DIY charging circuit for 12V batteries with a capacity from 4Ah to 20Ah, powered by a hub dynamo or small solar panel. The circuit provides two inputs, one unregulated output and one charging output. Each input can be used with a wind turbine or small solar panel. The generator used by the wind turbine is ideally a hub dynamo. (Like the ones manufactured by Shimano or any other standard bicycle dynamo.)

Small DIY project for a weekend with the kids. Build a wind turbine with a bicycle dynamo. Cheap possibility to generate electricity.

Build in features of the circuit:

• two inputs
• voltage doubler (Delon)
• robust design
• trickle charging
• overload protection
• overvoltage protection
• fixed 13.7V output with max 1.5A current provided by charging IC
• unregulated output
• jumper configuration for one or two voltage sources in parallel

Bill of Material (BOM) with part numbers is included. All necessary parts can be ordered by Digi-Key or Mouser or Conrad.

This charging circuit is for garden shed usage or similar environments. With a wind turbine (or any other generator driven construction like a water wheel) it is possible to charge a lead-acid battery and provide energy for 12V devices. Enough energy for light and QRP amateur radio operation.

Both inputs are connected to a voltage doubler (Delon Circuit) to convert the input voltage to an ideal level for the battery charger IC. The dynamo output voltage is transformed to 15~17V and the battery charger PB137 manages the charging of the lead acid battery. If the battery is fully charged, the circuit automatically changes to trickle charging and keeps the battery charged.

The build of this circuit is easy for beginners and all electronic components are standard components available in any electronics store. The circuit is described and shown in the manual, therefore easy to repair if something goes wrong.

ATTENTION: This is only the PCB. No electronic components, hub dynamo, solar panel, battery or any other parts are included.