Hello everyone, I bring to your attention a powerful homemade flashlight. Now you will not be afraid of any darkness. Assembling a homemade product is quite simple, all materials are purchased and are easy to get. For example, the author made the body of the lantern from plumbing pipes and parts for them. This flashlight has lithium batteries, making it easy to charge. So, let's take a closer look at how to assemble such a flashlight!
Materials and tools used by the author:
List of materials:
- lithium batteries;
- ;
- ;
- reflector;
- lens;
- radiator and fan;
- button to turn on;
- wires;
- connector for connecting a charger;
- Charger;
- dye;
- epoxy adhesive;
- stainless steel wire;
- screws, thermal paste and more.
List of tools:
- drill;
- hacksaw for metal;
- soldering iron;
- wire cutters;
- screwdriver;
- marker;
- pliers.
Flashlight manufacturing process:
Step one. Installing an LED on the cooler
We will use a fairly powerful LED, which means that we will definitely need to remove heat from it. For these purposes we will need a small aluminum radiator.
We mark the locations, drill holes and cut threads for the screws. Next, screw the LED to the radiator. Be sure to apply thermal paste to the radiator, otherwise the heat transfer will be low and the LED will overheat.
Next, we install the reflector, the author attaches it with epoxy glue. You can't use hot glue here, as everything gets hot here. Then you can install the lens. To attach the lens, the author used a thin stainless wire. We simply use it to attach the lens bracket to the radiator. That's all, now we just install the fan on the other side of the radiator. We connect the fan to the LED in parallel so that it turns on immediately when the flashlight is turned on. We solder the joints for reliable contact and insulate them with heat shrink.
Step two. Making the body
We will need a piece of PVC sewer pipe as a body; it will contain two batteries of 4000 mAh each. As for the radiator with LED, it will be installed inside the cone-shaped part. Since the filling did not fit into it completely, the author slightly increased the length of the part. He cut a piece from another cone-shaped piece and glued it with superglue. We will also need a plug for the pipes; there will be a connector for the charger.
Step three. Hole for button
We drill a hole in the body, and then bore it with files or cut it out with a stationery knife. Here we will then install a button to turn on the flashlight.
Step four. Attach the filling
We will fix the radiator with the installed LED in the housing. For these purposes we will need a drill and a small diameter drill bit. We drill holes and fasten the whole thing with screws. We cut off the excess parts so as not to interfere. The remaining windows cannot be closed; they are needed for ventilation. In general, it would be good to drill holes in the case near the radiator for cooling. After that, solder the button and install it in its place.
Step five. Understanding batteries
We have two batteries, each with a capacity of 4000 mAh. The author installs them in parallel, for this they are soldered together with “cons”. Between the “cons” we solder the BMS. Thanks to this controller, the batteries will last a long time; it will not allow them to be overcharged or discharged to a critically low value. We also connect the pluses of the batteries with a wire. That's all, now we solder the necessary wires and install the batteries in the case.
Step six. Charging connector
In the plug we install a socket for connecting the charger. It is secured with a nut. We solder the wires, charging should go through the BMS controller. Well, then we install the plug in its place.
LEDs today are built into everything - into toys, lighters, household appliances and even office supplies. But the most useful invention with them is, of course, a flashlight. Most of them are autonomous and produce a powerful glow from small batteries. You won’t get lost in the dark with it, and when working in a dimly lit room, this tool is simply irreplaceable.
Small copies of a wide variety of LED flashlights can be bought in almost any store. They are inexpensive, but the build quality can sometimes be disappointing. Or maybe it’s homemade devices that can be made using the simplest parts. It is interesting, educational and has a developing effect on those who love to make things.
Today we will look at another homemade product - an LED flashlight, made literally from scrap parts. Their cost is no more than a few dollars, and the efficiency of the device is higher than that of many factory models. Interesting? Then do it with us.
How the device works
This time the LED is connected to the battery only through a 3 ohm resistor. Since it contains a ready source of energy, it does not require a storage thyristor and transistor to distribute the voltage, as is the case with the Faraday Eternal Flashlight. An electronic charging module is used to charge the battery. A tiny micromodule provides protection against voltage surges and prevents the battery from overcharging. The device is charged from a USB connector, and on the module itself there is a micro USB connector.Required Parts
- Plastic syringe 20 ml;
- Lenses for LED flashlight with housing;
- Micro button switch;
- 3 Ohm/0.25 W resistor;
- A piece of aluminum plate for the radiator;
- Several copper wires;
- Superglue, epoxy resin or liquid nails.
