No announcement yet.


  • Filter
  • Time
  • Show
Clear All
new posts


    If the power goes out for any extended period of time, emergency lighting will become very important. While LEDs are sexy they have limitations. Most people are not aware that they are not any where near as efficient as many people hawking them portray. Of the total amount of light produced per watt a DC input compact fluorescent (CFL) delivers much more light and at less cost.

    LEDs are great for focused light applications (flashlights and reading lights) low level illumination, red night vision lights, and for use in places where you don't want the light source failing or where it is very hard to change the bulb. CFLs are better when you need a lot of light over a broad area (e.g. typically room lighting such as the kitchen or living room). Both types should be part of your preps.

    Here is some info and a few of the better links on lights, including comparative info on various LEDs and flashlights, applicable for emergency and off-grid applications that I have found:

    Efficacy and efficiency

    A light can waste power by emitting too much light outside of the visible spectrum. Only visible light is useful for illumination, and some wavelengths are perceived as brighter than others. Taking this into account, luminous efficacy is a ratio of the useful power emitted to the total power and is measured in lumens per watt (lm/W). The maximum efficacy possible is 683 lm/W. Luminous efficiency is luminous efficacy divided by this maximum and so is expressed as a number between 0 and 1 or as a percentage. However, the term luminous efficiency is often used for both quantities.

    When choosing lights for living applications, the Color Rendition Index (CRI) is important. This is a comparative number to natural sunlight, where CRI = 100. Anything over 80 is usually OK, over 85 is good and anything over 90 is very good. You will need a full spectrum light to get to around 95.

    Another thing worth noting is that regular fluorescent lights operating off the 60Hz coming out of the wall usually have a 60Hz flicker that is generally only subconsciously noted. However, it does give some people eye strain and/or headaches. The flicker may be greater when powering the light off some non-sine wave inverters. Most of the new compact fluorescent lights (the ones with a regular Edison screw-in, bulb base) and ALL the 12 or 24 VDC input ones use high frequency switching and there is no flicker.

    Basically if you want a flashlight you want high lumens over a narrow angle for a long throw distance (or to be bright enough to blind an intruder). Some flashlight have focusing rings on the head for adjusting the throw angle from broad to narrow. LEDs are ideal for flashlights and will make the batteries last much longer than using incandescent bulbs. In general a low cost one is not good for much than what any cheap flashlight is good for other than longer operation on the same batteries. See the links below for some comparisons. If you are lighting a living space and want a lot of light use CFLs and get the most lumens per watt for the same wattage. A reading light/lamp is in between.

    The efficiency and lumens per watt of common lighting sources are as follows:

    candle 0.04% / 0.3 Efficiency% / lumen//W

    40 W tungsten incandescent 1.9% / 12.6
    60 W tungsten incandescent 2.1% / 14.5
    100 W tungsten incandescent 2.6% / 17.5
    glass halogen 2.3% / 16
    quartz halogen 3.5% / 24
    tungsten-halogen 2.6% - 3.6% / 18-25
    high-temperature incandescent 5.14% / 35

    13 W twin-tube fluorescent 8.2% / 56.3
    compact fluorescent 6.6%-8.8% / 45-60

    Light-emitting diode
    white LED (low power) 2.2%-6.2% / 15-42 .
    white LED (high power) 3.8%-8.8% / 26-60
    white LED (prototypes) 8.8%-14.7% / 60-100

    Arc lamp
    xenon arc lamp 4.4%-22% / 30-150
    mercury-xenon arc lamp 7.3%-8% 50-55

    Ideal radiators
    deal black-body radiator at 4000 K 7% / 47.5
    ideal black-body radiator at 7000 K 14% / 95
    ideal white light source 36% / 242.5
    monochromatic 556 nm source 100% / 680

    Thus a typical 100 watt bulb for 120 volt systems, with a rated light output of 1750 lumens, has an efficacy of 17.5 lumens per watt, compared to an "ideal" of 242.5 lumens per watt for one type of white light. .

