It is rather obvious that most people do need to have a flashlight of some sort at hand. But the needs and requirements are quite different for each class of users and therefore the desirable characteristics will vary accordingly.
You may want a tiny little lamp to keep on your bedside table that you would just use to go to the bathroom without awaking your partner.
You need a slightly bigger torch for use at home in case of a power outage.
These kinds of flashlights can be purchased from any nearby stores or supermarkets. They are easy to find and cheap, but how long they would last is certainly a concern to be addressed. You’ll notice that they are not subject to much strain therefore they don’t need to be very sturdy.
For heavier uses, you will need a more professional tool. Many user profiles can be identified such as (non-exhaustive list):
All of these users will need, to some extent, a flashlight that we call tactical. This paper is aimed at helping every potential user to choose the best tactical flashlight for oneâ€™s own purpose.
The first step is to define the material of which the case of the flashlight should be made. In this market, you will find bodies made of metal or plastic. Furthermore, there may be a coating adapted to the material intended to enhance the quality or bring additional benefits.
It is true that the chemical industry today is able to produce plastics with very good mechanical properties. However, for our purpose, it is clear that the best choice is aluminum. This material has more useful properties than the best plastic product. Aluminum is light weight, non-magnetic, corrosion resistant and a good electrical conductor. Therefore, we can summarize as follows:
Although offering a natural strong mechanical resistance, aluminum has a rather soft surface. In order to prevent scratches and bumps, it is advisable to harden the surface. This is achieved by a process called anodizing. The process consists in immersing the aluminum part into an acid electrolyte and running a current through it. This electrolytic process produces a thin coat of aluminum oxide. The anodic layer is non-conductive. The layer is somewhat porous, depending on its thickness. The corrosion-resistant property is improved by an additional process of sealing. Cooling the acid solution to the freezing point of water produces a much thicker coating that penetrates deeper into the aluminum.
Various types of anodizing processes are known which produce the following results:
Now you know what your best tactical flashlight should look like from the outside. Let’s then have a look at the inside. To begin with, we need a power source. There is a multi-fold choice to make on this matter.
First of all, we have to compare alkaline versus lithium batteries and, secondly, disposable versus rechargeable batteries. We will then look in more details into the selected types.
Lithium batteries last a lot longer than alkaline ones before the energy load is depleted. The ratio is somewhere between four and seven times longer, depending on the particular application. They can also output a higher voltage for a longer period of time which is very useful for many devices. More voltage and more time means more energy stored in lithium cells.
On another hand, lithium battery units are more expensive than alkaline ones. However, the extra cost, if you can afford it, is overcome by the better efficiency so that, on the long run, lithium batteries are more effective than alkaline units.
Finally, it is noteworthy to say that lithium cells weigh about 1/3 less than their alkaline equivalent and they are not prone to leakage of chemical corrosive products that could damage your best tactical flashlight.
With the above data, you have decided that you want lithium batteries. We will now discuss about the most renowned battery types, both disposable and rechargeable.
In the first instance, the two types of cells do not have the same chemical content. Disposable cells are Lithium whereas rechargeable cells are Lithium-Ion.
Most of the best tactical flashlights now are CR123A 3V lithium battery powered. The CR123A battery outputs 3.0V as opposed to 1.5V in an AA alkaline battery. CR123A are small and lightweight. Lithium batteries withstand a wide range of temperature -40F to 140F (-40Â°C to 60Â°C). This cell has a shelf-life of 10 years; this allows them to be easily stored without charge drain. Self-discharge is less than 2% after 1 year of storage at + 20Â°C.
An alternative to the CR123A is the 18500 Li-Ion rechargeable batteries. If a tactical flashlight uses two CR123As it will most likely work with 18650 Lithium-ion batteries (you should consult your flashlightâ€™s manual to confirm compatibility). These cells are industrial batteries with extremely high energy density 3.7V to 4.2V, commonly used in laptop batteries.
18650 Li-Ion cells can be found fitted with Protective Circuit Board (PCB); they are called Protected 18650s. A protected cell will shut down the cell if the current demand exceeds safe levels. It will also be protected from overcharge, therefore you can safely leave the flashlight in the charger cradle at all times when not in use.
