Unu DX Protective Battery Case for iPhone 5

Pros Nearly doubles the iPhone 5 battery life. Thin and light. Micro USB port syncs and charges.

Cons Adds physical length to the iPhone 5. Recessed buttons can be hard to press. Bottom Line The Unu DX Protective Battery Case for iPhone 5 combines a thin and light design with a hefty battery pack, making it dollar for dollar one of the best battery cases available.

By Eugene Kim

Nearly half a year after its CES debut, the Unu DX Protective Battery Case for iPhone 5 ($79.95 direct) is finally here. It was one of the first iPhone 5 battery cases we saw, but while the company waited on Apple certification for the DX, competitors like Mophie were able to release excellent efforts like the Juice Pack Helium. The DX comes packing a relatively huge 2,300mAh battery, but manages to keep things thin and light. It turned in great performance, and is priced in line with lower capacity cases, making it our new Editors' Choice for iPhone 5 battery cases.

Design and Features
While Mophie opts for soft, rounded lines, the Unu DX features a more angular look. The beveled corners look pretty good and the soft touch finish feels great in the hand. At 5.5 by 2.5 by 0.6 inches (HWD) and 2.9 ounces, the DX is as thin and nearly as light as the 5.5-by-2.5-by-0.6-inch, 2.44-ounce Juice Pack Helium. There are cutouts for the Volume and Power buttons, with an opening for the camera around back. The buttons are a bit recessed, like on the Helium, so they're not quite as easy to access compared with cases like the Juice Pack Plus, which has built in buttons instead of cutouts. Like all iPhone 5 batter cases, the headphone jack is deeply recessed and requires the included 3.5mm extender for most headphones. The DX is available in black, white, or red finishes.

There are two pieces to the DX, but all of its guts are housed in the bottom portion, while the top is simply a plastic cap that slides on and off. Along the bottom you'll find a micro USB port, which can be used for charging and syncing. That's an advantage over every other battery case we've tested—they only allow charging through the micro USB port and require you to sync wirelessly. The button on the back serves two functions: A single press activates the battery indicator LEDs, while a press and hold activates the flow of power.

Performance and Conclusions
The Unu DX packs a 2,300mAh battery, which is significantly larger than the Helium's 1,500mAh pack and even the Juice Pack Plus's 2,100mAh battery. In my tests, making a continuous call with LTE enabled with Wi-Fi and Bluetooth switched off, the Unu DX added 7 hours, 53 minutes of talk time to my completely drained AT&T iPhone 5. That result compares well with the 7 hours, 23 minutes of the Juice Pack Plus and handily beats the 6 hours, 20 minutes from the Helium on the same test.

At $79.95, the Unu DX Protective Battery Case for the iPhone 5 is the best value out there. It's thin and light, but still adds substantial battery life for the iPhone 5. As such, it ousts the Mophie Juice Pack Helium as our Editors' Choice, providing more battery life for the same price, without adding unwanted bulk. 

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All Charged Up: Engineers Create A Battery Made Of Wood

Wood fibers are coated with carbon nanotubes and then packed into small disks of metal. The sodium ions moving around in the wood fibers create an electric current.

Heather Rousseau/NPR

The big idea behind Joe's Big Idea is to report on interesting inventions and inventors. When I saw the headline "An Environmentally Friendly Battery Made From Wood," on a press release recently, I figured it fit the bill, so went to investigate.

The battery is being developed at the Energy Research Center at the University of Maryland in College Park.

Dr. Lianbing Hu heads the group that developed a new battery made with wood at the Energy Research Center at the University of Maryland in College Park.

Heather Rousseau/NPR Dr. Lianbing Hu heads the group that developed a new battery made with wood at the Energy Research Center at the University of Maryland in College Park.

Heather Rousseau/NPR

I really wasn't sure what a wood battery would look like. I knew you could make a battery out of a potato and wires, so I figured maybe they were doing something similar with a block of wood.

Wrong. The "wood" is actually microscopic wood fibers that are fashioned into thin sheets. The sheets are then coated with carbon nanotubes and packed into small metal discs.

The wood batteries use sodium ions, rather than the lithium ions that are found in the batteries of cellphones and laptops. In this case, the charged particles move around in the wood fibers, creating an electric current. It turns out wood is a good medium for sodium ions to move around in.

Now, wood is comparatively cheap. So is sodium. Liangbing Hu, head of the battery project, says he's hoping the new batteries can be scaled up so they'll be useful for storing the vast amounts of energy generated by solar arrays or wind farms.

"I think this wood-based storage can play a very important role as a low-cost solution," he says.

Nick Weadock just graduated from the University of Maryland and helped design the new battery.

Heather Rousseau/NPR

Right now the battery is just a prototype. Hu and his colleagues will need to tweak the materials before they have something commercially viable.

There was something else interesting about the new battery: One of the authors on the paper describing it in Nano Letters was an undergraduate. What's up with that? How does a young college student wind up co-authoring a paper in a major scientific journal?

Hu says Nicholas Weadock was an engineering major who expressed an interest in working in the lab. "In the very beginning he was helping students, my Ph.D. students actually, correct some English grammar," says Hu. A lot of Dr. Hu's doctoral students are from outside the U.S. "During the process ... he asked a lot of interesting, very insightful questions, not only about the language, but about the science behind it."

Weadock says he had originally wanted to work on wind power, but became interested in energy storage technology and wanted to show Hu that he could be a contributor to the lab.

"I came to the group meetings, I made suggestions, and I was ambitious enough to show him that I can do my own project," he says.

Weadock is off to the California Institute of Technology in the fall for graduate school, where he plans to continue work on energy storage. Hu says the positive experience with Weadock has convinced him to recruit more undergraduates to his lab.