    While the chart makes it look like a high efficiency LED provides about as much light as a CFL you need to understand how light is measured. If a light source emits one candela of luminous intensity into a solid angle of one steradian ( the total luminous flux emitted into that solid angle is one lumen. There are about 12.6 steradians in a sphere. If the light source emitted 1 lumen uniformly in all directions it thus provides 12.6 times more light than a source that illuminates 1 lumen over just one steradian. The light from an LED is very directional only illuminating over one to a few steradians while a CFL is nearly omni-directional illuminating most.

    The directional nature of LEDs is the reason why an LED replacement for many incandescent bulbs have many LEDs pointing out in all directions and why lots of LEDs pointing in the same direction (e.g. a LED traffic light) is so bright.

    LIGHTING LINKS (you should find something that lights your interest)


    Don Klipstein's Lighting Info Site!

    NLPIP ? Lighting Research Center

    Luminance Converter

    National Lighting Product Information ? Screwbase CFL Products

    Compact Fluorescent Light Bulb Investment Analysis Worksheet

    LEDs & LED Lights (the definitive source for LED info)

    12VDC Fluorescent lights and LED lights

    12VDC Fluorescent lights

    12V ballasts

    Full Spectrum Lights

    Dimming Fluorescent

    Flashlights (VERY BRIGHT flashlights!)



  • #2

    great post, info & links! way to go.


    • #3
      Re: LIGHTING

      This is the first I have had time to look at this thread. WOW very nice! I have just started to check out some of the links. Super information.
      Thanks Pfwag, its a great help.


      • #4
        Re: LIGHTING --Hand crank powered flurescent light

        If you do a google search for "hand crank fluorescent light" you will find them for sale on the net.



        • #5
          Re: LIGHTING

          I too missed this when it was first posted. Thanks PFWAG for all this useful information, and to Ruth for making the public comment that put it back on the top of the pile where we might notice it again.

          PFWAG, do you have the time to boil this information down to something that would fit into a printable brochure?

          Some of us have been thinking about preparing a series of brochures (in our copious spare time!) available online but designed to be printed on one two-sided 8.5x11 sheet, folded in 3 sections with the front used as a standard-design title page.

          The information would need to be very simple and easy to grasp, designed for the ordinary person who may not be convinced that a pandemic is coming - a person who just wants to take away the quick answer to "so what do I do?" but won't take time to read more or may be intimidated by having to read words like "luminous efficacy."

          I ask because FluTrackers may eventually need to serve the needs of a broader public than it has been geared for in the past.


          • #6
            Re: LIGHTING

            What precautions should I take when using CFLs in my home?
            CFLs are made of glass and can break if dropped or roughly handled. Be careful when removing the bulb from its packaging, installing it, or replacing it. Always screw and unscrew the lamp by its base (not the glass), and never forcefully twist the CFL into a light socket. If a CFL breaks in your home, follow the clean-up recommendations below. Used CFLs should be disposed of properly (see below).

            How should I clean up a broken fluorescent bulb?
            The following steps can be performed by the general public:

            1. Open a window and leave the room for 15 minutes or more.

            2. Carefully scoop up the fragments and powder with stiff paper or cardboard and place them in a sealed plastic bag.
            • Use disposable rubber gloves, if available (i.e., do not use bare hands). Wipe the area clean with damp paper towels or disposable wet wipes and place them in the plastic bag.
            • Do not use a vacuum or broom to clean up the broken bulb on hard surfaces.
            3. Place all cleanup materials in a second sealed plastic bag.
            • Place the first bag in a second sealed plastic bag and put it in the outdoor trash container or in another outdoor protected area for the next normal trash disposal.
            • Note: some states prohibit such trash disposal and require that broken and unbroken lamps be taken to a local recycling center.
            • Wash your hands after disposing of the bag.
            4. If a fluorescent bulb breaks on a rug or carpet:
            • First, remove all materials you can without using a vacuum cleaner, following the steps above. Sticky tape (such as duct tape) can be used to pick up small pieces and powder.
            • If vacuuming is needed after all visible materials are removed, vacuum the area where the bulb was broken, remove the vacuum bag (or empty and wipe the canister) and put the bag or vacuum debris in two sealed plastic bags in the outdoor trash or protected outdoor location for normal disposal.
            "In the beginning of change, the patriot is a scarce man (or woman, and brave, and hated and scorned. When his cause succeeds, the timid join him, for it then costs nothing to be a patriot."- Mark TwainReason obeys itself; and ignorance submits to whatever is dictated to it. -Thomas Paine


