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 shine less brightly. Light with a neutral color temperature effectively allows you to see the smallest elements. 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.
Boruit heavy duty headlamp. For lighting during fishing, hunting and household work.
For safety and the ability to continue active activities in the dark, a person needs artificial lighting. Primitive people pushed back the darkness by setting fire to tree branches, then they came up with a torch and a kerosene stove. And only after the invention of the prototype of a modern battery by the French inventor Georges Leclanche in 1866, and the incandescent lamp in 1879 by Thomson Edison, did David Mizell have the opportunity to patent the first electric flashlight in 1896.
Since then, nothing has changed in the electrical circuit of new flashlight samples, until in 1923, Russian scientist Oleg Vladimirovich Losev found a connection between luminescence in silicon carbide and the p-n junction, and in 1990, scientists managed to create an LED with greater luminous efficiency, allowing them to replace a light bulb incandescent The use of LEDs instead of incandescent lamps, due to the low energy consumption of LEDs, has made it possible to repeatedly increase the operating time of flashlights with the same capacity of batteries and accumulators, increase the reliability of flashlights and practically remove all restrictions on the area of their use.
The LED rechargeable flashlight that you see in the photograph came to me for repair with a complaint that the Chinese Lentel GL01 flashlight I bought the other day for $3 does not light, although the battery charge indicator is on.
The external inspection of the lantern made a positive impression. High-quality casting of the case, comfortable handle and switch. The plug rods for connecting to a household network for charging the battery are made retractable, eliminating the need to store the power cord.
Attention! When disassembling and repairing the flashlight, if it is connected to the network, you should be careful. Touching unprotected parts of your body to uninsulated wires and parts may result in electric shock.
How to disassemble the Lentel GL01 LED rechargeable flashlight
Although the flashlight was subject to warranty repair, remembering my experiences during the warranty repair of a faulty electric kettle (the kettle was expensive and the heating element in it burned out, so it was not possible to repair it with my own hands), I decided to do the repair myself.
It was easy to disassemble the lantern. It is enough to turn the ring that secures the protective glass a small angle counterclockwise and pull it off, then unscrew several screws. It turned out that the ring is fixed to the body using a bayonet connection.
After removing one of the halves of the flashlight body, access to all its components appeared. On the left in the photo you can see a printed circuit board with LEDs, to which a reflector (light reflector) is attached using three screws. In the center there is a black battery with unknown parameters; there is only a marking of the polarity of the terminals. To the right of the battery there is a printed circuit board for the charger and indication. On the right is a power plug with retractable rods.
Upon closer examination of the LEDs, it turned out that there were black spots or dots on the emitting surfaces of the crystals of all LEDs. It became clear even without checking the LEDs with a multimeter that the flashlight did not light due to their burnout.
There were also blackened areas on the crystals of two LEDs installed as backlight on the battery charging indication board. In LED lamps and strips, one LED usually fails, and acting as a fuse, it protects the others from burning out. And all nine LEDs in the flashlight failed at the same time. The voltage on the battery could not increase to a value that could damage the LEDs. To find out the reason, I had to draw an electrical circuit diagram.
Finding the cause of the flashlight failure
The electrical circuit of the flashlight consists of two functionally complete parts. The part of the circuit located to the left of switch SA1 acts as a charger. And the part of the circuit shown to the right of the switch provides the glow.
The charger works as follows. The voltage from the 220 V household network is supplied to the current-limiting capacitor C1, then to a bridge rectifier assembled on diodes VD1-VD4. From the rectifier, voltage is supplied to the battery terminals. Resistor R1 serves to discharge the capacitor after removing the flashlight plug from the network. This prevents electric shock from capacitor discharge in the event of your hand accidentally touching two pins of the plug at the same time.
LED HL1, connected in series with current-limiting resistor R2 in the opposite direction with the upper right diode of the bridge, as it turns out, always lights up when the plug is inserted into the network, even if the battery is faulty or disconnected from the circuit.
The operating mode switch SA1 is used to connect separate groups of LEDs to the battery. As you can see from the diagram, it turns out that if the flashlight is connected to the network for charging and the switch slide is in position 3 or 4, then the voltage from the battery charger also goes to the LEDs.
