Two Photocells to Control One Luminary

[LifeLongWNYer]

Hi all. I am putting a flag pole on the north side of a building and want the flag light to operate in what is often known as "dusk to dawn" mode. In a couple of other locations I have used one photocell and had problems getting the intended results. If I aimed the photocell to the east, it turned the light off properly in the morning, but the light turned on prematurely in the afternoon. If I aimed the cell to the west, it came on okay in the afternoon/evening, but didn't turn off until late in the morning.

So,.... can I wire two photocells, aiming one in each direction, to give me appropriate light control? I want to illuminate the flag, but don't want to subsidize the power company by allowing the light to stay on when it isn't necessary.

I am guessing that wiring two photocells so that all black wires are connected; all white are together; and all red are together, might work, but wonder about one cell "closing", (turning the light on) when the other is "open" (that one would be off) possibly backfeeding power from the "on" cell, to the "off" cell, and cooking one of them.

I guess I could do this with a couple of relays, but wonder if I can do this without them.

Thanks folks, I appreciate the assistance.



JBP

 

[malibu101]

We had "timing" problems with photocells at work a few years ago.
Solution for us was a timeclock like this- https://www.intermatic.com/en/timer-controls/electronic-controls/et1105c
It can be set for sunset and sunrise, plus it is astronomic so as the sun rise/set times change this takes care of that.
It has a battery for the clock so power outages don't affect it. They have worked well for us.

I am not a shill and am in no way affiliated with Intermatic. Just passing on my experience with a product that solved our similar problem.

 

[dogdog]

You can do it if they share the same hot

 

[Duke74]

For best results a photocell should be facing North that way they are not facing the sunrise or sunset. Maybe you have done this but it’s just a suggestion.

 

[txvwnut]

I have one on my fountain and it faces due south as that's the only direction I could point it and works dusk to dawn. Is there an issue with pointing it either north or south or even straight up.

 

[Yankeefarmer]

If you have a WiFi signal available at a power source for it, just buy a WiFi switch that can be programmed to turn on at sunset and off at sunrise. Leviton Makes devices that don’t require a hub. I’ve been using 4 different ones with great reliability.

 

[Bert_]

Always aim them North. If you can't keep it from being hit with direct sunlight then sometimes I'll put a short piece of hose over it (if you're using a through hole type)

 

[Norcal]

Here is a product to look into.

GPS Timers Home

GPS Timers The Most Reliable And Accurate Electrical Timers On Planet Earth Guaranteed! GPS LightLock GPS Solar Timers GPS Timers Astronomical Timers

www.gpslightlock.com

 

[Stuart in MN]

One more vote for pointing the photocell to the north, that is typical.

 

[driftpin]

Sounds like you're all-set, technically.

A suggestion about your post content: a 'luminary' is George Clooney (or unfortunately, Charlie Manson), a 'luminaire' is a light fixture.

 

[Duke74]

I saw that too but give the guy a break. It could be auto-correct.

 

[Norcal]

Sounds like you're all-set, technically.

A suggestion about your post content: a 'luminary' is George Clooney (or unfortunately, Charlie Manson), a 'luminaire' is a light fixture.

I would use the word “infamous” to describe Manson or his like.

 

[BillK]

but don't want to subsidize the power company by allowing the light to stay on when it isn't necessary.
JBP

If this is really your reason I would think with modern LED lamps you will probably spend more money figuring out the photocells than you will save on electricity

 

[Duke74]

Also keep in mind. There are photocells for lights and there are photocells for LED lights. They are different.

 

[eejack]

As long as both photocells are on the same power source ( ie the same breaker ) you can do what you described but it will not work as you expect. When either device decides the light should come on, it will. So it will still come on prematurely and then turn off late.

I have to go with point it north as the other folks in the thread suggested, as it the simplest method.

 

[driftpin]

Sounds like you're all-set, technically.

A suggestion about your post content: a 'luminary' is George Clooney (or unfortunately, Charlie Manson), a 'luminaire' is a light fixture.

I would use the word “infamous” to describe Manson or his like.

That's true, however I prefer this to yours:

 

[LifeLongWNYer]

Thanks all, I appreciate the input. I think I know how to set it up.

To those who noticed my "luminary" vs: "luminaire" error, I do know the difference, but the auto correct thought it should have the final say. It is a good thing, but for every four things that it fixes for me, it screws up two others.


JBP



.

 

[Duke74]

HA! I called it

 

[rburke65]

I’ve installed hundreds of mercury dusk to Dawn security fixtures....some were 110 volt...some were 117Volt, and some were 120 V. Some were 230V. , and some were 240 volt....but all the photo cells were pointing North.

 

[ROBZ71LM7]

For personal usage if feasible I highly recommend a smart switch if you have wifi. You can set dawn and dusk plus offsets from each (say 5 min before or 5 min after) and it will turn them on and off the correct time each day of the year. ~$13.99 if you have wifi.

 

[LifeLongWNYer]

I was looking for something else tonight and happened on my post from a couple of years ago. I did devise a solution and thought i would document it.

So i installed two photocells, one pointing east and one west. I wired each to control an individual ice cube relay, and then fed the power to the flag pole lights through both relays, in series. So, both photocells have to think it is "dark" before the lights come on, and in the morning, they go off at first light sunrise. Three years on, I find that it works great, no complaints at all. Even on dark, really cloudy days, the neighbors lights are all on, needlessly, and mine aren't.



.

 

[BreeStephany]

As others have suggested, either point the photocell north if you want to use a photocell or you can use a simple astronomical time clock control switch to control the light based upon adjusted time of dusk and dawn.

 

[dave*99]

I have found these to be a great way to control my outdoor and indoor lights. Set them by time, sunrise, sunset etc.

You can add wireless remote switches to effect a 3 way configuration etc. Multiple switches can be ganged to operate on the same schedule etc.

I stopped installing photocells after I started using these.

 

[AffableCurmudgeon]

You all are complicating life. You don't need any photocells or apps or phones. Use one of these switches. Thay have a built-in sunset/sunrise calendar. You can set it up to turn on or off at or up to 2 hours before or after the sunset or sunrise. Plus, you can manually operate them as well.

I use these for the carriage lights on two sides of my house.

https://www.amazon.com/gp/product/B074ZN58SM/?tag=atomicindus08-20

 

[dave*99]

You all are complicating life. You don't need any photocells or apps or phones. Use one of these switches. Thay have a built-in sunset/sunrise calendar. You can set it up to turn on or off at or up to 2 hours before or after the sunset or sunrise. Plus, you can manually operate them as well.

I use these for the carriage lights on two sides of my house.

https://www.amazon.com/gp/product/B074ZN58SM/?tag=atomicindus08-20

I had one of these on my outdoor lights. It works. It does have a battery. Mine used an odd lithium battery. The programming was ok for me, not as easy as the Leviton app. Small buttons, tiny display.

 

[Shiftless]

Get one of those astronomical switches and be done with photocells. Not too easy to program, but once you get it dialed in, you’re good to go. Some models need a neutral.