            • #7
              Re: LIGHTING

              This post concerns kerosene lamps for lighting. They have to be used with care but do offer a way of light.
              I have 2 kerosene lamps that are close two a hundred years old. Both
              still work like brand new ones. I think we have about 10 lamps total. The others are much newer. All of these lamps use cotton wicks. The wicks vary in widths and lengths. Wicks come in widths from 1/2 inch to 1 inch. There are probably wicks that are bigger and smaller but these are the most common sizes. The lamp needs the proper width to burn effienciently. If the wick is too small, it may smoke too much. If the wick is too wide, it will not fit in the wick holder. The wicks length is important. The wick needs to touch the bottom of the fuel. If the wick doesn't touch the bottom of the fuel, the lamp may go out prematurely.
              The actual height of the wick above the burner is important. When the wick is high, you have a high flame and excessive smoke. If the wick is too low,
              it may cause the lamp to go out. You can play around with a lamp and see what results for this are. Smoke causes soot. The creation of soot on the lamp globe will decrease the light output.
              If the wick becomes charred or burned, extinguish the lamp and allow it to cool completely. Trim off the damage portion and readjust the wick. To trim the wick, use sharp scissors. Flat wicks are the most common. These wicks can be trimmed for different effects.
              For a peaked flame, trim the wick to a point. The flame should not exceed ? inch in height while burning. A crowned flame can be achieved by rounding off the top of the wick with the scissors. The flame should not exceed ? inch in height. For a double flame, trim the wick to two points. The flame should not exceed ? inch in height while burning.

              This site has good examples of wicks.

              Same site with examples of lamp burners.

              Choosing the correct wick size for your kerosene burner

              Examples of lamps burning with differently trimmed wicks.

              If you burn kerosene, burn only #1 kerosene. Use clean kerosene. Kerosene
              is rated by how much sulfur it has in it.
              At one time, I expected kerosene prices to follow gas prices. NOT!!!
              Right now, regular unleaded gas is about $2.15/gallon. #1 kerosene is about $3.50/gallon. Lamp oil is a good bit higher than kerosene, probably as much as
              double. Lamp oil here is usually sold by the quart or half gallon.

              If anyone is planning on using this kind of lamp, I hope this info helps. I looked
              but didn't see anything like this posted. Don't want to be redundant.


              • #8
                Re: LIGHTING

                Thanks tigger2 for the lamp info. We were given a few lamps and I was clueless about how to use them.

                Do you have any estimate of how long (hours) a gallon of kerosene would burn given your suggestion of 3/4" wick height? I suppose the wick's width matters as well. This information would be important in planning how much fuel to stock. Also, does kerosene need a stabilizer such as gasoline does for long term storage?
                "In the beginning of change, the patriot is a scarce man (or woman, and brave, and hated and scorned. When his cause succeeds, the timid join him, for it then costs nothing to be a patriot."- Mark TwainReason obeys itself; and ignorance submits to whatever is dictated to it. -Thomas Paine


                • #9
                  Re: LIGHTING

                  How much kerosene does the Aladdin burn per hour?
                  Typically, the Aladdin burns 3 ounces of kerosene per hour. This is based on a 60 watt light out put, under normal conditions. If the lamp is turned down, the fuel consumption will also be lower. Sometimes high elevations (above 4,000 feet) will increase fuel usage. Most lamps hold approximately 12 hours worth of kerosene.