If a person turns on the flashlight and discovers that it does not work, and, not knowing that the switch slide must be set to the “off” position, about which nothing is said in the flashlight’s operating instructions, connects the flashlight to the network for charging, then at the expense If there is a voltage surge at the output of the charger, the LEDs will receive a voltage significantly higher than the calculated one. A current that exceeds the permissible current will flow through the LEDs and they will burn out. As an acid battery ages due to sulfation of the lead plates, the battery charge voltage increases, which also leads to LED burnout.
Another circuit solution that surprised me was the parallel connection of seven LEDs, which is unacceptable, since the current-voltage characteristics of even LEDs of the same type are different and therefore the current passing through the LEDs will also not be the same. For this reason, when choosing the value of resistor R4 based on the maximum permissible current flowing through the LEDs, one of them may overload and fail, and this will lead to an overcurrent of parallel-connected LEDs, and they will also burn out.
Rework (modernization) of the electrical circuit of the flashlight
It became obvious that the failure of the flashlight was due to errors made by the developers of its electrical circuit diagram. To repair the flashlight and prevent it from breaking again, you need to redo it, replacing the LEDs and making minor changes to the electrical circuit.
In order for the battery charge indicator to actually signal that it is charging, the HL1 LED must be connected in series with the battery. To light an LED, a current of several milliamps is required, and the current supplied by the charger should be about 100 mA.
To ensure these conditions, it is enough to disconnect the HL1-R2 chain from the circuit in the places indicated by red crosses and install an additional resistor Rd with a nominal value of 47 Ohms and a power of at least 0.5 W in parallel with it. The charge current flowing through Rd will create a voltage drop of about 3 V across it, which will provide the necessary current for the HL1 indicator to light. At the same time, the connection point between HL1 and Rd must be connected to pin 1 of switch SA1. In this simple way, it will be impossible to supply voltage from the charger to the LEDs EL1-EL10 while charging the battery.
To equalize the magnitude of the currents flowing through the LEDs EL3-EL10, it is necessary to exclude resistor R4 from the circuit and connect a separate resistor with a nominal value of 47-56 Ohms in series with each LED.
Electrical diagram after modification
Minor changes made to the circuit increased the information content of the charge indicator of an inexpensive Chinese LED flashlight and greatly increased its reliability. I hope that LED flashlight manufacturers will make changes to the electrical circuits of their products after reading this article.
After modernization, the electrical circuit diagram took the form as in the drawing above. If you need to illuminate the flashlight for a long time and do not require high brightness of its glow, you can additionally install a current-limiting resistor R5, thanks to which the operating time of the flashlight without recharging will double.
LED battery flashlight repair
After disassembly, the first thing you need to do is restore the functionality of the flashlight, and then start upgrading it.
Checking the LEDs with a multimeter confirmed that they were faulty. Therefore, all the LEDs had to be desoldered and the holes freed from solder to install new diodes.
Judging by its appearance, the board was equipped with tube LEDs from the HL-508H series with a diameter of 5 mm. LEDs of type HK5H4U from a linear LED lamp with similar technical characteristics were available. They came in handy for repairing the lantern. When soldering LEDs to the board, you must remember to observe polarity; the anode must be connected to the positive terminal of the battery or battery.
After replacing the LEDs, the PCB was connected to the circuit. The brightness of some LEDs was slightly different from others due to the common current-limiting resistor. To eliminate this drawback, it is necessary to remove resistor R4 and replace it with seven resistors, connected in series with each LED.
To select a resistor that ensures optimal operation of the LED, the dependence of the current flowing through the LED on the value of the series-connected resistance was measured at a voltage of 3.6 V, equal to the voltage of the flashlight battery.
Based on the conditions for using the flashlight (in case of interruptions in the power supply to the apartment), high brightness and illumination range were not required, so the resistor was chosen with a nominal value of 56 Ohms. With such a current-limiting resistor, the LED will operate in light mode, and energy consumption will be economical. If you need to squeeze out maximum brightness from the flashlight, then you should use a resistor, as can be seen from the table, with a nominal value of 33 Ohms and make two modes of operation of the flashlight by turning on another common current-limiting resistor (in the diagram R5) with a nominal value of 5.6 Ohms.
