For the rebuild of the Bruce Gordon I am working on implementing my own hub-generator – USB charger. Why? Well I am not entirely happy with the BM Luxos U headlamp that comes with an integrated USB charger port. The USB connector is integrated into the handle bar light switch and for what I want to do that makes the wiring messy and cluttered. Also I think the handle bar switch adds a level of unnecessary complexity and points of failure. So I am going back to a simpler set up for the light and charger.
Switch between lights and charging instead of trying to do both at once.
A large lithium battery pack charged off the hub will be used to recharge the Garmin 500 off line each day.
I have ordered two of these kits at $8.00 each from Amazon.
Fundamentally this is the same circuit I have been experimenting with except the full wave bridge rectifier is made of discrete 1N4007 diodes instead of a single integrated circuit component. Nice thing is the PC board which alone is worth the price of the kit.
Found the above circuit to add a super-capacitor as a backup to the hub dynamo during stops. I will be using two super caps in series to get the 5v for the USB port. Also looking to add the necessary components to handle the Apple gear.
I have ordered 1N5822 3A Schottky diodes to replace the 1N4007 diodes to reduce the voltage loss across the bridge. Will use a low drop out (LDO) voltage regulator instead of the one that comes with the kit.