I am making a pedal charger for a 12v 3 ah battery using a ceiling fan generator making over 150vac. I assume current would be improved if a transformer limits the voltage? If so, I need a source for a 220vac to 18vac transformer. Mouser does not seem to stock this. Is there a salvageable alternative?

 

Sounds like you need a transformer with a step down ratio of 150/18 or about 8. Maybe a 16 VAC doorbell transformer would work (if you live in the US). 24 VAC transformers are fairly common. But you don't give a current rating.

If you state both the current needed and an allowed voltage range, you might be able to find a member who has such a transformer in their junk box.

 

Thank you for the advise. I am trying to charge a 12v 3ah motorcycle battery. Max output I believe should be 1 amp dc?