[QUESTION:] Small Transformer to increase output to batteries?

[Mastiffman]

 Hey Everyone and Good Afternoon!

 I built a Small Test Wind Turbine from a treadmill motor that has 130vDC and roughly 5700rpms and a set of Raptor Gen 4 Blades with a 64" sweep. it's connected to a 12v 416ahr Batt-Bank.

 We've had around 25mph winds the for the last few days and this mmill actually hit over 12v for a bit yesterday but that only in higher gusts...

 So I was wondering what everyone's thoughts were on possible connecting a small inline DC transformer that would increase the Voltage goignt o the batteries by 50% or more?

 Is something like this even possible to do and most importantly Safely?

 Thanks...
Andrew

[Bruce S]

I'm pretty certain transformers will only stepup/stepdown AC. You can build DC voltage multipliers to get the Voltage up above charging cut-in, but you'll sacrifice in other areas.
Perhaps there's a different area you can improve on?
Lager blades will capture more wind but could cause a slower speed.
64" isn't much of a sweep that's less than a 4 foot blade, maybe this could be improved upon? Perhaps a different set of blades could offer better performance?
You could go with gearing, but even there you have offsets.
Can you give us more of what you've got up there?
Was the mill seeing those 25mph winds?  At those speeds you should be seeing better!

[OperaHouse]

There are boost converters you can buy on ebay that will take 10 0r so volts and boost it up to 14 or so to charge a battery.  Generally these devices need to be modified so they don't turn on till a certain cut in speed is reached.  I wrote a thread a little while back about doing this with solar panels and buck converters.  The process is just the same.  First off you need to load down your mill with some resistors and see what voltage and current give an optimal wattage in the range of 15mph.  Not all bad decisions are able to be corrected by the miricle of electronics. 

[tecker]

Realistic voltage from that unit is around 7 volts tops  . Maybe charge one 6 volt at a time until you find one or two more dc motors and have multiple gensets
 The power norm is 250 to 300 rpm with those blades in good wind .

[Mastiffman]

Thank you for the suggestions.

 In Michigan we experienced some pretty heafty winds comparitively over the last few days becasue of sandy and this Turbine was holding at roughly 5-7volts while hitting as high as 13.2 volts in high gusts! And even produced almost 4amp!? lol

 CRAP I know... But once again this is merely sitting abot 35ft in the air off of my second floor roof. I also have some trees that wil be cut down in the spring if all goes well, to free up some cleaner air. As of right now, it's cleanest blowing from NE, E or SE...

 It was good test situation and really showed me that these blades are definitely decent. BUT, I will need a better motor, which I'm hunting down a Servo motor. I will also need more height. I think that I may be able to get a decent amount of clean air within the right conditions in this area. We'll see.

[Bruce S]

That's pretty good. Do you happen to have any pics of it while Sandy was swinging by your state?
20 watts out of a test unit ain't too shabby 

[Mastiffman]

Thanks. Unfortunately I didn't take any pics. 20 watts is crap though. lol

 But it was interesting to see how steady the voltage was with that kind of wind.