3 30 watts led lights to run for dusk to dawn

DarkstormNH

Gents I plan on running 3 30 watts led on a dusk to dawn sensor, what would be the minimum setup to support this.
can I run them  on one 12 volts battery 100ah sealed , one 85 watts panel and a 500 watts inverter, small pwm controller
 setup would be in petionville haiti

please advise

BB.

That is going to be quiet a large system (assuming you do not use smaller lights plus, possibly, motion sensors on the larger light). 30 Watts of LED lightning is a lot...

Anyway, here is the basic math--alter to fit your needs.

• Est. 12 hours of lighting per night
  
• 12 hours * 3 lights * 30 Watts per light = 1,080 Watt*Hours per day average (assume 12 or 24 volt DC lamps)
  
• Battery: 1,080 WH per day * 2 days * 1/0.50 max discharge * 1/12 volts = 360 AH @ 12 volts (4x 6 volt @ 200 AH "golf cart" batteries)

Charging--Suggest 5-13% rate of charge, with 10%+ for full time off grid usage:

• 360 AH * 14.5 volts charging * 1/0.77 panel+controller deratings * 0.05 rate of charge = 339 Watt array minimum
  
• 360 AH * 14.5 volts charging * 1/0.77 panel+controller deratings * 0.10 rate of charge = 678 Watt array nominal
  
• 360 AH * 14.5 volts charging * 1/0.77 panel+controller deratings * 0.13 rate of charge = 881 Watt array "cost effective" maximum

Then there is based on loads and hours of sun per day... A fixed array:

http://www.solarelectricityhandbook.com/solar-irradiance.html

Petionville
Average Solar Insolation figures

Measured in kWh/m2/day onto a solar panel set at a 57° angle from vertical:
(Optimal winter settings)

Jan	Feb	Mar	Apr	May	Jun
6.00	5.91	5.58	5.31	5.27	5.97
Jul	Aug	Sep	Oct	Nov	Dec
5.94	5.29	5.23	5.27	5.42	5.74

Now--I would use a 65% to 75% fudge factor for a system that must run 365 days per year and supply needed power (allowing for streaks of less than average weather, etc.)... Your choice:

• 1,080 WH per day * 1/0.61 DC system eff * 1/0.75 continuous usage factor * 1/5.74 hours of sun per day = 411 Watt array "minimum"

So--Somewhere between 411 and 678 Watt array based on above guesses (a bit larger if 12 volt @ 400 AH  battery bank).

Now--With our eyes, we see light as "logarithmic" curve. More or less, a factor of 2 change in light wattage is barely perceptible. A change of a factor of 10 is a "night vs day" difference.

So, if your 3x 90 Watt lamps were 3x 15 Watt lamps--Nobody would know the difference. And make your loads 1/2 as large. And make the solar+battery system 1/2 as expensive to install and maintain.

Other options--Use 1.5 watt lamps on all night, and use 15 Watt lamps with motion detectors to save more energy.

Anyway, a starting point for discussion.

-Bill

mcgivor

Assuming 12 hours on, the total energy used would be 3 × 30 ×12 = 1080 Wh or 90Ah, which would need a battery of, at very least, double the amount of energy used, to prevent discharge below 50%, so a battery of 200Ah would be better suited. It's always best to allow for a day of little production so double that to provide insurance, 400Ah. Inverters use energy themselves, lost as heat, which makes them less than 100% efficient, typically ~85-90%, so this needs to be added to the total load. A more efficient method would be to use 12VDC LED's, as long as the runs are relatively short.

What comes out of the battery needs to be replaced, so using the 1080Wh model with an average 5.5 hours per day, 1080÷ 5.5 = 196 W, but as panels rarely produce their rated output, typically 80%, the result would be approximately 196 × 1.2 = 235W needed. These figures are using optimum year round tilt facing south, with a static array. However as the battery is now 400Ah, the array needs to be large enough to recoup for a lost days production, so a 500W array  would be more realistic, perhaps even slightly larger if there are overcast days regularly.

This is a rough calculation just to provide what approximately is required to avoid dissapointment.

Edit, seems Bill worked his magic and posted whilst I was creating/calculating, thought about deleting but what a waste of my time.

DarkstormNH

mcgivor said:

Assuming 12 hours on, the total energy used would be 3 × 30 ×12 = 1080 Wh or 90Ah, which would need a battery of, at very least, double the amount of energy used, to prevent discharge below 50%, so a battery of 200Ah would be better suited. It's always best to allow for a day of little production so double that to provide insurance, 400Ah. Inverters use energy themselves, lost as heat, which makes them less than 100% efficient, typically ~85-90%, so this needs to be added to the total load. A more efficient method would be to use 12VDC LED's, as long as the runs are relatively short.

What comes out of the battery needs to be replaced, so using the 1080Wh model with an average 5.5 hours per day, 1080÷ 5.5 = 196 W, but as panels rarely produce their rated output, typically 80%, the result would be approximately 196 × 1.2 = 235W needed. These figures are using optimum year round tilt facing south, with a static array. However as the battery is now 400Ah, the array needs to be large enough to recoup for a lost days production, so a 500W array  would be more realistic, perhaps even slightly larger if there are overcast days regularly.

This is a rough calculation just to provide what approximately is required to avoid dissapointment.

Edit, seems Bill worked his magic and posted whilst I was creating/calculating, thought about deleting but what a waste of my time


Gents 

Thank you very much the led's are 30 watts each 5k brightness i think they call that kelvin any ways i will lokk for dc led that can provide the amount of brightness or I will setup the two 315 watts panel a small mppt charge controler and a small inverter

BB.