As stated above, these cells are rechargeable. Many manufacturers have a â€œcleverâ€? charger in their accessory listing. This protects your battery from overcharge and stops changing when the battery is full.
This battery is the same size as the CR123A but it is rechargeable. RCR123A is sometimes also called 16340. It has a higher voltage (3.2V) but a lower capacity than primary CR123As. It is advisable to get protected type only and to use it with a â€œcleverâ€? charger.
If a flashlight uses two RCR123aâ€˜s (or CR123a’s) in most cases it will be able to run with one 18650. It is advisable to use 18650 instead of RCR123aâ€™s because of higher energy density. I likeÂ 18650′s because they usually are better priced per amount of power they produce.
Primary (disposable) batteries
Less expensive at purchase
Ready to use out of the box
Re-usable many times
Single use, need repeated purchase
Need spare parts storage
Must be charged before use
Risk of overcharging (if not protected
or used with a "clever" charger)
It’s time now to take a step into modernity. In recent times, LED (Light-Emitting Diode) technology has grown as a dependable, powerful and valuable light source. It now outperforms by far other technologies such as the vintage incandescent bulb but also more recent devices such as halogen or xenon devices. However, LED components are still rather expensive but prices are dropping sharply, thus making them more and more attractive and this trend is going to last.
One of the most noteworthy features is that LEDs lack a heated filament and a glass bulb. This means that they are much more impact and shock resistant than bulb type devices.
Another very interesting feature for your best tactical flashlight is its lifetime. Most LEDs today exhibit lifespan of 50,000 hours or more, some high end ones can even go as high as thousands of years.
LED devices are the most efficient as regards the ratio light output/energy consumption. With the constant increase in light power out of a single chip, this means highest light output and longest run times. This characteristic makes LED chips ideally suited for best tactical flashlight use:
Additionally, we have to consider the so-called light color temperature. Color temperature defines the spectral distribution of the light source, in other words it is a measure of the relative mixture of red and blue light being emitted. It is measured in Kelvin. The higher the Kelvin value of a light source, the whiter and later the bluer the light emitted by this source. It is not a measure of brightness (see below). Here is one definition of the Kelvin scale (thresholds may vary according to sources):
On the warm side, the light color is yellowish whereas on the cool side the light color tends to be bluish. For flashlights, we would prefer to be between 5000 to 7000 K as it is the kind of light which best allows for natural color of objects recognition.
Another important characteristic is the amount of light an emitter can output and how efficiently this amount of light is used by the device it is mounted in. Luminous flux is measured in lumen, a measure of power. Luminous intensity is measured in candela, a measure of intensity. The relationship between lumen and candela depends on the beam angle. If the LED is focused into a tighter beam with a reduced beam angle, the luminous intensity (brightness) will increase without actually increasing the amount of light (flux or power). As an example, if you divide by two the beam angle (say from 30Â° to 15Â°) while keeping the light power constant (lumen figure), the light intensity (candela figure) will be multiplied by four.
In most cases, flashlight manufacturers specify the power of their products in lumen but rarely give the candela intensity. As explained above, the latter will depend on reflector design.
Most modern tactical flashlights have multiple brightness modes and special purpose modes such as strobe and SOS beacon.
Yet another feature of your best tactical flashlight is how this bright light is put to use. LEDs produce more or less uniformly smooth light while incandescent light bulbs produce various shapes and dark rings due to their construction and filaments. As explained earlier, reflector design will impact the way the light power is being used. A narrow angle will increase the center beam intensity, therefore extending the reach (also named throw) of the beam. Around the center beam is an area of less intense light named peripheral. A smartly designed reflector can help combine qualities to get a superior product. Reflector is the most important part for eye pleasing light quality.
Best tactical flashlights, however powerful, must also be user friendly. Operation must be straightforward and reliable, adapted to the intended use of the light. It is also desirable that the manufacturer provides optional equipment so as to allow the user to tailor his best tactical flashlight to his own needs.