To connect a resistor in series with each LED, you must first prepare the printed circuit board. To do this, you need to cut any one current-carrying path on it, suitable for each LED, and make additional contact pads. The current-carrying paths on the board are protected by a layer of varnish, which must be scraped off with a knife blade to the copper, as in the photograph. Then tin the bare contact pads with solder.
It is better and more convenient to prepare a printed circuit board for mounting resistors and soldering them if the board is mounted on a standard reflector. In this case, the surface of the LED lenses will not be scratched, and it will be more convenient to work.
Connecting the diode board after repair and modernization to the flashlight battery showed that the brightness of all LEDs was sufficient for illumination and the same brightness.
Before I had time to repair the previous lamp, the second one was repaired, with the same fault. I didn’t find any information about the manufacturer or technical specifications on the flashlight body, but judging by the manufacturing style and the cause of the breakdown, the manufacturer is the same, Chinese Lentel.
Based on the date on the flashlight body and on the battery, it was possible to establish that the flashlight was already four years old and, according to its owner, the flashlight worked flawlessly. It is obvious that the flashlight lasted a long time thanks to the warning sign “Do not turn on while charging!” on a hinged lid covering a compartment in which a plug is hidden for connecting the flashlight to the mains for charging the battery.
In this flashlight model, the LEDs are included in the circuit according to the rules; a 33 Ohm resistor is installed in series with each one. The resistor value can be easily recognized by color coding using an online calculator. A check with a multimeter showed that all the LEDs were faulty, and the resistors were also broken.
An analysis of the cause of the failure of the LEDs showed that due to sulfation of the acid battery plates, its internal resistance increased and, as a result, its charging voltage increased several times. During charging, the flashlight was turned on, the current through the LEDs and resistors exceeded the limit, which led to their failure. I had to replace not only the LEDs, but also all the resistors. Based on the above-mentioned operating conditions of the flashlight, resistors with a nominal value of 47 Ohms were chosen for replacement. The resistor value for any type of LED can be calculated using an online calculator.
Redesign of the battery charging mode indication circuit
The flashlight has been repaired, and you can begin making changes to the battery charging indication circuit. To do this, it is necessary to cut the track on the printed circuit board of the charger and indication in such a way that the HL1-R2 chain on the LED side is disconnected from the circuit.
The lead-acid AGM battery was deeply discharged, and an attempt to charge it with a standard charger was unsuccessful. I had to charge the battery using a stationary power supply with a load current limiting function. A voltage of 30 V was applied to the battery, and at the first moment it consumed only a few mA of current. Over time, the current began to increase and after a few hours increased to 100 mA. After fully charging, the battery was installed in the flashlight.
Charging deeply discharged lead-acid AGM batteries with increased voltage as a result of long-term storage allows you to restore their functionality. I have tested the method on AGM batteries more than a dozen times. New batteries that do not want to be charged from standard chargers are restored to almost their original capacity when charged from a constant source at a voltage of 30 V.
The battery was discharged several times by turning on the flashlight in operating mode and charged using a standard charger. The measured charge current was 123 mA, with a voltage at the battery terminals of 6.9 V. Unfortunately, the battery was worn out and was enough to operate the flashlight for 2 hours. That is, the battery capacity was about 0.2 Ah and for long-term operation of the flashlight it is necessary to replace it.
The HL1-R2 chain on the printed circuit board was successfully placed, and it was necessary to cut only one current-carrying path at an angle, as in the photograph. The cutting width must be at least 1 mm. Calculation of the resistor value and testing in practice showed that for stable operation of the battery charging indicator, a 47 Ohm resistor with a power of at least 0.5 W is required.
The photo shows a printed circuit board with a soldered current-limiting resistor. After this modification, the battery charge indicator lights up only if the battery is actually charging.
Modernization of the operating mode switch
To complete the repair and modernization of the lights, it is necessary to resolder the wires at the switch terminals.
In models of flashlights being repaired, a four-position slide-type switch is used to turn on. The middle pin in the photo shown is general. When the switch slide is in the extreme left position, the common terminal is connected to the left terminal of the switch. When moving the switch slide from the extreme left position to one position to the right, its common pin is connected to the second pin and, with further movement of the slide, sequentially to pins 4 and 5.