Assembling a powerful LED flashlight
Preparing an LED with lenses
We take a plastic cap with lenses and mark the circumference of the radiator. It is needed to cool the LED. We mark the mounting grooves and holes on the aluminum plate and cut out the radiator according to the markings. This can be done, for example, using a drill.
We take out the magnifying lenses for a while, they won’t be needed now. Glue the radiator plate onto the back of the cap with superglue. The holes and grooves in the cap and radiator must match.
We tin the LED contacts and solder them with copper wiring. We protect the contacts with heat-shrinkable casings and warm them up with a lighter. We insert an LED with wiring from the front side of the cap.
Processing the flashlight body from a syringe
We unlock the piston with the handle of the syringe; we will no longer need them. We cut the needle cone with a painting knife.We completely clean the end of the syringe, making holes in it for the LED contacts of the flashlight.
We attach the lantern cap to the end surface of the syringe using any suitable glue, for example, epoxy resin or liquid nails. Don’t forget to place the LED contacts inside the syringe.
Connecting the charging micromodule and battery
We attach terminals with contacts to the lithium battery and insert it into the syringe body. We tighten the copper contacts to clamp them with the battery body.
The syringe has only a few centimeters of free space, which is not enough for the charging module. Therefore, it will have to be divided into two parts.
We run a paint knife in the middle of the module board and break it along the cut line. Using double tape we connect both halves of the board together.
We tin the open contacts of the module and solder them with copper wiring.
Final assembly of the flashlight
We solder a resistor to the module board and connect it to the micro-button, insulating the contacts with heat shrink.
We solder the remaining three contacts to the module according to its connection diagram. We connect the micro button last, checking the operation of the LED.
When purchasing or assembling new LED flashlights, you should definitely pay attention to the LED used. If you are purchasing a lantern only to illuminate a dark street, then there is a huge choice - choose any one with a bright white LED. But if you want to buy a portable lighting device with characteristics for more complex tasks, the important point here is the choice of the appropriate luminous flux, that is, the ability of the device to illuminate a large space with a powerful beam.
Main characteristics
LEDs are responsible for the quality of light that the flashlight emits. The stability of lighting depends on many characteristics, including current consumption, light flux and color temperature. Among the trendsetters, it is worth noting the company Cree; in its assortment you can find very bright LEDs for flashlights.
Modern pocket models are created using a single LED, the power of which reaches 1, 2, or 3 W. The indicated electrical characteristics are the properties of various LED models from well-known brands. The intensity of the light rays or luminous flux is an indicator that depends on the type of LED and the manufacturer. The manufacturer also indicates the number of lumens in the characteristics.
This indicator directly correlates with the color temperature of the light. Light-emitting diodes can produce up to 200 lumens per watt and are produced today in different temperatures to glow: warm yellowish or cool white.
Lanterns with a warm white tint produce a pleasant light to the human eye, but they are less bright. Light with a neutral color temperature effectively allows the smallest elements to be seen. Cool white lighting is usually typical for models with a huge beam range, but can irritate the eyes during prolonged use.
If the temperature reaches approximately 50 °C, then the life of the crystal can be up to 200,000 hours, but this is not justified from an economic point of view. For this reason, many companies produce products that can withstand operating temperatures of up to 85 °C, while saving on cooling costs. If the temperature exceeds 150 °C, the equipment may completely fail.
The color rendering index is a qualitative indicator that characterizes the ability of an LED to illuminate a space without distorting the actual shade. LEDs for flashlights with a color rendering source characteristic of 75 CRI or more are a good option. An important element of the LED is the lens, thanks to which the angle of dispersion of the light fluxes is set, that is, the range of the beam is determined.
In any technical specification of an LED, the emission angle must be noted. For any of the models, this characteristic is considered individual and usually varies in the range from 20 to 240 degrees. High-power LED flashlights have an angle of approximately 120°C and generally include a reflector and an additional lens.
Although today we can see a strong leap in the production of high-power LEDs consisting of multiple crystals, global brands are still producing LEDs with lower power. They are produced in a small case that does not exceed 10 mm in width. In a comparative analysis, one can notice that one such powerful crystal has a less reliable circuit and dispersion angle than a pair of similar elements simultaneously in a single housing.
