Motion Detector Lights are The Rage in Europe


In general the IR motion sensor consumes about 90 uamps (that's micro amperes, 10^-6 amperes) while waiting to be triggered by the IR sensor.

When it triggers, consumption boosts to about 20 ma (milli amperes, 10^-3 amperes) just for the 0.25 seconds it takes to command the light on. Once the light is ON, the sensor itself returns to 90 uamps.

The light itself then consumes power according to the watt specifications of the bulb, be it incandescent (getting rare), CFL (phasing out) or LED (very low consumption/heat). It will remain on consuming that power until it times out. The time out circuit is also down in the uamp range and can be ignored because the light itself is so much more.

Designs differ as to whether or not motion detected while the light is on resets the time out clock and keeps the light on. Most are like this, not all.

In general the number you are asking about is the 90 uamps. That will likely be at 12 Volts (stepped down from house voltage and converted to DC). 12 V X 90 uamps = 108 milliwatts. This is continuous and insignificant vs the light bulb itself. Like so. 108 milliwatts X 24 hours = 0.026 watt hours. A 20 watt light bulb kept off by the sensor for just 10 minutes a day = 1.7 watt hours. If that sensor can keep your light off when unneeded for just 0.108 / 10 = about 30 seconds. If you keep the light off unnecessarily for about 30 seconds per 24 hours, the motion sensor saves power.


I just woke up here in Antalya, Turkey... AND THAT SEEMS GREAT.


What about this? Personally, I despise the light that come from fluorescent Light bulbs, therefore, for me, I would use 100 watt old style bulbs. What is the energy saving strategies? Normally, it appears that fluorescent light bulbs on average worldwide appear to cost 2-5 times more per bulb. The we have the length of time before they stop working, and the variable of the number that break.

It is hard to suss out, but as I understand, the old style incandescent used 4.20 cents per year, and the article does not seem to state how long they are used per day, hour month?

I would easily pay 4.20 to use an Incandescent to read per year, and put he other types in weird locations. Yet, I really have never read by LED lights, used them in a van to read, but they were hopeless with the lights I was using, because the light was not diffused correctly.

Fun stuff, but in the end, I suspect that just walking to the super market 1-3 times per week is radical savings.


4.2 cents per year from an incandescent? Typical power cost is 13 cents/kilowatt hour. That does vary by locale, but that's typical. The Philippines is quite expensive, above 20 cents per KW-Hr.

A 100 Watt light bulb on, say, 8 hours per day is 800 watt hours per day. That's 0.8 kilowatt hours. X 13 cents is 10.4 cents. The 4.2 cents per year number doesn't make much sense. It would have to be mostly off over 90percent of the time.

The incandescent has a filament inside that heats up and glows and eventually, after not much time, just breaks from loss of material and the 60 Hz vibration, not to mention other vibrations.

LEDs and CFLs are more expensive up front, but there is value in lasting a very long time, and burning less electric bill while they do.


I often carry a light bulb in a plastic cup as I travel, they break often, mostly because of vibrations, not really dropping. They are cheaper by far than the others, I am thinking about buying a LED light to carry, but would not be happy when it breaks, or I change from 110-220.


Given how you travel and live, I'd suggest the right answer is an LED flashlight. The batteries are going to last just about as long as they would sitting on a shelf doing nothing. If they are rechargeable, hell, you can figure all this out. If carrying the bulb is to put in a room when you get there, there are little battery powered LED lanterns (as opposed to flashlights) that would light the room as effectively. You're also somewhat soon going to face an availability issue. The US is outlawing incandescent bulbs. The EU and most other places, too. Regardless of the issue of being told what you can buy, demand is crashing and the factories just won't make them anymore. There is a wiki on phase out of incandescent bulbs.

LED bulbs price should fall. Volume and all that. But, the price is what it is for now. Just looked at a lantern. $16. Programmable, can reduce light output as night light or something, as opposed to full power for walking around doing things or dressing. Ya, $16 will buy a lot of bulbs, as long as they are available.


CFLs are not created equal, they come in several different temperatures of light from a yellowish soft white all the way to a bright white which is closer to sunlight.

If you want to see new products meet me in Vegas in January and I will get you into the International Builders Show with me, it is the 20th to the 23rd and is the conference I told you I had scheduled before I could go down to Lagos Atitlan. The first few times I went to took me 3-4 days to walk the entire thing, not because of a walking problem but because there is so much to see. It is a building products disney world.


