For all those who want to send and receive email while cycling, or use GPS, MP3 players and other electronic devices while rolling down the road, we now have the USB-WERK from Busch & Müller. The USB-WERK is wired to your 6 volt, 3 watt dynamo in parallel with your headlight.
If you don't need a headlight: no problem. Just wire the USB-WERK directly to your hyb dynamo and you're all set. And should you eventually decide to add a headlight, just wire it in parallel with the USB-WERK and you're all set. Switch the headlight OFF and you can charge your device.
An optional extension cable offers the possibility to tap into USB-WERK's energy supply at virtually every spot on the bike. Cable screw connections keep the connections securely water tight. In order to mount the "miniature powerhouse" on the bicycle frame, three differently sized o-rings and cable straps are included.
Some devices, such as many iPhone models, require a constant voltage from the charger. For devices like this, an intermediary or buffer cache battery must be used. The USB-WERK incorporates a cache battery within the housing. There is no need for an additional cache battery.