To the middle common terminal (see photo above) you need to solder a wire coming from the positive terminal of the battery. Thus, it will be possible to connect the battery to a charger or LEDs. To the first pin you can solder the wire coming from the main board with LEDs, to the second you can solder a current-limiting resistor R5 of 5.6 Ohms to be able to switch the flashlight to an energy-saving operating mode. Solder the conductor coming from the charger to the rightmost pin. This will prevent you from turning on the flashlight while the battery is charging.
Repair and modernization
LED rechargeable spotlight "Foton PB-0303"
I received another copy of a series of Chinese-made LED flashlights called the Photon PB-0303 LED spotlight for repair. The flashlight did not respond when the power button was pressed; an attempt to charge the flashlight battery using a charger was unsuccessful.
The flashlight is powerful, expensive, costs about $20. According to the manufacturer, the luminous flux of the flashlight reaches 200 meters, the body is made of impact-resistant ABS plastic, and the kit includes a separate charger and a shoulder strap.
The Photon LED flashlight has good maintainability. To gain access to the electrical circuit, simply unscrew the plastic ring holding the protective glass, rotating the ring counterclockwise when looking at the LEDs.
When repairing any electrical appliances, troubleshooting always starts with the power source. Therefore, the first step was to measure the voltage at the terminals of the acid battery using a multimeter turned on in mode. It was 2.3 V, instead of the required 4.4 V. The battery was completely discharged.
When connecting the charger, the voltage at the battery terminals did not change, it became obvious that the charger was not working. The flashlight was used until the battery was completely discharged, and then it was not used for a long time, which led to a deep discharge of the battery.
It remains to check the serviceability of the LEDs and other elements. To do this, the reflector was removed, for which six screws were unscrewed. On the printed circuit board there were only three LEDs, a chip (chip) in the form of a droplet, a transistor and a diode.
Five wires went from the board and battery into the handle. In order to understand their connection, it was necessary to disassemble it. To do this, use a Phillips screwdriver to unscrew the two screws inside the flashlight, which were located next to the hole into which the wires went.
To detach the flashlight handle from its body, it must be moved away from the mounting screws. This must be done carefully so as not to tear the wires off the board.
As it turned out, there were no radio-electronic elements in the pen. Two white wires were soldered to the terminals of the flashlight on/off button, and the rest to the connector for connecting the charger. A red wire was soldered to pin 1 of the connector (the numbering is conditional), the other end of which was soldered to the positive input of the printed circuit board. A blue-white conductor was soldered to the second contact, the other end of which was soldered to the negative pad of the printed circuit board. A green wire was soldered to pin 3, the second end of which was soldered to the negative terminal of the battery.
Electrical circuit diagram
Having dealt with the wires hidden in the handle, you can draw an electrical circuit diagram of the Photon flashlight.
From the negative terminal of the battery GB1, voltage is supplied to pin 3 of connector X1 and then from its pin 2 through a blue-white conductor it is supplied to the printed circuit board.
Connector X1 is designed in such a way that when the charger plug is not inserted into it, pins 2 and 3 are connected to each other. When the plug is inserted, pins 2 and 3 are disconnected. This ensures automatic disconnection of the electronic part of the circuit from the charger, eliminating the possibility of accidentally turning on the flashlight while charging the battery.
From the positive terminal of battery GB1, voltage is supplied to D1 (microcircuit-chip) and the emitter of a bipolar transistor type S8550. The CHIP performs only the function of a trigger, allowing a button to turn on or off the glow of EL LEDs (⌀8 mm, glow color - white, power 0.5 W, current consumption 100 mA, voltage drop 3 V.). When you first press the S1 button from the D1 chip, a positive voltage is applied to the base of the transistor Q1, it opens and the supply voltage is supplied to the LEDs EL1-EL3, the flashlight turns on. When you press button S1 again, the transistor closes and the flashlight turns off.
From a technical point of view, such a circuit solution is illiterate, since it increases the cost of the flashlight, reduces its reliability, and in addition, due to the voltage drop at the junction of transistor Q1, up to 20% of the battery capacity is lost. Such a circuit solution is justified if it is possible to adjust the brightness of the light beam. In this model, instead of a button, it was enough to install a mechanical switch.
It was surprising that in the circuit, LEDs EL1-EL3 are connected in parallel to the battery like incandescent light bulbs, without current-limiting elements. As a result, when turned on, a current passes through the LEDs, the magnitude of which is limited only by the internal resistance of the battery and when it is fully charged, the current may exceed the permissible value for the LEDs, which will lead to their failure.
