthrough it's meant to be or if there's still some big caveats at hand. The plate and the Qi standard

There's thankfully not much mystery to the Inductive Charging Pad itself. Once plugged in, there's lights to tell you which of the two plates are active. Energizer drives home that the plates are direction-independent; you can put a device on a plate at any angle and it will work. Perfect alignment isn't necessary, either, although the big "Qi" logos serve as guides as to where you should generally sit your device.

The basic concept isn't that different from a device like the Powermat for iPhone: as with all inductive chargers, you need only a device with an appropriately designed back that can absorb the electricity directly, instead of having to use a wire. What's different here is Qi. Made by the Wireless Power Consortium, it essentially guarantees that any device chewing 5W of power or less can recharge from a Qi pad as long as the device was either designed for it from the start or (more likely) given an adapter to work. In our view, Energizer is wisely hedging its bet as much as it can by making sure that a competitor's pack or a new device will work immediately.

Our complaints about the basic design are few, though there is one glaring issue: how it handles a full device. We discovered that it will stop power once the hardware is fully charged. That's acceptable if you're there to scoop up the device and put it to the side, but if you're not, any device that makes a sound when plugging in will make that sound every few seconds until it's removed. With the iPhone we were using, that became genuinely annoying rather quickly.

Hopefully, Energizer could solve this by changing the behavior, such as through a trickle charge or even just forcing it to refuse a charge for a longer period when a device has been topped up. Until then, though, we'd strongly recommend you put the charger somewhere besides your bedroom.

The iPhone case

In our situation, we were testing the iPhone 3GS case. There are iPhone 4 and BlackBerry Curve 8900 cases available, as well as upcoming (as of this writing) micro/mini USB adapters to accommodate just about anything else. All of them have roughly the same power characteristics and should charge inductively about as quickly as if you'd used an AC adapter, so recharge time thankfully isn't an issue here.

A casual look at the iPhone case would give very few clues that it's a power case; it resembles any other hard plastic protector apart from the thickness. The only real giveaway is the thickness, which is more akin to a thin battery sled like the Mophie Juice Pack Air and not a real obstacle. It won't be a great fit in tight jeans, but it was comfortable in our regular pants. iPhone 4 users can expect a slightly more accommodating design.

For the most part, accessibility isn't an issue. Mute and volume controls are easily reached, and both the camera and sound go unblocked The sleep/wake button is a bit more difficult to reach but not a major issue in the long term. We liked that the case was very easy to attach or remove, and it left the iPhone untouched (that we could tell) after repeated inserts.

Much to our chagrin, however, there's no pass-through for the Dock Connector. We know that it's necessary to charge the iPhone, but without either a direct docking port or a mini USB port to work from, you have to remove the case every time you want to sync with your computer. That's not a huge issue if you only update the phone periodically, but if you sync daily, it could get very tiresome, very soon.

We'd also add that, like any other case of the kind, the screen goes unprotected. If you're the sort to drop your phone, you'll want to avoid this case and go looking for a docking cradle instead so you can get a pouch or sleeve.

A note on other adapters

How elegantly you get your power does vary widely from device to device. The BlackBerry Curve 8900 door is actually the best so far because it has the least amount of intrusion. It doesn't occupy the USB port, so you can remove the phone from the charger and plug it into your computer without having to pry the case off.

Unfortunately, it's in the minority right now. Neither of the iPhone cases free up a connection for USB, and the micro/mini USB connector of course occupies what you'd use for sync. While this might be to prevent users from trying both USB and the Qi power at the same time, it also makes the adapters a hassle. The Inductive Charging Pad will make the most sense when more devices can simply use special battery doors or even come with support built-in. We'll be curious to know if the HP Pre3 and Veer will support Qi in any way.

Wrapping up

How much you'll like the Inductive Charging Pad depends entirely on your habits. If you link up with your computer only occasionally and are generally good about keeping your phone off of the ground, there's a lot to like about the plate. If you've ever come home from a long day at work wanting nothing more than to set your phone down and forget about it, Energizer has you covered.

With the lack of a data pass-through and the behavior at full power, though, it's not the best of all worlds yet. There's also the matter of price. At $90 for the dual-device charger we tried here plus the $35 for the case, you'll have spent $125 to save a few seconds each time you plug in. And without a truly universal adapter -- not Energizer's fault, strictly speaking -- you may have to spend money again if you're an iPhone or BlackBerry Curve 8900 user. There will be a single-plate charger coming soon that should be a better value, but it's not out yet as we write.

As such, the pad is good if you fit into that broad, mainstream category of users who doesn't upgrade phones often or sync religiously with iTunes. If you update your hardware or software frequently, though, you'll want to pass; it's easier to use an official dock or just to leave a dangling power cable.

- Very simple design.

- Omnidirectional pads.

- iPhone case subtle, easy to put on.

- Charges at a normal speed.

- No Dock Connector or USB ports on the cases.

- Doesn't handle a full charge gracefully.

- Expensive for the convenience.