I have a 12VAC dynamo I am planning to put on my bike and I want to know how to transfer the electricity generated into a Micro USB cable or USB port. There are devices out there costing upwards of $100 to do this but I want to know if there is a cheaper way for me to construct something like this.


The design I had and device I had originally designed worked, I was just using a faulty USB cable.

  • \$\begingroup\$ easily found on the bay of fleas - have you looked? \$\endgroup\$ – Solar Mike Mar 27 '19 at 15:05
  • \$\begingroup\$ 1st specify Isc and Voc for short and open circuit in your desired speed range. Then max load power \$\endgroup\$ – Tony Stewart EE75 Mar 27 '19 at 15:06
  • \$\begingroup\$ what voltage are you trying to produce? \$\endgroup\$ – jsotola Mar 27 '19 at 20:31

Since you are starting with AC the first thing is to rectify it into DC. A bridge rectifier is good for that. Now that you have DC (albeit lumpy), you will want to add some bulk capacitance (to remove the lumps). Then finally use a DC-DC converter to convert the 17Vdc into 5vdc. WAIT, WHAT? 17Vdc?

The answer is purposely kept high level and general to encourage learning and discovery on your own. Also how 12Vac becomes 17Vdc is an exercise for the student.


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