A couple of weeks ago, Engadget ran a piece on a new product from a company called Phonesuit aimed at smartphone users with MiniUSB and MicroUSB charging ports (this should cover every Android phone as far as I know). Shortly after Engadget's piece, we were contacted by Phonesuit and offered a review unit, which we gladly accepted.

This contest is now over. We have selected the winners - see if you are one of them towards the bottom of the page.

What Exactly Is PrimoCube?

Primo Battery Cube, or just PrimoCube, is a $40 device that attaches to your phone's MicroUSB or MiniUSB power port and feeds it delicious juice - 1000mAh of it at full charge to be exact. The Cube also has 2 inputs that allow for both MicroUSB and MiniUSB charging of the Cube itself, so you can refill it using your existing phone charger or a computer USB cord.

When your phone needs extra juice, just open the cube to reveal the correct charging connector and plug it in in place of the charger. 4 LED lights, each representing 25% of the total charge, will light up and show you the approximate charge state of the Cube.

Considering an average handset battery is about 1200-1500mAh and the PrimoCube is 1000mAh, expect to see your battery charged up to about 66-80%.

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My Impressions And Thoughts

Having carried around the Cube in my backpack for about a week and using it a few times on the go, I can tell you that it works exactly as described. I couldn't think of a better way to provide my impressions than to list them as pluses and minuses, in my favorite bullet point style.


  • The cube is more universal than an extra battery. An extra battery is likely only going to fit a specific phone but the Cube, which is compatible with both MiniUSB and MicroUSB ports, covers a whole host of devices. Thus, I can charge my bluetooth headset or my wife's phone with the same device. iPhone/iPod users are out of luck due to a proprietary connector (though Phonesuit offers a different product specific to Apple devices).
  • You don't have to turn off your phone in order to get more juice, whereas if you want to replace the battery, you will lose the call you're on or the hotspot session you've already established to upload that Youtube clip of your dog slapping your cat Powerpoint presentation your job depends on. In fact, that's probably the biggest benefit of buying something that attaches externally compared to an internal battery. Likewise, if you have a case on, you would have to struggle to take it off when replacing the battery; with the Primo Cube, you just need to plug it in (thanks, Mike).
  • Aesthetics - this little device is very polished and pleasant to look at and play with, unlike some other products we've seen that look like they cost about 5 cents to make. The LED charging indicator is a nice touch, done in a pretty original way. In fact, the whole Cube looks like some sort of a cool media controller that you've attached to your phone - I can pretty much guarantee that you will get asked about it. I also found that I wanted to play with it if I held it in my hand, which may be bad news for this little guy in the long term.
  • Seems to charge just as fast as the AC power source (in other words, your wall plug), unlike laptop USB connectors that could take ages, depending on how much juice they put out.
  • It can be charged via both Micro and Mini USB, so I don't have to look for the right cable.


  • PrimoCube could have come with more juice - it's only 1000mAh. That's a bummer. It'd be a lot better if it could at least charge my battery in full. There is a 2000mAh version called MiLi available, though it's no longer shaped the same way and costs $20 more ($10 more right now because it's on sale).
  • The price: $40. This is pretty steep. On one hand, it can't serve as a replacement for a single battery (OEM batteries cost about $30-40); on another hand, it's a lot more versatile, as I already mentioned. Thus, in my opinion, if you compare it to an OEM battery, the price is pretty fair. However, compared to this great package of 2 batteries + charger that I found on eBay and have been using for weeks, which cost only $10 shipped, the $40 Cube no longer seems like a winner. But then again, I'm comparing to something probably made and sold directly from Hong Kong. For about the same price, I could have 4x 3000mAh batteries for my EVO 4G + 2 chargers.
  • The shape of the Cube is both cool and awkward at the same time - it's slightly fatter than the phone and doesn't provide a custom fit, instead kind of dangling due to the 180 degree flex around the charging connectors. However, if it weren't flexible, those ports would be sticking out and poking me left and right. Alas, no locking mechanism is available to prevent this rotation. I am also worried that because of the above, I may accidentally snap the connector off.
  • It could be really awkward to talk on a phone which has a power connector located on the side, like the Blackberry there in the screenshot
Update: After only about 4 months of light use, the connection between the cube and my phone started to get wobbly only charged in a certain position, eventually pretty much failing. While the company stood behind the product and promptly sent me a replacement, I can't say I would continue to recommend the Primo Cube due to its high price and awkward shape that ultimately resulted in its death.

Overall, I'm quite satisfied with the Cube, and I would definitely recommend it as a backup power source that you can throw in your bag and forget about until that evil red battery notification pops up during your call with your mother-in-law (it would be so awful to lose that call).

P.S. PrimoCube is actually shaped as a square prism, not a cube (a cube has all sides equal) but I'm guessing PrimoSqurePrism wouldn't fly with their marketing department.



You can buy PrimoCube from Phonesuit's website.


After I wrote the review, I approached the folks at Phonesuit, and they agreed to sponsor 2 free Primo Cubes worth $40 each.

And the winners are:

  1. Alex Brunetti
  2. Jagadiswar Reddy Jaggari

Emails have been dispatched notifying them of how to collect their winnings.

Thanks for playing!

How To Win

Entering the contest is really simple - just make sure you complete both steps 1 and 2.

Step 1.

There are 2 ways to play: complete either one of them to be eligible or both to double your chances of winning.

Reading: PrimoCube review by @AndroidPolice - http://bit.ly/ap-primocube - RT to win one. #Android


Step 2.

Fill out this form, so that we know who to contact in case you're a winner.

Again, both steps 1 and 2 are required to enter.


The contest starts immediately and runs until September 2nd, 11:59PM PST.

Winners will be announced here and notified via twitter, Facebook, or email.

Good luck everyone, and feel free to share your impressions of the PrimoCube in the comments.


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