how to recharge a battery of 12V using a dynamo give 9V?

how to recharge a battery of 12V ?
I am trying to recharge a battery of 12V using a dynamo.Can I use a dynamo of 9V to recharge the battery of 12V? 

Prfesser6 years ago
Hypothetical: You may want to do a search for DC-DC converters. If the 9V DC from the dynamo is run into a DC to DC converter and bumped up to 14 volts, it should be able to charge the 12V battery. HOWEVER, as others have noted, the game may not be worth the candle. If this is just for fun, or for a school project, it may be ok. If you're attempting to work with serious amounts of power, the DC-DC converter would have to be pretty hefty (read: expensive, very expensive).
lemonie6 years ago

If this is a lead-acid battery it's not looking like being worth doing. Far too weedy.

ARJOON6 years ago
yeah u can't steveastrouk is right. and also not a crappy 14v below 100ma. because if are able to reach this voltage it will be to weak in powerd and will take forever to charge. better use bigger motors. search in old photocopiers
No, you need a minimum of 14 V