24V to 12V?

[JohnC]

Hi all, this is my first posting so go easy on me, I'm a newby at this but so I got lots to learn.

I have Hugh's book, 24 2"x1"x1/2" Neo's, 16 awg wire, bridge rectifiers. I'm ready to build.

I would like to know if it would be benificial to build a 24 Volt system, rectify it at the mill to DC then at my trailor that is 100ft away use a 7812 regulator and some caps, converting to 12Volts DC. Everything at my campsite is 12 Volts.

In this configeration would the gen not produce usably power more quickly then if I just built a 12 Volt from the start.

Also I could use a smaller gauge cable for my run. "maybe maybe not?"

THX,

John

[drdongle]

7812 regulators are only good for 1 AMP, I suspect that you will be using more than that.

I recommend that you rectify your turbines out put and then run 24 VDC to the campsites batteries ( 12 volt) and then you won't need regulators at all. The system will "self regulate" to the voltage of the batteries. Run all devices straight from the batteries. a filter cap may not be necessary.

[JohnC]

thanks for the info.

if i build a 24V gen and charge a 12V battery bank, would this not charge in  lower winds all things being equal except for the stators.

THX

John

[Flux]

In theory.  In reality Hugh has already designed the thing for best all round performance and he optimises his designs for low wind.

If you use the 24v design on 12v you way get 2 watts at a lower wind speed but for all other wind speeds the blades will be badly stalled and the general performance will be very poor. Above about 7mph the performance will fall badly below the proper 12v design and you may never see more than  a hundred or so watts.

By using a proven design you can avoid all sorts of trouble but you will come unstuck if you do things not intended in the design.  In reality there is so little power available below 7 mph that it is foolish to modify the design to try to do better.

Flux

[Gary D]

John, Hugh made his plans for simplisity sake. If you make the stator for a 24 volt system, yes you'll start charging at a lower speed. BUT your power curve of the alt. won't match the power availble in the wind. The blades won't get to their design speed (blade stall). So you may possibly gain a few watts in a marginal wind, but you'll lose lots more in just a slightly higher wind. Better to stick with his plans... if you want to experiment with the 24 volt stator later, at least you'll have something to compare it to output wise. In high winds, you would have the chance of extreme stator heating and the resulting catistropic failures... Just a thought here... Gary D.

[JohnC]

THX for the info guys.

I will go for the 12 Volts.

Glad I checked this out before major troubles started.

It's great having expertice at your finger tips.

Cheers,

John

[sinclairbrett]

I would look for a circuit using a switched mode converter linear regulators dump a lot of the wasted products as heat.

the 78HG series is good for 5 amps i would not attach 12 v equipment batteries or anything to a 24v supply just relying on volt drops etc apart from possable over volting of your batts eg around 14V max but possable dammage to other equipment connected as well.

switched mode converters are relativly easy to scratch build especially in step down mode plenty of home brew plans on the net.

You dont even need exotic IC,s to do the work

regards

mark