capacitor to keep voltage stable?

[A6D9]

i know a batery will keep the voltage down.  say you are producing 20 volts open circuit and connect it to a 12 volt bat, it will go down to 12 volts and charge it...or somethign along those lines

my question is...i plan on building a small hydro set-up...don;t have detaisl yet..but will be using a grid tie inverter... if the input of the grid tie needs to be 11-14 volts  could I just put a 1 farad 12 volt capacitor to maintaine a voltage within the range of the inverter?

[electronbaby]

why would you grid tie with a 12v source circuit? its much more efficient to increase your source circuit voltage to some value higher that your grid tie inverter output.

Unless maybe you want battery backup.

The answer to your capacitor question is no. The capacitor will make your voltage rise higher based on the amount of ripple you have riding on your DC out of the rectifier. Im sure it will work to some minor extent, but probably not in the realm of where you want to be as far as a sizable power transfer goes.

If you are afraid of batteries, and want to grid tie, then get a grid tie inverter that does not require batteries and wind your hydro alternator for 250 - 300 volts.

[A6D9]

thank you very much.  

I'm not lookign for any real power #'s and i found a 200 watts grid tie inverter.  

but the inputs are in the 12 volt range.  this is why i was thinkign of going this route.  if I can produce a steady 200 watts 24/7.  I could allmost cover my monthly usage.   and this inverter is stackable.  So i could go 2X200 Wattes and sell power back to the grid.  

I'm still not sure how much power my site can produce yet.  move in on oct 10th.  so next summer is my plan.  but I'm trying to envision some sort of way of doing this.

[Ungrounded Lightning Rod]

At the currents and frequencies involved you'd need a humungous capacitor to do a detectable amount of "fill in the valleys" of the ripple.  A very tiny battery will do the same job just fine.

If you're using a backfeed inverter designed for the purpose it will also keep the battery voltage at the right level and use the line as a dump load.  (If you're using one intended for solar it wont, so batteries might not be what you want in that case.  But trying to use a solar panel backfeed inverter with a water genny is problematic other ways.)

[Flux]

Capacitors don't regulate volts in the same way as a battery. The battery voltage clamping ability is related to the electrolytic properties and the emf associated with different materials.

A capacitor will act as an energy store but in this case would be almost impractical. you would still need a charge controller to clamp the voltage and it seems a crazy approach. If you want grid tie without batteries then there are a choice of suitable inverters that can accept the voltage range of small hydro.

Flux