Checking the functionality of the electrical circuit
To check the serviceability of the microcircuit, transistor and LEDs, a 4.4 V DC voltage was applied from an external power source with a current limiting function, maintaining polarity, directly to the power pins of the printed circuit board. The current limit value was set to 0.5 A.
After pressing the power button, the LEDs lit up. After pressing again, they went out. The LEDs and the microcircuit with the transistor turned out to be serviceable. All that remains is to figure out the battery and charger.
Acid battery recovery
Since the 1.7 A acid battery was completely discharged, and the standard charger was faulty, I decided to charge it from a stationary power supply. When connecting the battery for charging to a power supply with a set voltage of 9 V, the charging current was less than 1 mA. The voltage was increased to 30 V - the current increased to 5 mA, and after an hour at this voltage it was already 44 mA. Next, the voltage was reduced to 12 V, the current dropped to 7 mA. After 12 hours of charging the battery at a voltage of 12 V, the current rose to 100 mA, and the battery was charged with this current for 15 hours.
The temperature of the battery case was within normal limits, which indicated that the charging current was not used to generate heat, but to accumulate energy. After charging the battery and finalizing the circuit, which will be discussed below, tests were carried out. The flashlight with a restored battery illuminated continuously for 16 hours, after which the brightness of the beam began to decrease and therefore it was turned off.
Using the method described above, I had to repeatedly restore the functionality of deeply discharged small-sized acid batteries. As practice has shown, only serviceable batteries that have been forgotten for some time can be restored. Acid batteries that have exhausted their service life cannot be restored.
Charger repair
Measuring the voltage value with a multimeter at the contacts of the output connector of the charger showed its absence.
Judging by the sticker pasted on the adapter body, it was a power supply that outputs an unstabilized DC voltage of 12 V with a maximum load current of 0.5 A. There were no elements in the electrical circuit that limited the amount of charging current, so the question arose, why in the quality charger, did you use a regular power supply?
When the adapter was opened, a characteristic smell of burnt electrical wiring appeared, which indicated that the transformer winding had burned out.
A continuity test of the primary winding of the transformer showed that it was broken. After cutting the first layer of tape insulating the primary winding of the transformer, a thermal fuse was discovered, designed for an operating temperature of 130°C. Testing showed that both the primary winding and the thermal fuse were faulty.
Repairing the adapter was not economically feasible, since it was necessary to rewind the primary winding of the transformer and install a new thermal fuse. I replaced it with a similar one that was on hand, with a DC voltage of 9 V. The flexible cord with a connector had to be resoldered from a burnt adapter.
The photo shows a drawing of the electrical circuit of a burnt-out power supply (adapter) of the Photon LED flashlight. The replacement adapter was assembled according to the same scheme, only with an output voltage of 9 V. This voltage is quite sufficient to provide the required battery charging current with a voltage of 4.4 V.
Just for fun, I connected the flashlight to a new power supply and measured the charging current. Its value was 620 mA, and this was at a voltage of 9 V. At a voltage of 12 V, the current was about 900 mA, significantly exceeding the load capacity of the adapter and the recommended battery charging current. For this reason, the primary winding of the transformer burned out due to overheating.
Finalization of the electrical circuit diagram
LED rechargeable flashlight "Photon"
To eliminate circuit violations in order to ensure reliable and long-term operation, changes were made to the flashlight circuit and the printed circuit board was modified.
The photo shows the electrical circuit diagram of the converted Photon LED flashlight. Additional installed radio elements are shown in blue. Resistor R2 limits the battery charging current to 120 mA. To increase the charging current, you need to reduce the resistor value. Resistors R3-R5 limit and equalize the current flowing through the LEDs EL1-EL3 when the flashlight is illuminated. The EL4 LED with a series-connected current-limiting resistor R1 is installed to indicate the battery charging process, since the developers of the flashlight did not take care of this.
To install current-limiting resistors on the board, the printed traces were cut, as shown in the photo. The charge current-limiting resistor R2 was soldered at one end to the contact pad, to which the positive wire coming from the charger had previously been soldered, and the soldered wire was soldered to the second terminal of the resistor. An additional wire (yellow in the photo) was soldered to the same contact pad, intended to connect the battery charging indicator.