It would not be amiss to recall the four-pin “SuperFlux” LEDs, the so-called “piranha”. These flashlight LEDs have improved specifications. The piranha LED has the following main advantages:
- the light flux is distributed evenly;
- no need to remove heat;
- lower price.
Types of LEDs
There are many flashlights with improved features available in the market today. The most popular LEDs are from Cree Inc.: XR-E, XP-E, XP-G, XM-L. Today the latest XP-E2, XP-G2, XM-L2 are also popular - they are mainly used in small flashlights. But, for example, Cree MT-G2 and MK-R LEDs from Luminus are widely used in huge models of search lights that can operate simultaneously from a pair of batteries.
In addition, LEDs are usually distinguished by brightness - there is a special code thanks to which you can sort LEDs by this parameter.
When comparing some diodes with others, it is worth paying attention to their dimensions, or rather, to the area of the light-emitting crystals. If the area of such a crystal is small, then it is easier to concentrate its light into a narrow beam. If you want to get a narrow beam from XM-L LEDs, you will need to use a very large reflector, which negatively affects the weight and dimensions of the housing. But with small reflectors on such an LED, a fairly effective pocket flashlight will come out.
Application area of LEDs
Mostly, when choosing flashlights, consumers choose models with the maximum beam of light, but in many cases they do not need this option. In many cases, such equipment is used to illuminate a nearby area or an object that is no more than 10,000 m away. A long-range flashlight shines at 100 m, although in many cases with a rather narrow beam that poorly illuminates the surrounding area. As a result, when illuminating a distant object with such lighting devices, the user will not notice those objects that are located in close proximity to him.
Let's look at a comparison of the tonality of light produced by LEDs: warm, neutral and cold. When selecting the appropriate flashlight light temperature, the following important points must be taken into account: LEDs with a warm glow can minimally distort the color of the illuminated objects, but they have lower brightness than neutral-spectrum LEDs.
When choosing a powerful search or tactical flashlight, where the brightness of the device is an important point, it is recommended to select an LED with a cold spectrum of light. If a flashlight is needed for everyday life, tourism purposes, or for use in a head-mounted model, then proper color rendering is important, which means LEDs with warm light will be more advantageous. A neutral LED is the golden mean in all respects.
Not taking into account the cheapest flashlights, which only have a single button, many flashlights have a couple of operating modes, including strobe and SOS modes. The non-brand model has the following operating options: the highest power rating, medium power and “strobe”. In addition, the average power is basically equal to 50% of the highest brightness of the light, and the lowest is 10%.
Branded models have a more complex structure. Here you can control the operating mode using a button, rotating the “head”, turning the magnetic rings and a combination of all of the above.
Let's consider LED products, ranging from old 5 mm to super-bright high-power LEDs whose power reaches 10 W.
To choose the “right” flashlight for your needs, you need to understand what kinds of LED flashlights there are and their characteristics.
What diodes are used in flashlights?
High-power LED lights started with 5mm sensor devices.
LED flashlights in completely different designs, from pocket to camping, became widespread in the mid-2000s. Their price has dropped noticeably, and the brightness and long service life of a single battery charge have played their role.
5mm white ultra-bright LEDs consume 20 to 50 mA of current, with a voltage drop of 3.2-3.4 volts. Luminous intensity – 800 mcd.
They perform very well in miniature keychain flashlights. The small size allows you to carry this flashlight with you. They are powered either by “mini-pen” batteries or by several round “tablets”. Often used in flashlight lighters.
These are the types of LEDs that have been installed in Chinese lanterns for many years, but their life is gradually coming to an end.
In search lights with a large reflector size, it is possible to mount dozens of such diodes, but such solutions are gradually fading into the background, and the choice of buyers falls in favor of flashlights with powerful Cree-type LEDs.
Search light with 5mm LEDs These flashlights operate on AA, AAA batteries or rechargeable batteries. They are inexpensive and inferior both in brightness and quality to modern flashlights with more powerful crystals, but more on that below.
In the further development of flashlights, manufacturers have gone through many options, but the market for quality products is occupied by flashlights with powerful matrices or discrete LEDs.
What kind of LEDs are used in high-power flashlights?
Powerful flashlights mean modern flashlights of various types, ranging from those the size of a finger to huge search flashlights.
