If there is one thing I constantly have to think about on a pretty much daily basis, it's juice. Not the kind of juice you pour yourself in the morning at breakfast, but the kind that is needed to power by insatiable electronics on the go. Last August, Phonesuit sent me a review unit of their 1000 mAh Primo Cube, but this year they really stepped up their game and sent over a whopping 8200 mAh portable charger called the Primo Power Core, compared to which the Cube is a mere drop in the bucket.

The Primo Power Core originally caught my attention for 3 reasons:

  • imageFirst and foremost, its massive 8200mAh capacity, which should be able to recharge a 1500mAh battery over 5 times.
  • A high-current output, with juice flowing out of the 5V jack at 2.1 amps, which is 4 times the amount a computer USB port provides (500 milliamps) and should be able to rival most wall chargers.
  • For $99.99, it's priced very competitively compared to other similar products (remember both of the above bullet points).

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So, after testing the Power Core for over a month with 3 of my green friends you can see above, I've formed my opinion and molded it into sets of positives (Yay!), negatives (Nay!), and real-life tests, and topped it off with a conclusion.

Let's get to it.


  • 8200mAh - with enough capacity to recharge an average phone's battery about 5 times and a tablet 1 time and then some (unfortunately, the XOOM doesn't charge via USB - bummer), the Power Core will last a long time before you need to plug it in again. As a heavy tethering user whose battery is 50% depleted by 12pm (on the way to work), I found myself with plenty of juice for over a week. Your mileage may vary, of course, so it may last you months if you recharge only in emergency situations (or have an iPhone 4, which has stellar battery life, as much as it pains me to say that).
  • 2.1 amps - most chargers, especially on the cheap side, will provide between 500 milliamps and 1 amp of current, which translates into slower charging. In fact, some chargers won't even be able to keep up if you're running lots of power-intensive apps, and your device will still slowly discharge. I believe wall chargers are rated at 2.1 amps, and Power Core tries to match them. While it doesn't perform as well as the wall charger, it outperformed any other chargers I've tried before and charged my EVO in a speedy fashion. See the Charge Tests section below for more details.
  • Compatible with multiple devices, as it has a universal USB cord with microUSB, miniUSB, iPod, iPhone, and other interchangeable tips. I found myself needing a regular microUSB most of the time, so I didn't even bother carrying around any others.
    • The Power Core comes with a 30-pin Samsung adapter with lower resistance (newer models come with a special RC module rather than a specific Samsung bit, which is even better), which increases the amount of current flowing to the tablet. I've verified that it indeed charges the Tab 10.1 well, even with the screen on (at first it didn't charge with the screen on and displayed a red X over the battery, as I was using the regular Samsung charging cable).
  • Compatible with existing USB cables - don't like the modular USB cord that comes with this charger? Is it not long enough? Just use your own - plus it won't be as bulky on the modular end.
  • 3 LED charge indicators - all 3 light up when you have 100% charge, then they gradually turn off one by one. The Power Core charges itself pretty slowly - 3-4 hours, but hey, this is a big reservoir we're talking about.
  • Convenient shape - unlike the awkward Power Cube by the same company, the Power Core is shaped like a brick, so it's as natural to handle and use it as it looks.
  • Great aesthetics - I love the way this charger looks. The presence of LEDs is a nice touch when they're turned on.
  • Minor one - the included carrying pouch is handy.
  • $99.99 price doesn't break the bank for the capacity and high-current output you're getting.

