I am hoping to get a solar flood light... does anyone have one already and do you like it? How long does the light last?
This is going up on a horse shelter like 300ft from the house. And I dont want to run power out there. But, it would be nice to be able to get say 20-30 min of light out there when feeding, or just putting the horses back out after a night of riding.
Anyone?
Thanks
Ken H.
Home Depot sells a fully self contained one with motion detector for about $70 I believe they claim about seven days of average use without sunlight. I have not bought it yet but intend to do so for exactly the same purpose. I am not sure if it comes with any type of on off switch or is strictly motion sensor. If it is motion only I do not think it would be hard to wire a switch to it.
I looked at home depot and all I saw there was the small landscape lighting lights, and I think one small motion sensor type that would be used next to the front door of a house kind of thing.
How much light do you need? Over how large of an area. What would be the smallest incandescent bulb (just for comparison purposes) that would be satisfactory? A fluorescent about 1/4 that watttage should be fine.
If you can't find something you like you can put off the shelf components together prety easily to MAKE a light.
You can buy an RV type fluorescent lamp fixture designed fot a small fluorescent tube to run off of 12VDC and add your own battery and solar electric panel. It would be cheaper to buy off the shelf most likely if you find something you like but making a system isn't THAT pricey. You can use a gellcell battery about the size of a motorcycle battery or small electric start riding mower and a small solar panel. PV panels can be found for about 4-5 $/Watt but typically go for nearly twice that. Batteries are not 100% efficient so on an average basis you need to be able to put in about twice what you intend to take out as regards amp hours.
Careful shopping would give you the components to build a pretty good system for about $100. No motion detector, just a simple switch. If you can get by on a relatively dim light and not run it for hours at a time you could probably build a system for $50-$70, perhaps significantly less if you are a good scrounger.
[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]
"I'm not from your planet, monkey boy!"
Thanks for the response. I am looking into this more and more today. I am leaning more towads LEDs right now. About as efficient as you can get.
A 65watt incandescent bulb would be PLENTY of light. And I would only need like an hour of light from it to be happy.
Funny you should post like you did. I am looking at making my own setup right now. Could be an intersting project to do.
Just trying to figure out how much of a panel I need and what LED bulb cluster to try and get. Then just use a deep cycle battery like what I use for my back up sump pump.
I will keep you updated on what I decide on if you want?
Any and all other opinions are still wanted.
Thanks!
Right about now the Antartic has pretty good solar lighting.
Egon [img]/forums/images/icons/grin.gif[/img] [img]/forums/images/icons/grin.gif[/img]
Did you look in the security light section that is where they are.
Ken, This is the basic circuit for an LED with a on off switch powered by a 12 volt battery which is charged by a solar panel. the CC is a shunt Charge Controller which shorts out the solar panel when the battery voltage reaches the setpoint. It contains a blocking diode so the battery is not drained by that short circuit.
The CC is typically bought by the amps and is selected with more current capacity than the solar panel can produce to give you a safety margin.
LED's <font color="red"> MUST HAVE </font color> a series current limiter (R1) or they will self destruct from overcurrent. You subtract the forward voltage drop of the LED at your operating current from the battery voltage setpoint of the CC and note that value (lets call it Vdif) In Ohm's law I = E/R where I is current in amps, E is electromotive force in Volts, and R is resistance in Ohms.
In the above equation (Ohm's law) I is the operating current of the LED. E is Vdif and we solve for R the value of the series current limiting resistor. A little algebra later and we have:
R = E/I or R = Vdif/I This is in Ohms. You also need to know the power rating the resistor will need. P = IE where P is power, I is amps, and E is volts. So we have P = (LED current) times Vdif or V dif squared divided by R (same answer.) This is the power that will be dissipated in the resistor. For safety you need to oversize the power rating (it does not effect the LED, just makes the resistor's life easier. NOw you know the resistance in Ohms and the Power rating so you can specify a resistor.
You need to look up the INSOLATION (not insulation) for your area and figuer out the equivalent solar hours. The sun may be up for 12 hours at the equinox but due to the geometry of a NON-TRACKING solar panel you might get the equivalent of 5-6 hours or whatever due to your latitude. You need to put in about twice what you intend to take out of the battery in amp-hours. (Lead acid) To run 65 watts equivalent of LED light for an hour isn't much of a challenge. I recommed you spread out your LED's for more even lighting rather than clustered where it will be bright in one place and dim elsewhere.
The ckt shown is a representative example of how to design a solar charged LED lighting system. Your actual design need not be to too much more complicated. Depending on the forward voltage drop of the LED's you should be able to place more than one in series with a limiting resistor but the total forward drop must be enough below the batery voltage to accomodate a lower battery voltage when the system is partly discharged.
There is essentialy no limit to how complicated this project could be made but it is good to consider one of my favorite Einstein quotes, "Everything should be made as simple as possible, but no simpler."
Oh, yeah. Tilt the solar panel the number of degrees in your latitude from the vertical plus about 15 degrees if you don't want to mess with it seasonally. If you want to you can change the tilt a few times a year and increase the charging significantly. Aim more verticaly in sumer and more toward the horizon in winter. A rule of thumb is to maximize the size of the solar panel's shadow at local noon. There are one and two axis automatic tracking mounts for solar panels but your appication is not a good candidate for that sophistication.
The X where the schematic is labeled OOPS means the wire is cut there and should not have been drawn.
[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]
"I'm not from your planet, monkey boy!"
Hey four,
Did you get your solar light working? Just curious.
I am still looking to be sure I get the right size solar panel. They are so expensive, that I want to be sure I get the right one. This is supposed to be partially a toy/hobby, so I have to be sensible on how much I spend.
But, I am pretty sure I will go with a flourscent bulb instead of LED. Just because the LEDs wont give off enough light I dont think.
May even go the direction of normal incandescent and see what happens. My thoughts on this are... think of how long you can leave two 55watt headlights on in your car... an hour or so? With a good battery. So, one would be even less. And then the question just comes down to would two batteries work for me? I think so. But... I think I may go with a smaller solar panel and see what happens, then I can always add on more if I need.
Searching Ebay for some panels.
Thats the latest.
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