Resistor R1 and indicator LED EL4 were placed in the flashlight handle, next to the connector for connecting the charger X1. The LED anode pin was soldered to pin 1 of connector X1, and a current-limiting resistor R1 was soldered to the second pin, the cathode of the LED. A wire (yellow in the photo) was soldered to the second terminal of the resistor, connecting it to the terminal of resistor R2, soldered to the printed circuit board. Resistor R2, for ease of installation, could have been placed in the flashlight handle, but since it heats up when charging, I decided to place it in a freer space.
When finalizing the circuit, MLT type resistors with a power of 0.25 W were used, except for R2, which is designed for 0.5 W. The EL4 LED is suitable for any type and color of light.
This photo shows the charging indicator while the battery is charging. Installing an indicator made it possible not only to monitor the battery charging process, but also to monitor the presence of voltage in the network, the health of the power supply and the reliability of its connection.
How to replace a burnt out CHIP
If suddenly a CHIP - a specialized unmarked microcircuit in a Photon LED flashlight, or a similar one assembled according to a similar circuit - fails, then to restore the flashlight's functionality it can be successfully replaced with a mechanical switch.
To do this, you need to remove the D1 chip from the board, and instead of the Q1 transistor switch, connect an ordinary mechanical switch, as shown in the above electrical diagram. The switch on the flashlight body can be installed instead of the S1 button or in any other suitable place.
Repair and alteration of LED flashlight
14Led Smartbuy Colorado
The Smartbuy Colorado LED flashlight stopped turning on, although three new AAA batteries were installed.
The waterproof body was made of anodized aluminum alloy and had a length of 12 cm. The flashlight looked stylish and was easy to use.
How to check batteries for suitability in an LED flashlight
Repair of any electrical device begins with checking the power source, therefore, despite the fact that new batteries were installed in the flashlight, repairs should begin with checking them. In the Smartbuy flashlight, the batteries are installed in a special container, in which they are connected in series using jumpers. In order to gain access to the flashlight batteries, you need to disassemble it by rotating the back cover counterclockwise.
Batteries must be installed in the container, observing the polarity indicated on it. The polarity is also indicated on the container, so it must be inserted into the flashlight body with the side on which the “+” sign is marked.
First of all, it is necessary to visually check all contacts of the container. If there are traces of oxides on them, then the contacts must be cleaned to a shine using sandpaper or the oxide must be scraped off with a knife blade. To prevent re-oxidation of the contacts, they can be lubricated with a thin layer of any machine oil.
Next you need to check the suitability of the batteries. To do this, touching the probes of a multimeter turned on in DC voltage measurement mode, you need to measure the voltage at the contacts of the container. Three batteries are connected in series and each of them should produce a voltage of 1.5 V, therefore the voltage at the terminals of the container should be 4.5 V.
If the voltage is less than specified, then it is necessary to check the correct polarity of the batteries in the container and measure the voltage of each of them individually. Perhaps only one of them sat down.
If everything is in order with the batteries, then you need to insert the container into the flashlight body, observing the polarity, screw on the cap and check its functionality. In this case, you need to pay attention to the spring in the cover, through which the supply voltage is transmitted to the flashlight body and from it directly to the LEDs. There should be no traces of corrosion on its end.
How to check if the switch is working properly
If the batteries are good and the contacts are clean, but the LEDs do not light, then you need to check the switch.
The Smartbuy Colorado flashlight has a sealed push-button switch with two fixed positions, closing the wire coming from the positive terminal of the battery container. When you press the switch button for the first time, its contacts close, and when you press it again, they open.
Since the flashlight contains batteries, you can also check the switch using a multimeter turned on in voltmeter mode. To do this, you need to rotate it counterclockwise, if you look at the LEDs, unscrew its front part and put it aside. Next, touch the body of the flashlight with one multimeter probe, and with the second touch the contact, which is located deep in the center of the plastic part shown in the photo.
The voltmeter should show a voltage of 4.5 V. If there is no voltage, press the switch button. If it is working properly, then voltage will appear. Otherwise, the switch needs to be repaired.
Checking the health of the LEDs
If the previous search steps failed to detect a fault, then at the next stage you need to check the reliability of the contacts supplying the supply voltage to the board with LEDs, the reliability of their soldering and serviceability.