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  • Update: As it turns out, the 2.1A, which should be able to provide enough power for tablets, such as my Galaxy Tab 10.1, simply isn't. It's not a big surprise, as my tests (below) showed the charging process to be about 20% slower than the wall plug, but the fact is - when plugged into the Tab 10.1, the Power Core does not charge it with the screen on (a red X is visible over the battery icon). With the screen off, however, the tablet does charge, albeit pretty slowly.
    Update: Disregard this bullet point completely and see the Samsung bullet above in the Yay section.
  • Single USB port - I would rather have dual USB ports instead of that extra 12V port, which requires an optional connector anyway.
  • 12V connector not included - the 12V port, which is meant to power laptops, netbooks, and the like needs a connector that is not included by default and needs to be special ordered. I was not able to test the 12V charging functionality.
  • The Power Core needs a very specific power adapter (included) - the Power Core can't use microUSB or miniUSB to charge itself, which means I can't recharge it unless I have the power adapter handy. I would have much rather preferred to have that option, no matter how slow it would be, so that I can charge it overnight at a hotel, for example.
  • Does not auto shut off after inactivity, which can drain the internal battery if you forget to switch it off (although I suspect that the draw is minimal, as no current is flowing out outside of powering the 3 LED lights).
  • $99.99 - I put the price in both Yay and Nay because while it is reasonable, there is some cheaper competition on the market with even more capacity (see the Competition section below).


Charge Tests

Because it takes months for the battery to really prove itself (it took 6 months for an off-brand Dell laptop battery to last me less than an hour) and because it's quite hard to keep track of every charge, my tests are limited to actually showing the speed of charge using AC power (left), the Power Core (middle), and a 1600mAh 1 amp charger I scored at CES.

If you examine the leftmost 30 min intervals on each graph, you'll see that the AC charger charges the fastest (about 25% per 30 min), with the Power Core following closely at about 20% per 30 min, then followed by the 1600mAh charger that goes about 13% per 30 min.

While it can't match AC power (I don't know if any charger can in real-life tests), the Power Core holds its own very well.

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Left - AC power || Middle - 8200mAh Power Core || Right - rival 1600mAh portable charger (< 2.1 amps)

Full Specs

  • Model Number: PRIMO-CORE-SP
  • Battery Capacity: 8200 mAh
  • Power Output: DC [email protected], [email protected]
  • Power Input: DC [email protected]
  • AC Adapter: 100v to 240v AC Adapter. USA, UK and EU outlet types available.
  • Dimensions: L 130mm x W 75mm x 18mm
  • Weight: 233 g / 8.2 oz


  • i.Sound Power Max 8000mAh - 1.6 out of 5 stars on Amazon, with 5 reviews. $55. Ugh.
  • Trent iCruiser IMP1000 11000mAh - 4.7 out of 5 stars on Amazon, with 48 reviews. It has more juice and is cheaper at $75, but is lacking the 12V output and seems to be rated at 1 amp instead of 2.1 amps like the Power Core. Still, it's a very strong and 25% cheaper contender.
  • i.Sound Power Max 16000mAh - 4 out of 5 stars on Amazon, with 47 reviews. At $77 (on sale), this thing is an absolute monster. 5 (!) USB ports and output current of 2.4 amps (though probably total, split between all 5 ports). On the downside, but expectedly, it also weighs more and isn't as portable, but if you care mostly about capacity, this battery pack is extremely impressive.


The Power Core by Phonesuit is my first portable charger of such high 8200mAh capacity, but I am extremely impressed with its performance after a month of use.

My devices are very power-hungry, yet I go for over a week without needing a charge.

It charges fast, a bit slower than the wall charger, but faster than any other charger I've ever tried, and certainly faster than any computer USB port.

Because its 5V output comes out of a regular USB port, you will find it compatible with all gadgets that charge via USB, whether using the included cable and set of tips, or by using your own USB cable.

The $99, while very reasonable for what you're getting, is a tad higher than I'd like it to be, especially seeing serious competitors with higher capacity chargers and more USB ports go for 25% cheaper.

If you're looking for a charger for your portable device, do your research, but know that the Power Core earned high marks in my grade book.



  • You can buy the Primo Power Core from from Amazon (currently 4.3 out of 5 stars with 7 reviews) - $95 shipped at the moment
  • Directly from Phonesuit, the manufacturer - $99.99