New 30Watt?

[koolmart]

This is my 3rd model. It's a 100VDC Panasonic planetary gear motor, possibly a servo motor. It has two side mounted carbon brushes. The blades are 60cmX5cm wood, attached by L brackets to an aluminum spool. They are not shaped, just angled via the brackets into the wind. It puts out over 30V at about 1Amp. But with a load on or attached to a battery it usually stays at 13V in a moderate wind, about 15mph. So it charges OK. There is a blocking diode. Now I can use an 8Watt fluorescent, but not all night, without deep cycling. My goal is to power a 20Watt flourescent or halogen all night. The battery is a 28Ah car battery, they are fairly cheap. I have some questions and would appreciate anyones help, here goes.

Should the angle of attack be great or slight as I have it set now?

Can I use a solar charge controller to regulate my automotive battery?

What will happen when the charge controller "shuts off" the genny?

Will it burn out the motor or brushes?

If I keep my automotive battery over 80% charge will it last a while?

If I use more batteries in parallel to get more AmpHours and dont deep cycle them is this realistic?

Thank you,

Martin

[troy]

Car batteries are the least preferred method unless you can get them for free.  Even with "shallow" depth of discharge (<20%) you will be lucky to get a year out of them.  They are designed to be discharged 3-5% while starting and then recharged immediately.  Any other use will kill them prematurely.

Golf cart batteries will probably last 5-10 years under the same circumstances, for very little extra money.

If you have a flat piece of wood for blades (ie no twist) then you just shoot for a happy average.  If you set them steeper, it will start easier in low winds but have poor inefficient output as windspeed goes up.  If you have it set for a low angle of attack, it will have difficulty starting in low winds, but will have better output as windspeed goes up.

Of course, the ideal solution is a blade that has twist in it, steep at the root, almost flat at the tips.  That gets you the best of both worlds, good starting in low winds, but good output and efficient as wind speed picks up.

A solar charge controller typically shorts out the solar panels when the battery has had enough charging.  That might work on the windmill (causing it to suddenly stop), or it may damage the mill and/or the charge controller.

Good luck and have fun!

troy

[koolmart]

troy,

Thanks for the help, I think I'm looking for easy start up as my wind speed is low.

It seems to put out Ok at about 180rpm. Maybe max around 300rpm. I would love to get a golf cart battery or any deep cycle battery for that matter but, here in Japan everything, I mean everything is 2X-3X the price. The car battery is very cheap at 18USD. Probably cost 10$ to recycle it though. I can get the cheapest MorningStar charge controller here for 60USD, probably the same after shipping from the States.

Again thanks,

Martin

[ghurd]

Morningstar controllers will not take the voltage.

A 12v morningstar will fry at about 25 volts input.

It is a series controller, so when the battery is full the windmill volts will go to 30v, and fry the controller.

G-

[Roamer195]

A really simple method to prevent battery overcharge is to take the positive lead from the genny and put a capacitor across it to receive the charge. The larger the capacitor the better.

Connect the negative from the cap to battery negative. From the cap positive connect two heavy rectifiers, one going to battery positive and the other remaining free.

Connect the second rectifier in series with an SCR and a resistive load, like a few bulbs or heating elements in parallel.

Decide what the peak charge voltage on your battery should be, then get a zener diode for that voltage and put it between the cap positive and the gate on the SCR.

When the capacitor voltage rises beyond that zener voltage (meaning the battery is charged enough), the zener allows the SCR gate to turn on and stay on as long as the generator is providing enough current. All this excess will discharge through the load that's in series with the SCR.

If the wind dies down and power generation stops, the SCR shuts off. The next time the wind starts up, it will push the battery voltage back up and the SCR will turn on again to protect the battery.

That adds up to 1 big capacitor, 2 diodes, 1 zener, 1 SCR, and 1 resistive load.

[koolmart]

G and Roamer,

Thanks for the help. I have a few more questions. I hooked up another identical genny to the battery. This should double amperage, but not voltage, right?

The battery never overcharges. The incoming voltage always stays at 13V.

The battery often drops from 12.67 to 12.58 after some good gusts, perhaps its already dying.(car batt) Maybe the blocking diode is not hooked up properly.

Its in the positive lead to the battery only. Does it need to be connected to both pos and neg from the gennys and then again to the batt?( the pos of the diode to the pos from the gennys, neg to neg?) sorry about the amatuerish language.

Should I have independent wires from each genny to the battery?

Thanks

Martin

[hvirtane]

Hi,

this is a very good description.

You got any time to make

a schematic drawing of the circuit?

- Hannu

[koolmart]

Sorry, tried to upload the schematic but it wouldnt work.

Anyway I have a 60Volt 5 amp Schottky Rectifier in the positive lead to the battery.

The cathode is pointing to the battery. Perhaps this is why my battery never fully

charges, well maybe thats a good thing?

Is a Schottky rectifier the same as a schottky diode?

Ill try the schematic again,

Thanks,

Martin

[Roamer195]

Here's a link to a simple schematic.

http://us.f2.yahoofs.com/users/41983a96z3ed8d890/bcfc_sr/55cd.jpg?phB9isBB0OZnA76k

[koolmart]

Sorry, couldn't open the link.

What about connecting two gennys of differing amperages?

I've searched the board and web to no avail.

One is producing 30V / 1 Amp, the other 2volts/ 2Amps.

Would amps increase? voltage drop?