In such products, the Cree brand is relevant in 2017. This is the name of an American company. Its products are considered one of the most advanced in the field of LED technology. An alternative is LED from the manufacturer Luminus.
Such things are significantly superior to LEDs from Chinese lanterns.
What Cree LEDs are most commonly installed in flashlights?
Models are called consisting of three or four characters, separated by a hyphen. So diodes Cree XR-E, XR-G, XM-L, XP-E. Models XP-E2, G2 are most often used for small flashlights, while XM-L and L2 are very versatile.
They are used starting from the so-called. EDC flashlights (everyday carry) range from small flashlights smaller than the palm of your hand to large, serious search flashlights.
Let's look at the characteristics of high-power LEDs for flashlights.
| Name | Cree XM-L T6 | Cree XM-L2 | Cree XP-G2 | Cree XR-E |
| Photo |  |
|||
| U, V | 2,9 | 2,85 | 2,8 | 3,3 |
| I, mA | 700 | 700 | 350 | 350 |
| P, W | 2 | 2 | 1 | 1 |
| Operating temperature, °C | ||||
| Luminous flux, Lm | 280 | 320 | 145 | 100 |
| Illumination angle, ° | 125 | 125 | 115 | 90 |
| Color rendering index, Ra | 80-90 | 70-90 | 80-90 | 70-90 |
The main characteristic of LEDs for flashlights is luminous flux. The brightness of your flashlight and the amount of light that the source can provide depends on it. Different LEDs, consuming the same amount of energy, can differ significantly in brightness.
Let's look at the characteristics of LEDs in large floodlight flashlights :
| Name | ||||
| Photo |  |  |  |  |
| U, V | 5,7; 8,55; 34,2; | 6; 12; | 3,6 | 3,5 |
| I, mA | 1100; 735; 185; | 2500; 1250 | 5000 | 9000...13500 |
| P, W | 6,3 | 8,5 | 18 | 20...40 |
| Operating temperature, °C | ||||
| Luminous flux, Lm | 440 | 510 | 1250 | 2000...2500 |
| Illumination angle, ° | 115 | 120 | 100 | 90 |
| Color rendering index, Ra | 70-90 | 80-90 | 80-90 |
Sellers often do not indicate the full name of the diode, its type and characteristics, but an abbreviated, slightly different alphanumeric marking:
- For XM-L: T5; T6; U2;
- XP-G: R4; R5; S2;
- XP-E: Q5; R2; R;
- for XR-E: P4; Q3; Q5; R.
The flashlight may be called “EDC T6 Flashlight”, there is more than enough information in such brevity.
Flashlight repair
Unfortunately, the price of such flashlights is quite high, as are the diodes themselves. And it is not always possible to purchase a new flashlight in case of a breakdown. Let's figure out how to change the LED in a flashlight.
To repair a flashlight, you need a minimum set of tools:
- Soldering iron;
- flux;
- solder;
- screwdriver;
- multimeter
To get to the light source you need to unscrew the head of the flashlight; it is usually attached to a threaded connection.
In diode test or resistance measurement mode, check that the LED is working properly. To do this, touch the black and red probes to the LED terminals, first in one position, and then swap the red and black ones.
If the diode is working properly, then in one of the positions there will be low resistance, and in the other - high. This way you determine that the diode is working and conducts current in only one direction. The diode may emit faint light during testing.
Otherwise, there will be a short circuit or high resistance (open) in both positions. Then you need to replace the diode in the flashlight.
Now you need to unsolder the LED from the flashlight and, observing the polarity, solder in a new one. Be careful when choosing an LED, consider its current consumption and the voltage for which it is designed.
If you neglect these parameters, in the best case the flashlight will quickly dry up, in the worst case the driver will fail.
A driver is a device for powering an LED with stabilized current from different sources. Drivers are manufactured industrially for power supply from a 220 volt network, from a car electrical network - 12-14.7 volts, from Li-ion batteries, for example, size 18650. Most powerful flashlights are equipped with a driver.
Increasing the power of the flashlight
If you are not satisfied with the brightness of your flashlight or you have figured out how to replace the LED in a flashlight and want to upgrade it, before buying heavy-duty models, study the basic principles of LED operation and the limitations in their operation.
Diode matrices do not like overheating - this is the main postulate! And replacing the LED in a flashlight with a more powerful one can lead to this situation. Pay attention to models in which more powerful diodes are installed and compare them with yours; if they are similar in size and design, change them.
