Review: Primo Battery Cube

It happens without fail at least once a week. I install a new piece of software on my phone, or read a book on the Kindle app, or I get caught up in too many IM conversations…and I run my battery down mid-day with no access to a charger for several hours. Oops. Luckily, there’s products like the Primo Cube to provide extra battery boosts. How well does the Cube do? Read on to find out!

Physically, the Cube is tiny! I was shocked when I held it in my hand. It’s really small and incredibly pocketable. I was able to carry it around in the same pocket as my phone and forget it was even there! Primo also packed a remarkable amount of connections and ports into a small space. There is a mini-usb and a micro-usb charging port along the bottom panel, and hidden on the back are two pop-out charger heads, again mini and micro-usb. These rotate 180 degrees for easy access, and hide behind a small rubber door. Overall, from a build quality standpoint the Primo Cube is top notch. The only major peeve I have is with the mirrored surface on the front, which attracts fingerprints like crazy. On the other hand, the surface hides a handy LED square that lights up as the Cube itself charges and as it charges your device. From a dead to charged state, each “corner” of the square lights up until all four are flashing, and you know it’s charged. When charging your device, the reverse is true; the corner lights go out as the Cube discharges and your device charges.

More important than how cute and small it is, though, is how well it functions as a backup battery/charger. I tested it three times under different scenarios to see how it worked with my Motorola Droid. First I let my Droid drop down to around 20%, then I plugged the Primo Cube in and left it alone. After about an hour and a half, the Primo was dead and the Droid was charged to roughly 80%. Not bad. In the second trial, the Droid was at the same point (20% left) and I used the Primo while still using the Droid to read a Kindle book. In about an hour, the Primo was dead and the phone was at 60%.

Of course, then there’s the times you run your phone until the battery is completely dead. Primo Cube was able to wake my phone from completely drained and charge it until around 30%. It took around 2 hours to kill the Primo Cube, and while 30% wasn’t enough to buy me more than a few hours, it was still good to know that in an emergency you can revive a dead phone and buy a bit of time for phone calls, texts, etc.

From a convenience standpoint, recharging the Primo Cube is also very easy. Just plug the included micro-usb cable into the Primo and the other side into your USB on your computer, and it charges within a few hours. I didn’t scientifically time this, but I found that plugging it in when I went to bed (same as my phone) meant that the Primo was ready for another day when I woke up in the morning.

I had two concerns when using the Primo to charge my Droid. One, it really works better if the Droid is left alone not only for the increased battery charge, but also because the Primo is awkward. While you can angle it to a connection that keeps it stable, the location of the charging port on the Droid makes it really difficult to use comfortably. In addition, the Cube gets very hot while charging the phone. Not hot enough to burn you, but warm enough that it radiates noticeable heat while charging.

Overall, the Primo Cube is a great item to keep handy in your gear bag. While it won’t take a smartphone from dead to 100% charged, it will keep you topped off when you aren’t around a charger. The tiny size, standard and near-universal connection options, and overall quality make it a no-brainer to keep you from disconnecting from the world.

What I liked:
-USB connectors for compatibility with many devices
-180 degree connectors make it convenient to fit to devices.
-Enough power to charge from a dead battery
-LED readout is bright and easy to use.

What I didn’t like:
-Only charges about 40% of the Droid’s battery.
-Gets very warm during use

Primo Cube is available directly from Phonesuit for $39.99.

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