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After some friendly bullying by Danzo.
I have written a few words (quite a lot actually) on Torches. Have Fun and don’t hesitate to ask a few questions, if something is still a mystery to you after reading this. I will try my best to answer them.
Thanks
Mark
Torches, Batteries and Addiction.
(An enthusiasts guide to more ways to spend your shiny tokens on stuff.)
I am going to try and set out in this article to explain a few the vast array of illumination products available and answer a few of the questions about the technology used in them. I will also cover the all-important batteries that power them.
Incandescent Torches
These are probably the type of product that most people are familiar with. With the classic 2D Maglite the mainstay of many peoples household torch. Incandescent filament bulbs consist of a nickel chrome or tungsten wire contained in the vacuum of a glass envelope. Power flowing through the wire causes it to glow white-hot and emit visible as well an infrared radiation.
Advantages to incandescent torches are cost and availability, just about every supermarket, garage and hardware store will carry them.
Disadvantages are usually in the form of the delicate bulb, which normally has a reasonably short lifespan of a few tens of hours. Dropping them can result in bulb failure.
Don’t think that Incandescent bulbs are old hat though. They can offer very high outputs for their size. High end models such as the Tigerlight and Surefire M6 are some of the most powerful hand held illumination products available.
LED Torches
LED (Light Emitting Diode) torches are the relative new kid on the block. They use semi conducting material to emit light directly. They have several key advantages over incandescent based versions. The main ones are there ability to withstand rough handling with no delicate filament to break. The second is the lifespan. An average LED device run at its rated output could last in excess of 100,000 hours of On time. That’s about 11 years of constant use. So to all intensive purposes you never need to change the LED. Certain custom and tactical versions may be deliberately run over spec for more light output. This may reduce lifespan to only 1000 hours. It’s still pretty fantastic.
LED’s also have some interesting properties. The efficiency of an LED improves when it is run at a lower level of power. So a fading battery will usually power an LED torch for many slowly dimming hours. A bulb based device fades rapidly and stops emitting visible light. Also the light from an LED device appears to be whiter in colour temperature that the equivalent bulb based device which looks yellow.
For the types of LED torches that are readily available two main types of LED’s are used in the majority of products. I know there are more than this and some recent developments in other manufacturers products, but as yet these are still not in as much use as the described products.
The first of these is the Nichia 5mm white. Commonly used in small key ring torches such as the Photon or ARC ‘AAA’ but also used in large arrays in early high output models.
Nichia LED’s are excellent for low output long runtime applications. A typical AAA battery powered single Nichia powered torch will run for 5 or more hours and give a slightly blue tinted light output. Perfect for map reading, reading and navigating dark rooms at night.
The second rather more impressive LED is the Lumileds Luxeon. This is a single very high output device available in several versions. Typical Luxeon III and Luxeon V based torches will give very high output that rivals or even in some cases surpasses the incandescent equivalent. For your average 2D cell bulb based torch a Luxeon III LED based one will usually surpass its performance in all areas.
A quick word on Luxeon Bin Codes.
You may often read people referring to bin code of Luxeon LED’s. Because of the way in which these type of LED’s are manufactured there is some variance in the quality of the produced parts. Because of this Lumileds rate the parts and apply bin codes to them. For a Luxeon III led the bin code may read as follows :-
The Bin code is TWOJ this gives us the following
T=67.2-87.4 Lumens
W= 6050K Colour Temperature Tint White
0= 6050K Colour Temperature Tint White
J= 3.27-3.51 Vf (Forward Voltage)
W=Colour White
So a ‘T’ bin light may give between 67.2-87.4 Lumens of light output. A ‘U’ bin would typically give 87.4-113.6 Lumens of light for the same energy input. So higher bins can be a good thing. But the Colour tint part of the code may also be important to you. It no use having the brightest torch if it’s a yucky green colour. The forward voltage is also important for matching an LED to its power source. To low a forward voltage compared with the battery may result in overdriving the LED and reducing its life span. Although this may be a good way of increasing its output! Think turbo charging your torch. Good heat sinking is important for over driven lights as excess power that is not converted to light ends up as heat. Too much heat is what shortens the LED life or kills it in extreme circumstances.