View the original article here

All Charged Up: Engineers Create A Battery Made Of Wood

Wood fibers are coated with carbon nanotubes and then packed into small disks of metal. The sodium ions moving around in the wood fibers create an electric current.

Heather Rousseau/NPR

The big idea behind Joe's Big Idea is to report on interesting inventions and inventors. When I saw the headline "An Environmentally Friendly Battery Made From Wood," on a press release recently, I figured it fit the bill, so went to investigate.

The battery is being developed at the Energy Research Center at the University of Maryland in College Park.

Dr. Lianbing Hu heads the group that developed a new battery made with wood at the Energy Research Center at the University of Maryland in College Park.

Heather Rousseau/NPR Dr. Lianbing Hu heads the group that developed a new battery made with wood at the Energy Research Center at the University of Maryland in College Park.

Heather Rousseau/NPR

I really wasn't sure what a wood battery would look like. I knew you could make a battery out of a potato and wires, so I figured maybe they were doing something similar with a block of wood.

Wrong. The "wood" is actually microscopic wood fibers that are fashioned into thin sheets. The sheets are then coated with carbon nanotubes and packed into small metal discs.

The wood batteries use sodium ions, rather than the lithium ions that are found in the batteries of cellphones and laptops. In this case, the charged particles move around in the wood fibers, creating an electric current. It turns out wood is a good medium for sodium ions to move around in.

Now, wood is comparatively cheap. So is sodium. Liangbing Hu, head of the battery project, says he's hoping the new batteries can be scaled up so they'll be useful for storing the vast amounts of energy generated by solar arrays or wind farms.

"I think this wood-based storage can play a very important role as a low-cost solution," he says.

Nick Weadock just graduated from the University of Maryland and helped design the new battery.

Heather Rousseau/NPR

Right now the battery is just a prototype. Hu and his colleagues will need to tweak the materials before they have something commercially viable.

There was something else interesting about the new battery: One of the authors on the paper describing it in Nano Letters was an undergraduate. What's up with that? How does a young college student wind up co-authoring a paper in a major scientific journal?

Hu says Nicholas Weadock was an engineering major who expressed an interest in working in the lab. "In the very beginning he was helping students, my Ph.D. students actually, correct some English grammar," says Hu. A lot of Dr. Hu's doctoral students are from outside the U.S. "During the process ... he asked a lot of interesting, very insightful questions, not only about the language, but about the science behind it."

Weadock says he had originally wanted to work on wind power, but became interested in energy storage technology and wanted to show Hu that he could be a contributor to the lab.

"I came to the group meetings, I made suggestions, and I was ambitious enough to show him that I can do my own project," he says.

Weadock is off to the California Institute of Technology in the fall for graduate school, where he plans to continue work on energy storage. Hu says the positive experience with Weadock has convinced him to recruit more undergraduates to his lab.

View the original article here

All Charged Up: Engineers Create A Battery Made Of Wood

Wood fibers are coated with carbon nanotubes and then packed into small disks of metal. The sodium ions moving around in the wood fibers create an electric current.

Heather Rousseau/NPR

The big idea behind Joe's Big Idea is to report on interesting inventions and inventors. When I saw the headline "An Environmentally Friendly Battery Made From Wood," on a press release recently, I figured it fit the bill, so went to investigate.

The battery is being developed at the Energy Research Center at the University of Maryland in College Park.

Dr. Lianbing Hu heads the group that developed a new battery made with wood at the Energy Research Center at the University of Maryland in College Park.

Heather Rousseau/NPR Dr. Lianbing Hu heads the group that developed a new battery made with wood at the Energy Research Center at the University of Maryland in College Park.

Heather Rousseau/NPR

I really wasn't sure what a wood battery would look like. I knew you could make a battery out of a potato and wires, so I figured maybe they were doing something similar with a block of wood.

Wrong. The "wood" is actually microscopic wood fibers that are fashioned into thin sheets. The sheets are then coated with carbon nanotubes and packed into small metal discs.

The wood batteries use sodium ions, rather than the lithium ions that are found in the batteries of cellphones and laptops. In this case, the charged particles move around in the wood fibers, creating an electric current. It turns out wood is a good medium for sodium ions to move around in.

Now, wood is comparatively cheap. So is sodium. Liangbing Hu, head of the battery project, says he's hoping the new batteries can be scaled up so they'll be useful for storing the vast amounts of energy generated by solar arrays or wind farms.

"I think this wood-based storage can play a very important role as a low-cost solution," he says.

Nick Weadock just graduated from the University of Maryland and helped design the new battery.

Heather Rousseau/NPR

Right now the battery is just a prototype. Hu and his colleagues will need to tweak the materials before they have something commercially viable.

There was something else interesting about the new battery: One of the authors on the paper describing it in Nano Letters was an undergraduate. What's up with that? How does a young college student wind up co-authoring a paper in a major scientific journal?

Hu says Nicholas Weadock was an engineering major who expressed an interest in working in the lab. "In the very beginning he was helping students, my Ph.D. students actually, correct some English grammar," says Hu. A lot of Dr. Hu's doctoral students are from outside the U.S. "During the process ... he asked a lot of interesting, very insightful questions, not only about the language, but about the science behind it."

Weadock says he had originally wanted to work on wind power, but became interested in energy storage technology and wanted to show Hu that he could be a contributor to the lab.

"I came to the group meetings, I made suggestions, and I was ambitious enough to show him that I can do my own project," he says.

Weadock is off to the California Institute of Technology in the fall for graduate school, where he plans to continue work on energy storage. Hu says the positive experience with Weadock has convinced him to recruit more undergraduates to his lab.

View the original article here