diode to batteries

[guruji]

Sir I did a voltage doubler to my small windmill.Do I have to add another diode to the batteries?Any help?

Thanks


moved to a more suitable section.

Editor.

[asheets]

Need a few more details... like what is the original output of the generator, does it use or need a half-wave or a full-wave bridge before the voltage doubler, what is the design of the doubler, etc...

I'd be willing to bet that if you are using a voltage doubler, then your original output is DC, and that you are using a half-wave bridge (simple diode) to keep the battery from backfeeding to the gen, and that diode is between the gen and the doubler.  I would be willing to bet that you probably don't need another one after the doubler.

[Seaspray0]

A simple one phase voltage doubler consists of two diodes and two capacitors.  They are aranged in a similar "full bridge" fashion but with capacitors on one side and diodes on the other.  Peak current through the diodes will be double (recharge the capacitors and supply the load) as well as the ripple doubling for an unregulated system (do not expect your power output to double, as the current you can push will be less than half at this almost "doubled" voltage before the ripple becomes excessive).  The capacitors will need to be pretty hefty since they will have to take half the voltage load and be able to supply your current needs.  Voltage doublers are not praticle for power applications (a transformer is better suited).  Unless you have capacitors that "leak" DC current severely, you should not need another diode between the doubler and the battery bank.  A simple test... charge a capacitor up and then disconnect it.  How long does it take to discharge on it's own?  That will give you an indication of how much leakage it has.  Note:  leaving a multimeter attached can drain it and give you wrong results.

I always wondered if those electrical engineering courses would come in handy.

[hvirtane]

...Voltage doublers are not practical for power applications...

What is the current practical limit? How big capacitors do you need for 1 kW power 45 V? The costs of the capacitors?

- Hannu

[guruji]

Thanks guys for response;hvirtane it's a small genny from a vcr head.With doubler it's giving out 12v in strong winds and about 20ma.

I'm trying to charge 2 AA batteries.This is an expermental project.

Ok thanks again.