HID Torches
A HID (High Intensity Discharge) torch commonly uses either metal halide or xenon short-arc lamps. These are capable of incredibly high outputs and efficiency for their size. Most people who have seen the X-Files or many movies will have seen these types of torches in use. They are typically high in cost although lower cost items are appearing on the market all the time. A xenon-arc lamp works by striking an arc between two tungsten electrodes in an evacuated glass envelope filled with xenon gas. This typically requires a high voltage source to strike the arc. The small size of the arc produced allows it to be precisely focussed and this makes it perfect for hand held searchlights such as the aforementioned Peak Beam Systems Maxa Beam or the even more impressive Night Vision Optics Megaray. Typically used by law enforcement or military customers, these are not your average torches for walking the dog. They are typically capable of projecting a beam of light over a mile. Cost may prohibit ownership of such products by individuals but many flashaholics aspire to own one at some point in their collection.
Batteries
Batteries are fundamental to operating our torches and a vast array of types is available. More recently super high capacity rechargeable Lithium Ion varieties are becoming available for general use. These are potentially very dangerous if not handled or understood so a special mention of these will be made below.
Batteries are usually referred to as one of two types. Primary or disposable cells, and Secondary or rechargeable cells. These can be further sub divided in to several chemistry types.
Primary Cell Types (Disposable)
Alkaline
Alkaline or disposable cells are the most common in use today. These are commonly types like Duracell or Energizer usually on sale in your local supermarket. Available in many sizes from ‘AAA’ through ‘AA’, ‘C’ and ‘D’ all in a cylindrical can type format. The typical nominal voltage of these cells is 1.5 volts and they typically drop in voltage in a linear falloff when in use. So you average 2D torch starts bright and falls in brightness as the batteries are depleted.
Lithium
Primary Lithium cells have traditionally been used in high power or long operating duration devices. They typically have a long shelf life of around 10 years which makes them a good choice for standby devices. Lithium cells for torches are commonly either coin cells or watch battery types typically used in key ring or micro torches. Or the much higher capacity CR123 cylindrical cells commonly used in small high output tactical lights. CR123 cells are available in chemists and usually used in camera equipment. They typically very expensive when purchased in this way and I recommend that you seek an online retailer to reduce your running costs. Lithium cells typically have a 3 volt nominal voltage and a reasonably flat discharge curve. This means they can provide high power output for the majority of their capacity.
Secondary cell types (Rechargeable)
Nickel Cadmium and Nickel Metal Hydride
Nickel Cadmium (NiCd) or its replacement Nickel Metal Hydride (NiMh) is typically used in applications to replace alkaline cells. They have a very good cycle life when used correctly of typically over 1000 charge / discharge cycles. Also the lifespan of unused or stored cells can be many years under optimum conditions. Their disadvantage is in the form of self-discharge. They will typically lose capacity over time even when not used. This makes the unsuitable for standby applications or for that emergency torch in your car. But good for regular use applications like a duty light that would be typically charged every day before use. These cells are typically charged on one of the many consumer battery chargers. The charge profile is one of constant current. Smart chargers are available that will terminate the charge when they detect the slight voltage sag (Delta Peak) of a fully charged cell.
Lithium-Ion / Lithium Polymer
Lithium Ion cells or Lithium Polymer cells are typically used in applications requiring the highest possible power density combined with the lowest possible weight. Your mobile phone will usually have lithium technology cell within it. But all this capacity does have some drawbacks, which you should be fully aware of.
Lithium-Ion cells can come in several sizes. Some types are bare cells and some types have inbuilt protection circuitry.
Lithium cells are typically 3.7 Volts nominal per cell but will have a voltage of around 4.2 Volts per cell when straight off the charger. Please note that due to the higher voltage of lithium cells caution needs to be taken when replacing standard CR123 cells. You need to check if you torch is designed to use the higher voltage of the rechargeable lithium cell.
Protection of a lithium cell is very important. If a Lithium cell is over discharged (typically below 2.5 volts) it will damage the cell and possibly make it inoperable or severely reduce its life span. Protection of over charging is more important. If a Lithium cell is overcharged by as little as 1 volt per cell it will cause it to heat up and thermal runaway could eventually cause the cell to expand split and or explode venting flame and poisonous gases.