                  My mother is 85. When she was a little girl, they lived in Alabama, not far from here. Every night she did her homework from school by the light of a kerosene lantern. While not perfect, they do provide light. They are dangerous because of the open flame.
                  You can actually get a more focused light by placing a mirror behind the lantern. This will reflect the light more toward the front. My lanterns hold approx
                  a pint. 12 hours/pint, 8 pints per gallon would give you 96 hours of continuous light. Hope this helps.


                  • #10
                    Re: LIGHTING

                    There's a variety of sources you can use for lighting.
                    Paraffin oil
                    Paraffin oil lamps burn very evenly, and if enclosed, offer some safety versus candles. There's no way to refill them once you run out of paraffin oil other than finding a new source.

                    Oil lamps

                    If you had a source of oil, you could burn this as a lamp. However I suspect that if the pandemic is bad, it would be extremely hard to find a supply. You also would probably want to keep your oil for cooking.


                    Candles burn unevenly without a candle follower. It's light is weak unless there are several. Fire is a real concern especially around children. They can be remade if you have a source of wax i.e. beeswax or some such. The fat from animals can be rendered and you can make candles from that, however usually beeswax was applied as a coating over the rendered animal tallow. It takes a long time to dip candles. It's a autumn activity. If I can find enough animals from hunting or from trading, I may render some tallow. I deliberately bought some books which explain the process, but I have only dipped candles before. It doesn't sound hard, but it does sound labor intensive.

                    Wood torches are almost worthless inside.

                    Kerosene and propane take needed much needed fuel away from cooking and heating during winter. Either may not be available if there's bad shortages. Both produce a lot of heat, which is fine if it's cool in the house but terrible in midsummer.


                    We are using rechargeable batteries with an inverter hooked to a deep cycle battery that is powered by a solar panel. Our flashlights all have LEDs in them. It has a real directed bright light, but it's not a good source of diffuse light to light a room. I suspect that we'll have to adjust our schedules much as the pioneers did: wake with the sun, wind things down at sundown.

                    Fluorescent bulbs

                    I have thought of buying some bulbs. They have mercury in them, and many people are finding a rather high rate of failure with them. They would save on energy, but if there's no electricity, I doubt I'll hook up our inverter setup to power lights but I could do it. It would really run the deep cycle battery down. I have thought of increasing our number of batteries i.e creating a battery bank.

                    I have thought about buying a generator and gasoline, but where would I store all of the gas? It's loud, and I think it wold create a lot of arguments if people wanted to steal it from me. Our furnace is natural gas, but of course the forced air fan runs on electric. I don't plan on using refrigeration if things get bad, and if it's autumn or winter, I can store some things outside to chill them. I have done so, as well as well as chilling things in a submerged stream or lake.

                    I have not seen a good old fashioned way of lighting yet that is practical and sustainable. There must be some alternative ideas that don't produce too much heat, so as to waste energy, and yet can be renewable in some manner like making tallow.


                    • #11
                      Re: LIGHTING


                      A Japanese Scientist Lights Up the World
                      TAG IT:
                      Written by Bob Johnstone
                      FRIDAY, 30 MARCH 2007
                      Thomas Edison?s incandescent bulb may finally be ready for the scrapheap of history

                      The inventor Shuji Nakamura
                      Shuji Nakamura never meant to change the world. All the Japanese scientist wanted was to do some original research, write a few academic papers, make his presence felt. But he ended up revolutionizing the world of light.

                      In 1993, working in isolation at Nichia Chemical, an obscure firm located in the Japanese hinterland, Nakamura invented the bright blue light-emitting diode. It was the first step on the road to a revolutionary new light source that promises to replace the carbon filament bulb patented by Thomas Edison in 1880, which wastes 95 percent of its energy as heat.
                      The role of simple light bulbs as culprits in global warming has assumed increasing importance over the last two to three years, with Australia becoming the first industrialized country to ban the bulb and Cuba and Venezuela phasing them out. The European Union is expected to follow. Eliminating the standard bulb could reduce carbon emissions by as much as 800 million tonnes per year across the world.

