The Third Rail system provides add-on batteries to provide additional power for your iPhone4 and iPhone 4S. Charging solutions for other devices are currently being worked on, and the Smart Batteries will be compatible across all the Third Rail devices.

The system consists of an attractive sleeve style case for the iPhone that contains a connector on the back allowing an additional battery to be attached, sled style, on the rear. The 1250 mAh lithium ion battery can charge the iPhone4 or new 4S via the case, or it comes with a standard micro-USB connector which you can use to power other devices, including Apple ones via the supplied micro-USB to Apple dock connector.

The battery can be charged via a micro-USB ‘in’ port, and even comes with its own charge indicator via a series of green led lights. You can also stack additional batteries to provide greater charging capacity if you wish. Stacked Smart Batteries will automatically and seamlessly transfer power between batteries, creating as many fully-charged batteries as possible.

The Third Rail System is available from Amazon and Mobile Fun.

  • Third Rail Combo Pack retails at £69.99
  • Slim Case retails at £29.99
  • Smart Battery retails at £49.99

Written By: Rob Gordon

This post was written by Rob Gordon, an IT geek, gadget lover and blogger. Rob has been using the internets since 1994 when the only streaming video was that coffee pot in Cambridge (rip).... Follow Rob on Twitter - @robgordon - about.me/robgordonuk