Timer for solar LED dusk/dawn light

I needed a solar recharged, LED light that came on at night. I purchased a small LED light (rather bright with 6 LEDs) that has a solar cell, photo eye and 3 AA size rechargeable batteries. Made to clip on the patio umbrella, it is ssmall and light. The solar cell and photo eye are on one piece. The LEDs, batteries and circuts are on another piece. the two pieces are joined by a wire and are hinged together, allowing the unit to clip on the edge of the umbrella. I plan on removing the hinge and extending the wire to allow a two foot separation. I need to add a timer to this. Something that will turn off the light about 4 to 5 hours after it comes on. I assume it will be something that starts when the LEDs are powered up. Though I guess it may be something that is also triggered by an additional photoeye. Or maybe someone has a better idea? thanks

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Wait till the battery goes flat they turn themselves off then. The ones I have last about 6 hours. Why do you need to turn them off after 4 hours? Pat. Pending
jnlvngstn (author)  Patrick Pending9 years ago
It's the winter night light for a chicken coop. Very suprisingly, the light does not burn out during the course of the night. It does get kind of dim after 7 or 8 hours. Even more so when it is in the freezer (cold). Yes, I could likely just let the light burn out each night, but I'm challenged to make this work 'properly'. That is to add 4 to 5 hours of light to the chickens day. Why? Because it keeps them laying eggs throughout the winter. They normally slow down with the shorter days of winter, here in the northern climates. thanks
Good project solar chickens! I like it. I'll be back, I'm thinking...
OK, I thunked. Assuming you have no mains power to the chicken coop then you would probably need to either: -get/make a timer circuit that worked off whatever voltage you have available from the solar charger. -Use a battery(self contained) operated timer or alarm clock (would require modification) to turn off the light. -Increase the drain on the batteries by adding additional LED's so that the battery doesn't last as long. -Cover up part of the solar cell so that the battery doesn't charge up as much (this is by far the easiest method). Hope this helps, Pat. Pending
. We have a lot of chicken houses in my area and I did some electrical maintenance on one of an acquaintance's houses. We got to talking about raising chickens and, IIRC, he said that the photoperiod timers had to be pretty accurate ("within a minute or so," let's see, that's better than 0.1%) to obtain optimum growth. I would assume the same is true for egg laying. This leads me to believe that depending on battery charge as a timer is not an ideal solution. . Since it seems that the batteries have plenty of reserve power, I'd go with Pat's first suggestion and try to find a timer/switch that consumes as little power as possible. I'd measure the voltage after 5-6 hrs of being on, use that as my design voltage for the timer, and add a regulator for the timer supply.
After reading the reply of NachoMahma I had a quick "google" to learn some chicken science. This is the first link I came across Proper Light Management for your Home Laying Flock. This PDF document suggests it needs to come on before dawn and have the right intensity and colour otherwise it won't stimulate the hens to lay eggs. So, unfortunately, I don't think the LED idea is going to work.

I would like to throw in a witty remark about battery hens, but it's eluding me at the moment.

Cheers,

Pat. Pending
jnlvngstn (author)  Patrick Pending9 years ago
Thanks for all the thought that has gone into the replies. I've done some research into chickens, both reading and asking. With that I've come to see that there are some that just grow their backyard chickens and some that make it a science or are obsessive/compulsive about them. The people I know that use lights, just use a regular light bulb. I've read of using a red light, to stimulate egg laying while helping to prevent pecking. I can understand that the unnatural white of a led may not stimulate egg laying, but I'm willing to give it a try. Maybe I'll change out two whites to a red and blue. But I've got to get it working before any of that becomes an issue. Asto the light coming on in the morning rather than going off suddenly at night. Sounds reasonable. Suddenly off is pretty unnatural, though I doubt my three chickens will crowd into the corner and suffocate. Having it come on before dawn might even make it easier. The photoeye will power up the timer, which will be placed just before the leds in the circut. The timer can be for a length of time or a time of day, to turn allow power to go to the leds. Then when daylight comes (hear the music in the background, 'and i wanna go home') the photo eye will shut the circut down. Oh, wait, if the timer is set to time of day, then it will need to remain powered on. hmmm Any suggestions? Thanks again
. Not sure how much power it takes to run a timer, but I'd try running it off the batteries.
uguy9 years ago
If the led lasts 8 or so hours, it may be a higher mAH rating than you need. Check around and look for a nicad cell about half the mAH rating of the battery now in the unit.