                      The trouble is that the incandescent bulb?s most likely replacement, the compact fluorescent lamp, or CFL, has its own drawbacks. Despite the fact that CFLs uses 80 percent less energy and last indefinitely, they are up to eight times more expensive, produce a harsh light that makes human skin look unhealthy and can?t be dimmed. CFLs also contain toxic mercury vapor, which makes disposal difficult.

                      The light-emitting diode, or LED, looks like a better bet. LEDs were invented in 1962 and thirty years later, you could get bright red ones, but not bright blue, or green. This meant that you could not produce white (which is made by adding colors, like the red, green, and blue dots on your TV screen).

                      The story of Shuji Nakamura and how he invented bright blue LEDs, is a classic study of innovation. In addition to Nakamura?s determination, the other key ingredient is that his boss ‑ Nichia?s founder Nobuo Ogawa ? was prepared to bet big on his star researcher?s ability to come up with the goods. For years, Nakamura kept at it, working 12 hours a day, seven days a week. After his first breakthrough, he followed up with a series of other innovations ‑ bright green LEDs, white ones, even brighter blue ones. For the next six years the rest of the world ate his dust.

                      Then in 1999, Nakamura shocked the world again, decamping from Nichia, where he had worked for 20 years, to become a professor at the University of California at Santa Barbara. The breakup was acrimonious: Nichia sued Nakamura for leaking trade secrets (the suit was dismissed). Nakamura counter-sued Nichia claiming unfair compensation on an invention that had netted the company billions of dollars. He was paid just 20,000 yen ? US$180 ? for the patent he filed on his breakthrough invention. The suit was eventually settled for 840 million yen (US$7 million), at that time the largest ever paid by a Japanese company.

                      Nakamura?s invention ‑ High-brightness LEDs ‑ are even more energy efficient than fluorescents. Their light can be blended to produce warm white light which resembles that of incandescent light. LEDs are also robust, non-toxic, and effectively last forever.

                      ... and there was light
                      High-brightness LEDs are already ubiquitous. They are in your cellphone (as backlights for the screen and keypad), your computer (those flashing blue lights so beloved of geeks), and your car (center brake lights and interior illumination). Soon, they will be in your house, initially as a replacement for halogen downlights, then for every other kind of light as well. Builders in California have already begun implementing LED lighting fixtures in their high-end homes.
                      Fourteen years after Nakamura?s initial breakthrough, the market for high-brightness LEDs is growing an annual rate of 17 percent. It is expected to hit US$9 billion in 2010. General illumination is the fastest-growing sector of the market, outpacing mobile applications and other sectors such as electronic billboards and signals.

                      The growing billions of LEDs manufactured annually are mostly made in Asia. Nichia is still the leading manufacturer of high-brightness blue, green, and white LEDs, with a share of over 20 percent. Nichia?s Taiwanese licensee, Epistar, is coming on strong.

                      The success of Taiwanese LED makers like Epistar has not gone unnoticed on China?s mainland. Today, China serves is a massive market for LED products. Witness the huge outdoor display screens and gaudy color-changing buildings like Shanghai?s Oriental Pearl Tower that light up Chinese cityscapes at night.

                      But the Chinese government has also recognized the enormous energy-saving potential of LEDs. It has been estimated that if, over the next ten years, LEDs were to take 40 percent of China?s lighting market, the annual saving would be 100 billion kilowatt hours. That is more than the output of the Three Gorges Dam, the world?s largest electric power generating plant.

                      Beijing has designated light emitting diodes as one of 11 key technologies in the battle to cut demand for electricity. A nationwide program was established in 2003 to develop and commercialize the technology. In addition to the national government, it involves 11 regional governments, 15 national research institutes, and more than 50 commercial firms such as Dalian Lumei Optoelectronics.

                      Chinese manufacturers like Shenzhen Jiawei Industries have discovered that LEDs are a natural match for solar cells. They export millions of stand-alone lights for use in illuminating the gardens of wealthy westerners.

