Hello
Im a newbie for electronics and i need help with a school project.
I am building a small wind generator to charge batteries. The batteries i want to charge are 2 ni-cad 1800 mah 7.2 v. My wind generator produces usaully about 9 volts and 4 amps and i would like to charge both the batteries at the same time but the voltage isnt high enough. so is there something to use to double the voltage and half the amps?
Thanks Tim

 

Set the batteries in parallel. That will create a current divider. Each battery will have 9 volts across it. And if they are exactly identical (which they are not, but we will ignore it for a minute), each battery will get 2 amperes.

 

My wind generator produces usaully about 9 volts and 4 amps ...

At the same time, for 36 watts?
I'm just warning you that voltage is often cited without any load, and current is cited for a short, so no voltage. If that is the case, you'll get far less than 2A into each cell.

I suppose you'd get less than 2A anyway, since you're driving current into 7.2V.

Parallel is the way to go, +1. At worst you may need to isolate them a bit.

 

Have you considered how you will know when to terminate the charge, or how to prevent battery damage from excessive charging current?

 

Is putting the batteries in parallel an option for you?