Dahon, a company known for making folding and collapsible commuter bikes, has developed a suitable add-on for just about any type of bike. The BioLogic FreeCharge takes energy generated by your bike’s tires and uses it to charge up your iPhone / GPS / MP3 player via USB.
The FreeCharge stores electricity generated by a standard wheel hub dynamo into a small rechargeable battery. the battery then doles out juice for your power-hungry gadget regardless of what speed you’re going. Hooked directly to the dynamo you would risk power surges that could damage your precious device.
While most casual bike rides won’t generate enough juice to fully charge anything, you can at least pack along your mp3 player without having to worry about it dying before you’ve gotten where you’re going. Long-distance riders should take special note of this accessory as traveling far enough outside of normal coverage areas can increase cell phone battery drain significantly. When that emergency finally rears its head will you be able to use your phone? The FreeCharge should be available for order in 6 months at $99.