A printed circuit board with LEDs sealed into it is fixed in the head of the flashlight using a steel spring-loaded ring, through which the supply voltage from the negative terminal of the battery container is simultaneously supplied to the LEDs along the flashlight body. The photo shows the ring from the side it presses against the printed circuit board.
The retaining ring is fixed quite tightly, and it was only possible to remove it using the device shown in the photo. You can bend such a hook from a steel strip with your own hands.
After removing the retaining ring, the printed circuit board with LEDs, which is shown in the photo, was easily removed from the head of the flashlight. The absence of current-limiting resistors immediately caught my eye; all 14 LEDs were connected in parallel and directly to the batteries via a switch. Connecting LEDs directly to a battery is unacceptable, since the amount of current flowing through the LEDs is limited only by the internal resistance of the batteries and can damage the LEDs. At best, it will greatly reduce their service life.
Since all the LEDs in the flashlight were connected in parallel, it was not possible to check them with a multimeter turned on in resistance measurement mode. Therefore, the printed circuit board was supplied with a DC supply voltage from an external source of 4.5 V with a current limit of 200 mA. All LEDs lit up. It became obvious that the problem with the flashlight was poor contact between the printed circuit board and the retaining ring.
Current consumption of LED flashlight
For fun, I measured the current consumption of LEDs from batteries when they were turned on without a current-limiting resistor.
The current was more than 627 mA. The flashlight is equipped with LEDs of type HL-508H, the operating current of which should not exceed 20 mA. 14 LEDs are connected in parallel, therefore, the total current consumption should not exceed 280 mA. Thus, the current flowing through the LEDs more than doubled the rated current.
Such a forced mode of LED operation is unacceptable, as it leads to overheating of the crystal, and as a result, premature failure of the LEDs. An additional disadvantage is that the batteries drain quickly. They will be enough, if the LEDs do not burn out first, for no more than an hour of operation.
The design of the flashlight did not allow soldering current-limiting resistors in series with each LED, so we had to install one common one for all LEDs. The resistor value had to be determined experimentally. To do this, the flashlight was powered by pants batteries and an ammeter was connected to the gap in the positive wire in series with a 5.1 Ohm resistor. The current was about 200 mA. When installing an 8.2 Ohm resistor, the current consumption was 160 mA, which, as tests showed, is quite sufficient for good lighting at a distance of at least 5 meters. The resistor did not get hot to the touch, so any power will do.
Redesign of the structure
After the study, it became obvious that for reliable and durable operation of the flashlight, it is necessary to additionally install a current-limiting resistor and duplicate the connection of the printed circuit board with the LEDs and the fixing ring with an additional conductor.
If previously it was necessary for the negative bus of the printed circuit board to touch the body of the flashlight, then due to the installation of the resistor, it was necessary to eliminate the contact. To do this, a corner was ground off from the printed circuit board along its entire circumference, from the side of the current-carrying paths, using a needle file.
To prevent the clamping ring from touching the current-carrying tracks when fixing the printed circuit board, four rubber insulators about two millimeters thick were glued onto it with Moment glue, as shown in the photograph. Insulators can be made from any dielectric material, such as plastic or thick cardboard.
The resistor was pre-soldered to the clamping ring, and a piece of wire was soldered to the outermost track of the printed circuit board. An insulating tube was placed over the conductor, and then the wire was soldered to the second terminal of the resistor.
After simply upgrading the flashlight with your own hands, it began to turn on stably and the light beam illuminated objects well at a distance of more than eight meters. Additionally, the battery life has more than tripled, and the reliability of the LEDs has increased many times over.
An analysis of the causes of failure of repaired Chinese LED lights showed that they all failed due to poorly designed electrical circuits. It remains only to find out whether this was done intentionally in order to save on components and shorten the life of the flashlights (so that more people would buy new ones), or as a result of the illiteracy of the developers. I am inclined to the first assumption.
Repair of LED flashlight RED 110
A flashlight with a built-in acid battery from the Chinese manufacturer RED brand was repaired. The flashlight had two emitters: one with a beam in the form of a narrow beam and one emitting diffused light.
The photo shows the appearance of the RED 110 flashlight. I immediately liked the flashlight. Convenient body shape, two operating modes, a loop for hanging around the neck, a retractable plug for connecting to the mains for charging. In the flashlight, the diffused light LED section was shining, but the narrow beam was not.