Owen K, this does sound perfect, an LED reading light. I have a little keychain LED light I sell in my Travel Security Training Kit, and it last for years. It only stops when I go swimming. LOL.

And, I have tried to use them for photography lights, purchased a few in Dollar Tree.

But, these are all spot light, pointed directly at something like a flashlight, they are pointer lights. Have you used one that is battery operated that diffuses enough to light a corner of a room almost like an incandescent light? Then, it need to be small, about the size of an apple, and clip on beds headstands. I can make it clip using a hanger, so the most needed is diffuse, and battery, prefer 2 double aa, because my recharge system is set up.


Sounds right. Lasting for years. Batteries, the alkaline non rechargeable type, die eventually just sitting on a shelf. The usual quote is 7 years shelf life, but reality is probably 5-6 years, because the definition of "dead" varies. Once the voltage drops below a particular level, it doesn't matter if there are still milliampere-hours left at that lower voltage. What matters is whatever you were powering with the battery won't work at that lower voltage. So it's dead in 5-6 yrs on a shelf rather than 7.

Double AA batteries, alkaline (which is most now, non rechargeable), have about 2800 milliampere hours in them. You never get to use all of that 2800 because of the drop in voltage problem just described, but 2600 is a good rule of thumb. That's 2600 mamp-hrs at 1.5 volts or (amps X volts = watts) about 3.9 watt hours. Two of them will usually be in series (not parallel) to get volts up to 3.0, which means it's still 2600 mamp-hrs, but at 3V. And so, 7.8 watt hours.

A generic white LED consumes about 50 milliwatts in operation so leaving it on all day long would consume only 0.050 watts X 24 hrs =
1.2 watt hours. Basically if you leave it on 24/7, then 7 is what you're going to get, 7 days. You aren't going to do that. Congrats on including such a thing in your security kit thing. Any traveler, even one who stays in upscale hotels sometimes when feeling splurgy, should have such a thing in his bag. You can forget it. It WILL work when you need it, and you eventually will.

Amazon has some clipable such things for the bill of a baseball cap for reading. Couple of bucks. I don't think personally in terms of reading with an LED because of Nexus tablets or Kindle or whatever one has. They are backlit, but I have heard people say they need ambient light to make them tolerable.

An interesting tidbit about all this you may like. Typically the Nobel Prize for Physics is given out each year to some academic who wins for some study that is so deep that only people in the field have any idea what it is about. But a few weeks ago, early October, the Nobel Prize for Physics this year was awarded to three Japanese guys who developed the blue/white LED that made these light sources possible at damn near no power consumption. Now THAT was maybe the most deserved prize I have seen.


The constant for Hotels, is missing 1-3 lights. Generally, there is no light above the mirrors, and no reading lights. So, I need just plane lights, not fancy, and not pointers, ambient. I can recharge the 2 aa batteries, I have the setup, I do that daily for my camera. It is the diffusion of light that is a problem I can create a way to clip to bed.

YES 100 percent, they deserve a Nobel Prize, go Japan.


Well, the $16 lantern is diffuse and ambient light. but it sounds like it may not quite be what you want in that it may or may not hang well above the mirror. It would be the light you want, but it sits, it doesn't hang, though you're pretty resourceful and you might figure out how to rig a way to hang it.

Here's the link to Amazon, oops they raised price to $17. Here is also an alternate link for $16.

That will be the diffuse area light you seek, perhaps. Size is, in one dimension, mostly the handle, which you may be able to remove and make it quite small. Almost 1 pound and nearly all of that will be the batteries. Bigger than a light bulb you might carry, but gotta be less fragile.

Re rechargeables, Nickel Metal Hydride have phased out Nickel Cadmium now. They hold about 2700 milliampere hours at 1.2 V or
3.4 watt hours. They die sitting on a shelf or in your backpack unused very fast. A charged up rechargeable loses 1percent of its charge each day just sitting unused. This differs a LOT from the 6 year Alkalines. So rechargeables in your flashlight or lantern are probably not a great idea if you need to reach for it in a semi emergency. If it's been a couple of months, the batteries will be dead and need a recharge. But if you use the lantern often, no problem. You'll know you need to recharge.


Well, fun to experiment, but as long as I can buy incandescent light bulbs, nothing seems obviously a good solution for travelers. One pound,or even 6 oz is a huge amount of weight, compared to a normal light bulb. So in a way, I am trying to fix something that is not presently broken. Plus, everything in a backpack breaks eventually, and when it cannot be replaces in any store, in any country, is is not sustainable gear, just a nice toy until it breaks in Africa.

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