If your flashlight is smaller, additional cooling will be required. We wrote more about making radiators with our own hands.
If you try to install such a giant as the Cree MK-R into a miniature keychain flashlight, it will quickly fail from overheating and it will be a waste of money. A slight increase in power (a couple of watts) is acceptable without upgrading the flashlight itself.
Otherwise, the process of replacing the brand of LED in a flashlight with a more powerful one is described above.
Police lights
LED Police flashlight with shocker Such lanterns shine brightly and can act as a means of self-defense. However, they also have problems with LEDs.
How to replace the LED in a Police flashlight
The wide range of models is very difficult to cover in one article, but general recommendations for repairs can be given.
- When repairing a flashlight with a stun gun, be careful, preferably use rubber gloves to avoid electric shock.
- Flashlights with dust and moisture protection are assembled on a large number of screws. They differ in length, so make notes from where you unscrewed this or that screw.
- The optical system of the Police flashlight allows you to adjust the diameter of the light spot. When disassembling the body, make marks on the position in which the parts were before removal, otherwise it will be difficult to put the unit with the lens back.
Replacing the LED, voltage converter unit, driver, and battery is possible using a standard soldering kit.
What kind of LEDs are used in Chinese lanterns?
Many products are now purchased on Aliexpress, where you can find both original products and Chinese copies that do not correspond to the stated description. The price for such devices is comparable to the price of the original.
In a flashlight that claims a Cree LED, it may not actually be there; at best, there will be a diode of a frankly different type, at worst, one that will be difficult to distinguish from the original in appearance.
What might this entail? Cheap LEDs are made in low-tech conditions and do not produce the declared power. They have low efficiency, which is why they have increased heating of the case and crystal. As has already been said, overheating is the worst enemy for LED devices.
This happens because when heated, the current through the semiconductor increases, as a result of which the heating becomes even stronger, the power is released even more, and this avalanche-like leads to breakdown or breakage of the LED.
If you try and spend time searching for information, you can determine the originality of the product.
Compare the original and fake cree LatticeBright is a Chinese LED manufacturer that makes products very similar to Cree, probably a coincidence of design thought (sarcasm).
Comparison of the Chinese copy and the original Cree On the substrates these clones look like this. You can notice the variety of shapes of LED substrates produced in China.
Detecting counterfeit by LED substrate Counterfeits are made quite skillfully; many sellers do not indicate this “brand” in the product description and where the LEDs for flashlights are produced. The quality of such diodes is not the worst among Chinese junk, but it is also far from the original.
Installing an LED instead of an incandescent lamp
Many people have horse races or incandescent lamps collecting dust in old things, and you can easily turn it into LED. For this, there are either ready-made solutions or homemade ones.
Using a broken light bulb and LEDs, with a little ingenuity and solder, you can make a great replacement.
In this case, an iron barrel is needed to improve heat removal from the LED. Next you need to solder all the parts to each other and secure with glue.
When assembling, be careful - avoid shorting the leads; hot glue or heat shrink tubing will help with this. The central contact of the lamp must be unsoldered - a hole will form. Pass the resistor lead through it.
Next you need to solder the free lead of the LED to the base, and the resistor to the central contact. For a voltage of 12 volts, a 500 Ohm resistor is needed, and for a voltage of 5 V – 50-100 Ohms, for power supply from a Li-ion 3.7V battery – 10-25 Ohms.
How to make an LED lamp from an incandescent lamp Selecting an LED for a flashlight is much more difficult than replacing it. It is necessary to take into account a lot of parameters: from brightness and dispersion angle to heating of the case.
In addition, we must not forget about the power supply for the diodes. If you master everything described above, your devices will shine for a long time and with high quality!
To move or work in the dark, you need a flashlight. They come in different types ranging from small pocket ones to large military or search ones. The design and power of a flashlight depends on its purpose, for example, in order to illuminate a keyhole in a dark entrance, a low-power pocket flashlight is enough, while tourists need a camping flashlight that can shine in all directions, like a kerosene lamp, and a waterproof, impact-resistant flashlight to move around in poor visibility conditions. In this article, we'll look at how to choose a powerful LED rechargeable flashlight for your needs.
Criterias of choice
To make the right choice of LED flashlight, you need to consider a number of factors, including:
- Type and power of LEDs. Brightness and energy consumption depend on them.
