Saturday, March 9, 2013

Understanding AAA Flashlights

Introduction


This guide is being created to help people AAA flashlights and what to look for when purchasing one. Since most of the good models aren't sold in brick and mortar stores, it's difficult to make an informed choice if you're not part of the community of flashlight enthusiasts, the so-called "flashaholics."

AAA flashlights, from left: DealXtreme R2, Pelican 1910, Streamlight Microstream, Fenix LD01, Thrunite Ti Firefly, Thrunite Ti, Fenix E01, Sunwayman R01A, Olight I3, Olight I3S
Random sample of AAA flashlights
The AAA form factor is a unique one. These type of lights put out the least amount of light and the batteries have the least amount of capacity. But with recent advances in LED and battery technology, even AAA flashlights pack a punch nowadays, and some of them are even "pocket rockets" when you put an exotic lithium-ion battery in them. Even a normal, modern AAA light with just a plain old alkaline battery in it is several orders of magnitude brighter than the bulky 5 D cell lights that were common even a few years ago.

Just as with any technology, choosing the right flashlight involves understanding not only the features and limitations of modern LED flashlights, but understanding your own needs as well. Most new flashaholics gravitate towards the highest-output, bulkiest lights they can find. But as they learn, most people end up with smaller and smaller lights, at least for everyday carry (EDC) purposes.


LED Emitters


Modern flashlights use LED (Light Emitting Diode) emitters in place of the incandescent light bulbs that old people like me grew up with. These old school flashlights were heavy and had horrible output, not to mention horrible runtime.

LED technology has been around for many years, but only fairly recently have they been suitable to replace the classic incandescent bulbs. They've advanced to the point now where they are now superior for most flashlights, and people who haven't seen AAA flashlights this powerful are always surprised.

Most high end AAA flashlights you will encounter are going to be using a Cree emitter. There are many other manufacturers, and some lights even use cheap Chinese knockoff emitters, but we'll be mostly focusing on Cree emitters for high output lights, and 5mm Nichia emitters for some lower end but indestructible survival type lights, such as the Fenix E01, which is considered literally to be bomb-proof.

Common emitters used in AAA lights:


MakeModelNotes
CreeXP-CBudget emitter with a smaller die and good throw. Has less output than some of its bigger-die cousins. Used in budget lights like the Streamlight Microstream and Pelican 1910.
CreeXP-EOlder emitter with a smaller die and good throw. Has less output than some newer model Crees, but sometimes still used in lights where maximum throw is the main goal.
CreeXP-GUntil recently this was the flagship emitter for most higher end AAA lights.
CreeXP-G2This is the new flagship Cree emitter for AAA flashlights, with higher output and better efficiency than the XP-G. The larger die size loses most of the throw advantages of its predecessor, with the beam pattern more resembling the even larger die XM-L emitter, which is usually used on much bigger lights.  
NichiaGSLow output, horrible purplish tint. Doesn't seem like it would be anyone's first choice, but it's efficient, reliable and nearly indestructible. Perfect for  abusive environments like keychains and as latch ditch backups. 


Clicky or Twisty


There's two basic types of AAA light switches, a button switch or so called "clicky" and the ones where you twist the head, or so called "twisty" lights.

Now, for clickies, there are two types of switches: There's the so called "forward" switch, which is also sometimes called a "tactical" or "momentary on". This type of switch activates the light with just a half-press on the button. It is very useful for shining your light on something without engaging the switch all the way, which also comes with an audible *click* sound.

Reverse clickies are the exact reverse, which means that you have to fully engage the switch to turn on the light, and a half-press will temporarily turn the light off, until the switch is engaged again. This type of switch is usually used in cheaper lights, though reverse switches tend to be ideal for mode switching and they are slightly less bulky than forward switches.

Because of the differences in switch design, forward clicky lights usually have a separate way to change the brightness modes, such as twisting the bezel, or a second switch. Where reverse clicky lights usually use the tail switch itself to also change modes, which usually makes for a simpler design.

Most AAA lights are twisty, because clicky lights are always bigger, and people like the AAA form factor because of how compact twisty lights are. But there's still some great AAA clicky lights out there, like the single mode Streamlight Microstream.