                      This same combination, with the addition of a battery, has profound implications for the one-third of humanity which, having no access to electricity, is forced to depend on kerosene bottle lamps for illumination. Kerosene lamps are smoky, dirty, and easily knocked over, causing horrible burns.

                      LEDs could also bring safe and affordable lighting to hundreds of millions of people in countries like India who live off the electricity grid. Substituting a locally-assembled solar-driven LED system purchased on micro-credit can have truly transformative educational and economic potential . For example, in Nepal and Sri Lanka, where the first trials of such systems are taking place under the auspices of Canada?s Light Up the World foundation.

                      Village children there gain clean light by which to do their homework, parents boost their income through cottage industries. An added benefit is that since, unlike kerosene, LED lighting systems are a non-recurring expense, families have extra cash to spend.

                      Asked which of the consequences of his inventions gives him most satisfaction, Shuji Nakamura replies, ?Helping to prevent the effects of global warming and helping the people of third-world countries by giving them a safe lighting system.?

                      Bob Johnstone was formerly technology correspondent for the Far Eastern Economic Review. His new book, Brilliant! Shuji Nakamura and the Revolution in Lighting Technology, is published by Prometheus in April.


                      • #12
                        Re: LIGHTING

                        I had an opportunity to test some of our supplies when we experienced a major ice storn winter before last. We were lucky because our power was only out for a few days.

                        We used strategically placed candles in heavy holders while we were awake only. They were all extinguished before going to bed. I have some small, battery operated tea light type fake candles that we placed around the house to provide enough light to navigate in the night.
                        We have some battery operated brighter fake candles that provided enough light in the bathrooms for trips in the dark.
                        Solar lights brought inside in the evening provided some light.
                        We really made use of small "headlights" that could be worn and the light pivoted to zone in on a specific area. I made the evening salads in the dark with the help of my battery operated head lamp.

                        While we have a couple of oil lamps and lamp oil, I'm nervous about using them. At the time of the ice storm, our elderly cat was still with us and he loved to knock things over for sport.

                        The inexpensive, battery operated tea lights operate for a long time on a small cell battery. I'm adding more solar lights outside this year that can serve double duty if needed. Keep them outside all day to charge and bring a couple inside at night to provide light. Low cost and no risk.
                        Last edited by prepdeb; May 29, 2009, 01:55 PM. Reason: typos
                        "There's a chance peace will come in your life - please buy one" - Melanie Safka
                        "The greatest way to live with honor in this world is to be what we pretend to be" - Socrates


                        • #13
                          Re: LIGHTING

                          Originally posted by Possibilities View Post
                          In 1993, working in isolation at Nichia Chemical, an obscure firm located in the Japanese hinterland, Nakamura invented the bright blue light-emitting diode. It was the first step on the road to a revolutionary new light source that promises to replace the carbon filament bulb patented by Thomas Edison in 1880, which wastes 95 percent of its energy as heat.
                          12vdc LED's are also available, and require less current than fluorescents, a boon for anyone working with solar power.


                          • #14
                            Re: LIGHTING

                            I'm not saying it's possible, but I'm wondering about something. Often in electronics, LEDs will stay lit on a device long after the device is powered down. In many cases, it's due to the capacitors haven't discharged, and LEDs use very little current, so they continue to stay lit. It seems to me that you could build a capacitor bank to power up low current LEDs. Large capacitors are dangerous in that they offer quite a shock if the end user shorts out a connection across them. On the other and large capacitors are routinely used (or used to be routinely used in televisions).

                            This might be a way to inexpensively use solar to charge up a reserve across a capacitor bank and then discharge it slowly across the LED to dispel light into a room. You'd need a protective box to house the capacitor(s) and a circuit for charging them up, and have a directional housing outside the box to direct the light. It may not be practical nor cheap, but I suspect that it would be both. Any electronic folks out there?


                            • #15
                              Re: LIGHTING

                              Or perhaps a joule thief to power the LEDs?