- Colorful temperature. Comfort during use depends on it.
- Capacity and type of batteries. Affects the duration of work.
- Reflector and optical system. It depends on them how focused the light flux will be.
- Design features. They affect impact resistance, resistance to water and dust, ease of use, carrying and holding in hands.
Types of LEDs
Flashlights can use various LEDs, and every year more and more powerful and brighter models are released. However, this does not prevent us from dividing them into the main types used:
- 5 mm LEDs. Previously used in all LED flashlights, now this is an outdated type of LEDs, the reason for this is their low brightness and significant energy consumption. To get a strong luminous flux from a flashlight, you have to install many of these LEDs, which is not always possible, since such a flashlight will not fit in your pocket.
The photo below shows an example of 5 mm LED lights
5 mm LEDs in flashlights- SMD LEDs.
Various types can be used - 5050, 3528, 5730 and others. They have two advantages - high power and small dimensions. This allows you to achieve good luminous flux for small lanterns. Matrixes of such LEDs are installed on camping lanterns and other types of lanterns with a diffused light mode function. It allows you to illuminate a large area from one flashlight with a diffused stream, albeit with losses of illumination, rather than a focused bright beam.
Panel with diffused light on the flashlight - Powerful LEDs 1, 3, 5 Watt. Two groups can be distinguished here:
- Noname LEDs.
- Branded LEDs, for example, the CREE brand and its popular XM-l models and others.
Flashlight with powerful LEDs Accordingly, cheap Chinese LEDs are installed in products in the budget price segment, and branded LEDs are installed in more expensive flashlight models. The differences lie in the specific luminous flux - the number of Lumens per 1 Watt of power, in other words, the efficiency. This determines not only how brightly the flashlight will shine, but also how long it will operate on a single battery charge. It is also observed that cheap high-power LEDs fail faster, like any noname products.
What kind of LEDs are installed in high-power flashlights?
As already mentioned, the most common LEDs are from CREE; we have prepared a summary table with the characteristics of popular models of LEDs for flashlights.
| Name | Cree XM-L T6 | Cree XM-L2 | Cree XP-G2 | Cree XR-E |
| Photo | 
| 
| 
| |
| U, V | 2,9 | 2,85 | 2,8 | 3,3 |
| I, mA | 700 | 700 | 350 | 350 |
| P, W | 2 | 2 | 1 | 1 |
| Operating temperature, °C | <150 | <85 | <85 | <85 |
| Luminous flux, Lm | 280 | 320 | 145 | 100 |
| Illumination angle, ° | 125 | 125 | 115 | 90 |
| Color rendering index, Ra | 80-90 | 70-90 | 80-90 | 70-90 |
And more powerful.
| Name | Cree MT-G2 | Cree MK-R | Luminus SST-50 | Luminus SBT-90 |
| Photo | 
| 
| 
| 
|
| U, V | 5,7; 8,55; 34,2; | 6; 12; | 3,6 | 3,5 |
| I, mA | 1100; 735; 185; | 2500; 1250 | 5000 | 9000…13500 |
| P, W | 6,3 | 8,5 | 18 | 20…40 |
| Operating temperature, °C | <85 | <150 | <85 | <85 |
| Luminous flux, Lm | 440 | 510 | 1250 | 2000…2500 |
| Illumination angle, ° | 115 | 120 | 100 | 90 |
| Color rendering index, Ra | <70 | 70-90 | 80-90 | 80-90 |
But LEDs can be designated in a different way, with a more concise marking, for example:
- XM-L: T5, T6, U2.
- XP-G: R4, R5, S2.
- XP-E: Q5, R2, R.
- XR-E: P4, Q3, Q5.
This video shows the process of replacing such an LED.
Colorful temperature
For flashlights, color temperature is not as important as color temperature for indoor lighting. However, it is worth paying attention to it. is perceived as softer to the eye, and neutral and cool shades make you more alert and focused.
Color temperature of flashlights Batteries
Now the leading place in sales is occupied by Li-ion batteries. The reason for this is their large capacity with small dimensions, good current output, and almost complete absence of memory effect. There are also disadvantages that should be remembered - in the cold, lithium-ion batteries discharge faster than in the heat, and if a lithium can is short-circuited without protection, a reaction will occur with a large release of heat, even leading to an explosion.
18650 battery Powerful LED flashlights are most often equipped with lithium batteries; in addition to them, there are also other types of batteries:
- Ni-Cd – nickel-cadmium.