This is the reason that all commercial electronic devices that use Lithium technology are fitted with PCM (Protection Circuit Module). They really want their devices to be as idiot proof as possible. Even so occasionally reports of mobile phones exploding are not unheard of.
So here we have a dilemma as we can buy bare non-protected lithium cells to use in our torches. Big problem you may think? Well it can be but if used in the correct devices risk can be minimised. Never use unprotected cells in series only on their own or in parallel.
We also have available protected Lithium cells. These are the cells of choice for the casual user. As each cell has its own inbuilt PCM chip to prevent you from over discharge or charge. They simply cut the cells power to the device when the safe limit is reached. This can suddenly leave you in the dark though!
Protected cells are available in the following common sizes. RCR123, 18650 (typically used for laptop power packs) and PILA cells
PILA cells are designed to typically replace 2 or 3 CR123 cells in cells and come in two different diameters. The A diameter is 19mm and the S diameter is 17mm a 168S cell is typically used to replace two CR123 cells in a regulated flashlight. For more on regulation see below.
Lithium cells have a very specific charge profile and must ONLY be charged on a lithium charger. The charge profile is CC-CV (Constant Current – Constant Voltage) which means they are at first charged at a regulated current level of typically 1C (C=Capacity of the cell) So a 1000mAH cell is charged at no more than 1000mA. Then when the safe voltage level is reached the charger holds the voltage stable and lets the charge current reduce until it reaches almost zero. At this point the cell is fully charged.
The best thing to do with Lithium cells is to charge them on a dedicated charger. Usually protected cells are supplied as a complete system. I strongly suggest that you only use unprotected cells if you understand EXACTLY what you are getting into.
Types of torches and torch technology
I am not happy to just describe the type of light source and batteries that torches use so this is a guide to a few common models and their materials, construction and operation.
Modern flashlights are like modern knives; they all do a similar job of letting you see in the dark just as a knife lets you cut things. But just as you would want a particular knife for the job, so it is the same with torches.
You may need to illuminate you key hole at night or read your star chart without ruining your night vision. Likewise you may need to illuminate a potential threat if you are a law enforcement officer. Or possibly inspect a border crossing from a mile away if you work for the military.
For each task so we have a specific torch. Torches have also moved with technology and so we have models that have advanced features and controls that would have been unheard of a few years ago.
Let us discuss regulated and non-regulated lights along with direct drive and other issues.
Non-regulated Torches
Non-regulated torches takes the voltage directly from the batteries to power whatever light source is being used. They have the advantage of being simple and low cost and have no electronics to go wrong. Your common 2D Maglite is a non regulated torch. The disadvantage of a non regulated torch is that the light output will gradually dim as the batteries go flat. So with half flat batteries the torch may only be outputting half as much light.
Regulated Torches
Regulated torches have an electronic circuit that will give constant power and voltage to the light source for as long as possible. It does this usually by multiplying the voltage from the batteries to a higher level (Boost Converter) and delivering the same fixed level of voltage to the light source. Some converters reduce the power from the batteries (Buck) and some do both (Buck/Boost).
Buck/Boost converters are useful when a torch is designed to use several different types of batteries. On Rechargeable the voltage may be lower or higher than with Primary disposable cells. The converter takes care of this.
Obviously we don’t get this extra power for free from the batteries. As the voltage drops the current consumed will increase to give the same power to the torch.
Advantages of this type of torch are that they give constant light output for the vast majority of the battery life. Disadvantages are that a light can suddenly go dim when the flat batteries can no longer sustain the load. Also the regulator itself consumes a certain amount of the batteries power. As this type of product is much more complicated it will be more expensive than a non-regulated version.
Variable power and micro controller based torches
Many torches are now available with variable power. This is a great idea as many applications do not require the full light output. Also reducing the power makes the batteries last so much longer.
Varying the power of a torch can be done in one of several ways. In its most simple form it may simply be a resistor restricting the flow of power to the light source. More complex designs may use regulation as described above or they may use very rapid switching of the LED via PWM (Pulse width Modulation) These features may need a Micro Controller based electronic circuit. This may also provide other useful features such as preset brightness levels, dimming. lockout, strobe, SOS signalling and many more. Some may even have firmware that can be upgraded to add new features to an older design of light.