Output


This is where most people start. Output for all flashlights is generally measured in lumens. But lumens are a funny thing, though, because of how our eyes perceive light. We don't see twice the lumens as twice as bright, so sometimes with different outputs and different beam patterns, the amount of light output can seem like a subjective experience.

Most AAA flashlights these days are going to be using a Cree XP-G or the newer XP-G2 emitters, which offer a great balance between output and efficiency.

Running off a common chemistry like Alkaline or Ni-Mh most of these Cree based lights are going to be putting out 50-85 or so lumens. Older model Cree emitters will do less, and the Nichia 5mm type lights will do 10-15 lumens.

Runtime


The main limitation of most of these type of lights isn't output. Since LED technology has outpaced battery technology, the main problem with the AAA lights is run time. This is where the more expensive lights really earn their keep, because of more efficient circuitry.

Most flashlights designs try to balance runtime and output, either with multiple modes or setting a conservative output for single mode lights. Lower modes, coupled with efficient circuitry, can give dramatic increases in run time. Some of the so called "moonlight" modes can do over 100 hours on a common alkaline.

The modern AAA flashlight gives you the user the choice between high output for a short period of time or low output for a long period of time.

Brightness Modes


Having multiple brightness modes lets you the user make the choice between more output with a lower run time (usually 30 minutes to an hour) or lower output with more runtime. Simply put, a lot of light for a short period, or a little light for a long period.

There's a wide variety of mode configurations out there, but for AAA lights, it will usually be low-medium-high or medium-high-low. Some lights have so called "disco modes" such as strobe, SOS and various types of beacons. Some lights also have "moonline" or "firefly" modes, which are sub-lumen, meaning less than 1 lumen. These moonlight modes are only visible with night-adjusted eyes, and are very useful for checking on your sleeping children without waking them up, or a trip to the bathroom when camping.

Hidden Modes


Some flashlights have special modes which aren't normally accessed, but can be activated with a certain input to the flashlight. For example, to access the hidden strobe mode on the Olight I3S, you twist the light on and off 7 times in rapid succession. It may sound like a hassle, but 7 twists is nothing in the grand scheme of things when you are replacing a tire late at night on the side of a dark country road.

The AAA lights don't seem to have as many hidden modes as their larger counterparts, but there are a few out there with innovative user interfaces.

PWM


Some flashlights, especially cheaper ones, use something called Pulse Width Modulation on the lower modes in order to vary the brightness. PWM is a fancy way of saying that the circuitry turns on and off repeatedly to make it appear to our eyes to put out less light. Lower frequency has also been known to give some people (like me) headaches looking at it, and of course there's a potential danger working around machinery, which could appear to be spinning at a different speed when you shine a PWM light on it.

Another downside to PWM is that the circuitry isn't as efficient as constant current champs like the Fenix LD01 or Olight I3S. Because of this, PWM lights are usually not very efficient, and the flashlight's runtime suffers as a result. If a light uses lower frequency PWM, it's more efficient but will be easily detectable by the naked eye, which will see it blinking. If they increase the frequency, it's harder for the eye to detect but the efficiency and run time go way down. For this reason, I personally tend to avoid lights which use PWM, but I understand that most people aren't bothered by it.

Common Battery Chemistry for AAA lights:


ChemistryVoltageDescription
Alkaline1.5Alkaline. Disposable batteries with a generous capacity and long shelf life. As long as you don't expose them to extreme temperatures or temperature shifts, at which point they will leak and ruin your electronics. 
NiCd1.2Nickel Cadmium. The first generation of rechargeables dating back to the 1970's, they suffered from "memory" and low capacity.
Ni-Mh1.2Nickel metal-hydride. Used in modern rechargeables like the Sanyo Eneloop.
L921.5Lithium Primary, with a 10 year shelf life and won't leak like Alkalines.
Li-ion3.7Lithium-ion. The 10440 size Li-ion is the equivalent size of the AAA and works (though not officially) in many off the shelf AAA flashlights. They are not officially supported by most manufacturers. Use at your own risk.These lights tend to have a single mode on/off interface.

Want to know more about batteries? The Battery University is a great place to start.

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