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Review: MiLi Power Crystal for iPhone

The biggest selling points of the MiLi Power Crystal are its size, ridiculous feather weight, and awesome, modular cable tips. I ‘ve seen plenty of USB-based external batteries that happen to be iPhone-compatible, but I think it’s pretty rare to see a 2000mAh battery and so many little extras in such a slim $45 package.

Power Crystal

It was the cool, extra shiny design of the Power Crystal that intrigued me in the PR images, but it ‘s the feather weight of the whole package that makes the Power Crystal a winner in my book. In short: you don ‘t feel this thing in your hand, and I have a hard time believing there really is a 2000mAh battery jammed inside this plastic casing (it really is in there, though).

The Power Crystal ‘s plastic shell is a real fingerprint magnet, but the black sample I received for review manages to hide most of my grubby prints. There ‘s a lanyard loop on the top-right, a button to light the four LEDs that indicate current battery life, and two ports.

The Power Crystal charges itself via mini USB (there is a cable included so you can charge from your laptop, but no AC charger), but it charges other devices through a USB output. This is all quite ordinary, but for the fact that the USB port here is actually upside down. This isn ‘t a big deal in terms of usability, but I do find it to be a *very* strange design choice. The cable that comes with the Power Crystal helps hide this fact because it winds and twists so easily, but more fixed cable designs (like the one on the Scosche FlipSync) will require you turn either your iPhone or the Power Crystal over to charge.


I don ‘t believe there ‘s a name for the cable that comes with the Power Crystal, so I ‘ve taken to calling it Mr. Twisty (I made that up just now). Unlike most other portable cables, which are either far too short, or rely on spring-loaded retractable mechanisms, the Twisty is just a wound-up cable, much like the ones you find on wired telephone receivers.

The only confusing portion of this cable design is the way the modular tips work. MiLi gets big User-Friendly points for including mini-USB, micro-USB, iPhone, LG, Samsung G series, Blackberry/HTC/Motorola, and Nokia cable tips with the Power Crystal by default. This is great, since these tips are something you usually have to pay extra for (and order separately), but only some of the cables seem to be sync-capable. I was able to sync a loaner Motorola Dext (Android) with my MacBook using the micro-USB tip, but the 30-pin connector . I tried both the USB ports on my MacBoook, but all I could get was the usual USB trickle charge.


I ‘ve reviewed a fair number of external batteries at this point, and the one big lesson I ‘ve learned is that charging definitely is not a 1:1 operation. So, while the Power Crystal ‘s 2000mAh battery should juice the iPhone 3GS ‘ 1400mAh battery up and still have some charge to spare, the reality is that you should expect just one good charge out of the MiLi Power Crystal (give or take 10%).

I came to this conclusion after running the battery very nearly dry (5-10%) and then leaving the MiLi attached to the iPhone for two hours. The end result was always a fully charged iPhone and then a Power Crystal that was gasping for electricity.

I tested the device on my iPhone 3GS so I can ‘t guarantee iPhone 4 compatibility, but I personally doubt that will be an issue for users who have upgraded.


The Power Crystal provides your iPhone 3GS with one full charge, and is light and small enough that you won ‘t even feel it in your gear bag. MiLi hasn ‘t come up with a radically different product or design (although it is really good looking), but I think the Power Crystal includes enough extras (Mr. Twisty and the modular cable tip gang, as well as a drawstring pouch) to make it well worth a purchase.

The MiLi Power Crystal is available for about $45 from MiLidirect.com.

The Power Crystal was provided by the Max Borges Agency for review on Just Another iPhone Blog. For further information regarding our site’s review policies, please see the “About” page.

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  • Gregory

    Works great with my iPhone 4!

  • A. Nott

    Does not work with my new i-phone 3GS updated with current Apple software. 7 Nov 2010

  • Edward

    Running 4.1 software on my 3GS and the Power Crystal does not charge the iPhone.

  • T

    How do you recharge the Mili crystal?