Review: Third Rail iPhone 4/4S Snap-on Battery Case.

  • November 16, 2011 11:28 am

Just about every battery life extending case/add-on for the iPhone is the same. You either have a case with a battery underneath a thin plastic shell, or, you have a simple battery brick with a port or two with which to plug gadgets in to. And then you have the Third Rail; a case that distances itself from the pack with a unique approach to the typical battery case. Instead of of the battery being on the inside of the case it’s on the outside. Crazy, we know.

The Third Rail is definitely unique. But is this unique design mere marketing gimmick or actually worth the $89.99 price tag? Hop in for the answer…


As far as iPhone cases go, the Third Rail isn’t particularly striking in that it isn’t covered in bold, bright colors or weird physical protrusions. Instead, the designers chose form over function. With that said, we like how the case itself as it’s thin and simple. All of the extra go-go joyce is stored ’round back in a separate add-on so it makes sense, really.

We’re almost ready to write off the case itself as a perfect example of simplicity and basic protection — almost. What we really don’t like is the fact that the sides of the Third Rail case don’t rise above the iPhone’s display, meaning any direct drop on the front will result in a (almost certainly) smashed display. Granted, the primary purpose of the Third Rail case is battery life extension first and everything else second. Add to that the several other battery cases have a similar flush design with the display. Still, it’s not something we’re particularly fond of.

The thing that makes the Third Rail the game changer that it is revolves around the piggyback nature of the battery itself — it pops on and off the back of the case by way of small magnets. This is both good and bad.

  • Good: The overall size of the case can be greatly reduced when the battery is not in use as it’s removable.
  • Bad: If you’re like us, there’s always the possibility you’ll forget the battery. Also, the external nature of the battery means that when in use, it looks like a nasty brick affixed to the back of your phone that’s neither good looking or particularly comfortable to hold.


The battery is rated at 1250 mAh. Said rating slots into the lower end of iPhone battery packs/cases. Mimicking the raw specs are the battery draing/charge results. On average, an almost dead battery (read: 0-5% charge) will go up to ~60% before the Third Rail sputters out. For the added benefit of being able to pop the battery on and off, we find this acceptable.

An added feature that may or may not entice you — The “smart battery” pack, as it’s called, can be plugged in separately from the case and features a microUSB port for plugging in other gadgets.


As far as raw performance goes, we think $89.99 is too much for the 1250 mAh capacity. But toss in the the ability to remove the battery and thereby transform your Third Rail battery case into a more “normal” looking case is impressive to say the least. It’s far easier (and faster) to pop off a battery pack than an entire case, not to mention much less hassle of having to juggle two cases.

If you’re the type that wants the extra freedom an extended case provides, but also have an eye for simplicity, the Third Rail is a solid buy.



  • Protection: 6
  • Performance: 7
  • Value: 6
  • Overall (Average): 6.5



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Gadget lover, smartphone collector, and beer connoisseur. I've been writing about gadgets for three years now and loving every minute of it. Outside of the digital landscape, I enjoy being active outdoors. I'm always up for a good conversation, so feel free to drop me a line!