- Ni-Mh – nickel metal hydride.
- Pb – lead.
But recently they are used in flashlights less and less.
Reflector and optical system
The design of the reflector and the presence of lenses affect the shape of the light spot. Some models have the ability to move the lens, which allows you to focus the light beam. The lenses collect the light flux, as a result you get a more illuminated space, but a smaller area than without focusing.
Focusing the light beam But different tasks require a light beam of different sizes. For example, if the flashlight will be used to repair a car, then in most cases, a model with the ability to focus will be better suited to illuminate a large area when searching for a problem, and then narrow the beam of light to a small but bright point when eliminating it or studying it in detail. At the same time, a focused spot is not needed to move in the dark; flashlights that widely illuminate the space in front of you are better suited.
Types by purpose
In addition to the elements used and their features, when choosing flashlights, they are also distinguished by their purpose. To choose the right LED flashlight for specific tasks, you need to clearly understand what you will use it for, because there are no universal models as such.
Military and special devices
The main feature of military flashlights and special-purpose lighting devices is, first of all, the high strength of the housing and its resistance to moisture. Such devices also include search lights that shine brightly and far away, which allows you to find something in difficult conditions, for example, in a forest or in large rooms.
Military lantern Models for technical personnel
Flashlights for technical personnel must be compact and have a long operating time. Their size and weight should not complicate the movement of the worker, who already carries tools and parts with him. An excellent addition to such a device would be the ability to focus the light beam and a head mount.
Headlamp For outdoor recreation and tourism
Search and camping lanterns, as well as those used for military purposes, are suitable for tourists, since the conditions in which they will work are similar - humidity, the possibility of bumps and falls, etc. A camping lantern resembles a kerosene lamp and is a broad-directional or all-directional lighting fixture. It is convenient to use, for example, when preparing for an overnight stay and dinner. You should also pay attention to flashlights with a built-in generator. They can either operate without batteries or be recharged by operating the generator lever (rotation or rhythmic pressing of the handle, depending on the design).
Camping lantern How to convert an ordinary flashlight into an LED one
Let's look at how to make an LED flashlight with your own hands. To do this you will need the following set of parts and tools:
- Frame. You can take it from an old lantern or make it yourself, or print it on a 3D printer.
- LEDs. Selected individually.
- or resistors to limit their current.
- Battery.
- A charge controller for batteries or a charger suitable for the type of battery used.
- Power button or toggle switch.
If you use high-power LEDs, you will need a circuit board on an aluminum substrate.
LED substrate To improve heat dissipation, you need to use a radiator, you can take it from the motherboard. Small radiators are installed on chipsets, northbridge, power switches and other board elements.
LEDs on the heatsink from the motherboard. Don't forget to coat everything with thermal paste! To charge and protect the 18650 battery, you can use the TP4056 board with protection, it can be ordered on Aliexpress or bought at a radio store, it costs 20-50 rubles.
Lithium battery charging board based on tp4056 Interesting: This board can be used to replace disposable batteries in a flashlight or to convert any device to batteries.
We pack this in the flashlight body, if it is iron, as in the photo, do not forget to provide insulation for all boards.
To power the LEDs, you can use a specialized driver or a switching boost converter, for example, MT3608. The output voltage is set using a multi-turn potentiometer; in the photo below it can be recognized by its blue housing.
Expert opinion
Alexey Bartosh
Specialist in repair and maintenance of electrical equipment and industrial electronics.
Ask a question to an expertIf you use a driver for power, its main characteristics are the output current and power; it determines how many LEDs you can connect in series.
It is necessary to select a voltage such that the current is 10-30% lower than the rated current. For 1 W LEDs, the rated current is in the range of 300-350 mA.
Boost converter in a flashlight A less complicated way is to select the operating mode for heating the LEDs. That is, gradually increase the voltage, testing the radiator by touch; it should not heat up, or its temperature should be less than 50 degrees Celsius, this is the temperature when your hand still tolerates it when you touch it and you don’t want to pull it back. This is an imprecise method, so it is better to focus on both current and heating.
Homemade flashlight assembly The second option is simpler. To replace an incandescent lamp with an LED, you need to take an old light bulb, break the bulb, remove all the insides so that only the base remains. Next, an insulated LED lead with a soldered resistor selected for the appropriate voltage is inserted into the base.