McGivor---No problem. Different view points of same problem gives more options.

DarkStorm,

There are lots of LED Flood Lights out there that will run at 12 vdc or 24 vdc (higher wattage?).

https://www.amazon.com/dp/B0752GWL17
https://www.amazon.com/STASUN-Security-Equivalent-Waterproof-Floodlight/dp/B076JCGT27

The 5,000 Kelvin is the "color temperature" of the LED. More or less, you will get more light from a 6,000K LED--But the "color" is very blue white and gives very "washed out" colors.

5000 k I like for a flashlight--Still very efficient, but not so sickly white outdoor illumination.

4000 k and below is "warm white". Nice to use around the house. The CRI (color rendering index) is typically higher for warm LEDs.

Here is a link to a (pretty nifty) Chinese flashlight mfg. He has a good example of color temperature vs what it looks like (scroll down a bit):

https://www.aliexpress.com/store/product/Free-Shipping-Convoy-S2-Black-Cree-XML2-U2-1A-AMC7135-3-2-Group-3-5-Mode/330416_1614309086.html

I highly suggest you get one light (or several different brand/models/types) and see what you like.

12 VDC is nice for a smaller system... 24 VDC based lights will be easier to send the power over longer distances.

-Bill

softdown

I'm afraid you have you CRI information backwards BB. The highest CRI's are found with "daylight" bulbs.......generally in the 5200K to 6500K range. I've sold hundreds of such bulbs. With CRI's ranging from 92 to 99 as I recall. 

Lumens also tend to be highest in the yellow and green spectrums found in the common and traditional "cool white" fluorescents. This may have changed over the past decade with so many traditional theories being literally turned upside down. 

I think the traditional fluorescent bulb, used maybe 90% of the time,  had about a 4500K spectrum? Maybe even 4200K. 

Its all personal preference anyway. Warmer bulbs (high in yellow and green) lend a more golden skin color for photography....generally more flattering. In a way.....skillful photography is practicing the art of deception. In a way. 

http://www.westinghouselighting.com/color-temperature.aspx

softdown

As for OP.....I may suggest motion activated lights and hope your pets don't like to "perform under the lights". Also......consider solar lights with the expectation of periodic battery replacement assuming the quality is high enough to outlast the batteries.

BB.

For CRI and filament bulbs--Yes, high CRI goes with Daylight "high temperature" filaments.

For LEDs (and florescent tubes), it is more complicated. The black body radiation is a uniform curve for "hot" objects (surface of sun, hot tungsten filament, etc.).

With LEDs (and florescent), the more accurate CRI (90-100 CRI), they use more phosphors to "add to the spectrum" (usually more expensive, rare earth phosphors). The "typical" 6,000+ Kelvin LED bulbs tend to have a very poor CRI but are very efficient (high Lumens per Watt).

It is not a simple problem:

http://www.cree.com/led-components/media/documents/LED_color_mixing.pdf

-Bill

softdown

Well....much has changed since the reign of the fluorescent bulb then.

I never thought I would live to see the day that people didn't know what gender they were either. 

softdown

It gets pretty mucky once one leaves the fluorescent bulb realm. https://eaglelight.com/led-university-lighting-tutorials/led-color-rendering-index-explained/

I might get a headache if I looked at this too long. Candles and incandescents have a 100 CRI........with 1700K and 2700K colors. This is .... witchcraft.

Examples of Color Temperature and CRI

Light Source	Color Temperature	Color Rendering Index
Candle	1700k	100 CRI
High Pressure Sodium	2100k	25 CRI
Incandescent	2700k	100 CRI
Tungsten Halogen	3200k	95 CRI
Cool White	4200k	62 CRI
Clear Metal Halide	5500k	60 CRI
Natural Sunlight	5000-6000k	100 CRI
Daylight Bulb	6400k	80 CRI

mcgivor

@DarkstormNH

Can you let us know what's the purpose of the lighting, if it's outdoor area lighting, perhaps using stand alone self contained solar powered street lights may be a cost effective way to go, prices vary according to quality, wattage and so forth, but the need for wiring, charge controller, centralized battery, inverter and all associated safety devices are done away with. Just some thoughts 

Anawa

I'm with MCG. What are the specific LED fixtures you have in mind? Is the 30w rating the incandescent equivalent or is that the wattage of the LED? You may be able to meet your lighting needs with a simple 12v set-up that does not require inverters, but first, tell us about what your trying to do. 

FWIW, I'm running 12v MR16 LED "down" lights around three buildings off of fairly inexpensive MPPT charge controllers. They all operate 3 hours after "dusk" and have been for about 8 years or so. The barn has perimeter "wash" lighting from the eave to the ground. And, inside the main bay, there are LED's mounted at the ridge beam that illuminates the floor area below. Understand that I can not read a newspaper in the light, but I can see where I'm walking which was the intent.

just saying
Paul  

DarkstormNH

mcgivor said:

@DarkstormNH

Can you let us know what's the purpose of the lighting, if it's outdoor area lighting, perhaps using stand alone self contained solar powered street lights may be a cost effective way to go, prices vary according to quality, wattage and so forth, but the need for wiring, charge controller, centralized battery, inverter and all associated safety devices are done away with. Just some thoughts 

Thanks for the reply lights are for outdoor in Haiti were electricity is not consistent, base on all the feedback from this group I'm staring to look at solar outdoor lights dusk to dawn , they need to be bright and able to dim down yet still provide some brightness

Thanks

littleharbor2

There are solar LED night lights that have a full time low level lights and motion sensor activated brighter lights. Is this what you are looking for?