HarveyH42

Getting ready to put together another wind powered yard light, but this time I want to add batteries and a microcontroller (fading RGB LED). I'm not planning on switching the LEDs off during the day, but still a little concerned about over charging the batteries. Haven't really seen anything simple or small scale. Planning on 3 AA NiMh batteries (3.6 volts). The whole mess with be mounted on the vane, and rotate freely.

Any ideas? Guess it's not too important, and could be added later. Worst thing could happen would be battery-juice leaking out...

kchriste

NICAD batteries would simplify the charging circuit as they don't mind as much being overcharged at a low rate (C/16) as NIMH would. There is no "simple" solution to this if you want to get the max life out of them. One simple method would be to put a shunt regulator that doesn't allow the voltage to rise above apx 1.55V per cell (4.65v total).

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Hero999

Since the day lasts for 12 hours it's unlikely it'll become heavilly overcharged.

Even NiMH cells can tollerate some overcharging and they have a higher capacity than Nicad so they're probably the most suitable.

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ericgibbs

Hi Hero,
Its 'wind powered'!

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HarveyH42

Guess it's one of those projects to just build, and fix the details later. I just don't know what to expect. Hero, this is a wind powered generator, it could charge more then 12 hours in a day (doubtful), but I have no idea how much voltage/current the stepper will put out, at what wind speed. It's 5v/200mA rated. I've got one going in the backyard, but just shoved LEDs into the connector. The white is bright and fairly constant in a good breeze. We go through some periods of very strong winds.

I'll need to come up with a design that will be easy to fit a PCB or even more batteries later if needed. Wanted to keep it small a streamlined, maybe the next one...

ericgibbs

hi,
I would use the same method a 'kchriste' suggests, a shunt regulator, you could make the shunt dump load an additional light,
perhaps a low voltage filament or power led.

Whats the blade size and configuration of the present wind gen?

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Bill's: www.blueroomelectronics.com/

HarveyH42

It's just a propeller of a toy airplane shoved onto the shaft of the first motor I could find that would fit snuggly over. Cable ties hold it onto a plastic rod. Cut a piece of scrap metal into a tail vane. Found the balance point on the plastic rod, drilled a small hole part way through. I'll post a picture tomorrow, won't get a descent picture in the afternoon sun. Surprised it's lasted the summer, kind of why I want to build another one, but with batteries.

HarveyH42

Remembered to snap a quick picture. Think the propeller is about 6 inches.

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Nigel Goodwin

I'm pleased to see you have a really attractive skyline!

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HarveyH42

Wasn't so bad before the concrete pole they put in after some bad huricanes on year. Not sure why they left the wood pole...

audioguru

My neighbourhood has buried wires. Electricity, telephone and cable TV.
Yours looks like the pic of the millions of wires above a street in India.

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Nigel Goodwin

Same in the UK, there are a certain amount of overhead wires, but really very few.

Or in North America?, going by what you see on the TV.

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audioguru

I think old cities have many overhead wires because in the olden days low cost was much more important than appearance. Then they left it like that.

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kchriste

When they replaced the power poles on my street, the old pole was left to hold the remaining wires because the Electric Co only moved their own wires over. It took about 6 months for the rest of them (Telephone & Cable Co) to move theirs over. Then another 6 months for the Electric Co to come back and extract the old poles.

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HarveyH42

It's been a couple of years now...

Yeah, this is the old, 'Historic' part of town, maybe 10 or so buidings from what I can tell. They tried to get it designated as a 'Historic District' a few years ago, to get federal funding for something. My house was built in 1946, and nothing special about it, was included. Fortunately, the proposal was shot down, as it would have put some serious restriction on repairs and improvements. I would have had to keep the house and property period correct.

Anyway, the pole(s) are on the back alley corner of the property. The picture makes it look worse then it really is. The down buildings blockout any sort of 'view' anyway. Florida is mostly flat, so not much to look at anyway.