Tactical Torches
Let us consider that these types of product are aimed at law enforcement officers and military personnel. They usually have one main purpose in mind and that it to use light as an important ally to defeating a potential threat. So in this regard this type of product is usually designed to be tough and reliable to the utmost extremes. In many cases products may be used with firearms, and be subjected to the recoil when a weapon is fired. A typical feature set for a tactical torch may be as follows :-
Tailcap pushbutton operated. So as to allow a reverse grip when used with a firearm.
Typically high power. Over 60 Lumens of light. Some tactical lights are WAY more that this.
Smooth pre focussed beam. You don’t want to mess with focussing a light you just want it to work.
Impact resistant body. Typically made from high quality aluminium finished with type III hard anodise.
Shock Isolated bulb or LED. To stop it from failing when you need it most.
Power Supply. Typically 2 or more CR123 cells for light weight and high power.
Roundup and example models.
Lets start with a few torch models and describe their cost, batteries and features.
Incandescent
2D Maglite. Affordable (£25) well made direct drive standard incandescent bulb. Medium to low light output. Adjustable focus.
Tigerlight. Medium Cost ($140) well made rechargeable standard incandescent bulb. Very high output duty light.
Surefire M6. Expensive ($392), compact. Extremely well made. 6off CR123 powered tactical assault light with 500 lumens output for 20 minutes. Shock isolated bulb assembly. Possibly one of the world’s most powerful torches for its size.
LED
LRI Photon. Tiny cheap ($12) Watch battery powered 5mm Nichia. Great keychain light.
ARC ‘AAA’ Affordable very small ($30) AAA powered 5mm Nichia regulated LED. The perfect keychain light.
Nuwai Quantum III. Affordable small (£25) CR123 powered Luxeon III powered LED torch with semi Regulation. Tailcap switch. Good general use light.
Surefire L1. Expensive small ($110) CR123 powered Luxeon III regulated with two stage high and low tailcap switch. Excellent general use light.
Inova T1. Medium cost ($66) CR123 powered Luxeon III regulated with single stage tailcap switch. Good general use light.
HDS systems EDC Ultimate 60 XR GT. Expensive ($295) CR123 or RCR123 powered Luxeon III regulated with multi mode controls and features. Possibly the best EDC (Every day carry) light ever made. So far.
Night Ops Gladius. Expensive medium sized (£200) 2off CR123 powered Luxeon III based Tactical light. Regulated with multi function tailcap switch with Strobe, Brightness and momentary modes. Perfect duty light. Also good for using around the home!
Surefire U2. Expensive medium sized ($270) 2off CR123 or 1off 18650 or 1off PILA 168A. Regulated Luxeon V based multi level torch. Tailcap clicky switch and 6 level rotary selector, mounted on the LED head. One of the most advanced LED torches made.
HID
Peak Beam Systems Maxa Beam. Expensive ($2000 plus) Xenon short-arc super light. Often seen on the X-Files or films such as Aliens vs. Predator.
Night Vision Optics Megaray. Very Expensive ($7000) Xenon short-arc super light. Possibly the ultimate hand held light. So far! J
LED/Incandescent Combined
Surefire Aviator A2. Expensive ($180) small pocket light. 2off CR123 with regulated high output incandescent and three 5mm led low mode.
Conclusions
Hopefully this article has given you insight into the world of torches and opened your eyes to some of the features and functions available.
As you can see for the examples given above the prices can vary from a few pounds to several thousand. It really depends on your needs and your budget. Often cheaper lights will get the just done in a more than satisfactory way. But just as with knives you are always longing after that ultimate custom folder or the knife as used by Ray Mears to build a 10 man shelter out of matchsticks.
I’ll warn you now that you will never get there. There is always one more light. One more way of illuminating the darkness and bringing wonder to the owner at each operation. One more better, bigger, smaller, brighter, longer running, further throwing, whiter, than the last.
Just remember they are all SHINY and if in doubt two lights is always better than one!
More comprehensive reviews on many of the above lights can be found on my website here: - http://www.cones-stuff.co.uk/
Mark (‘Cones’ on the http://www.britishblades.com Forums)
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