To make the repair, we first unscrewed the black ring securing the reflector, and then unscrewed one self-tapping screw in the hinge area. The case easily separated into two halves. All parts were secured with self-tapping screws and were easily removed.
The charger circuit was made according to the classical scheme. From the network, through a current-limiting capacitor with a capacity of 1 μF, voltage was supplied to a rectifier bridge of four diodes and then to the battery terminals. The voltage from the battery to the narrow beam LED was supplied through a 460 Ohm current-limiting resistor.
All parts were mounted on a single-sided printed circuit board. The wires were soldered directly to the contact pads. The appearance of the printed circuit board is shown in the photograph.
10 side light LEDs were connected in parallel. The supply voltage was supplied to them through a common current-limiting resistor 3R3 (3.3 Ohms), although according to the rules, a separate resistor must be installed for each LED.
During an external inspection of the narrow beam LED, no defects were found. When power was supplied through the flashlight switch from the battery, voltage was present at the LED terminals, and it heated up. It became obvious that the crystal was broken, and this was confirmed by a continuity test with a multimeter. The resistance was 46 ohms for any connection of the probes to the LED terminals. The LED was faulty and needed to be replaced.
For ease of operation, the wires were unsoldered from the LED board. After freeing the LED leads from the solder, it turned out that the LED was tightly held by the entire plane of the reverse side on the printed circuit board. To separate it, we had to fix the board in the desktop temples. Next, place the sharp end of the knife at the junction of the LED and the board and lightly hit the knife handle with a hammer. The LED bounced off.
As usual, there were no markings on the LED housing. Therefore, it was necessary to determine its parameters and select a suitable replacement. Based on the overall dimensions of the LED, the battery voltage and the size of the current-limiting resistor, it was determined that a 1 W LED (current 350 mA, voltage drop 3 V) would be suitable for replacement. From the “Reference Table of Parameters of Popular SMD LEDs,” a white LED6000Am1W-A120 LED was selected for repair.
The printed circuit board on which the LED is installed is made of aluminum and at the same time serves to remove heat from the LED. Therefore, when installing it, it is necessary to ensure good thermal contact due to the tight fit of the rear plane of the LED to the printed circuit board. To do this, before sealing, thermal paste was applied to the contact areas of the surfaces, which is used when installing a radiator on a computer processor.
In order to ensure a tight fit of the LED plane to the board, you must first place it on the plane and slightly bend the leads upward so that they deviate from the plane by 0.5 mm. Next, tin the terminals with solder, apply thermal paste and install the LED on the board. Next, press it to the board (it’s convenient to do this with a screwdriver with the bit removed) and warm up the leads with a soldering iron. Next, remove the screwdriver, press it with a knife at the bend of the lead to the board and heat it with a soldering iron. After the solder has hardened, remove the knife. Due to the spring properties of the leads, the LED will be pressed tightly to the board.
When installing the LED, polarity must be observed. True, in this case, if a mistake is made, it will be possible to swap the voltage supply wires. The LED is soldered and you can check its operation and measure the current consumption and voltage drop.
The current flowing through the LED was 250 mA, the voltage drop was 3.2 V. Hence the power consumption (you need to multiply the current by the voltage) was 0.8 W. It was possible to increase the operating current of the LED by decreasing the resistance to 460 Ohms, but I did not do this, since the brightness of the glow was sufficient. But the LED will operate in a lighter mode, heat up less, and the flashlight’s operating time on a single charge will increase.
Checking the heating of the LED after operating for an hour showed effective heat dissipation. It heated up to a temperature of no more than 45°C. Sea trials showed a sufficient illumination range in the dark, more than 30 meters.
Replacing a lead acid battery in an LED flashlight
A failed acid battery in an LED flashlight can be replaced with either a similar acid battery or a lithium-ion (Li-ion) or nickel-metal hydride (Ni-MH) AA or AAA battery.
The Chinese lanterns being repaired were equipped with lead-acid AGM batteries of various sizes without markings with a voltage of 3.6 V. According to calculations, the capacity of these batteries ranges from 1.2 to 2 A×hours.
On sale you can find a similar acid battery from a Russian manufacturer for the 4V 1Ah Delta DT 401 UPS, which has an output voltage of 4 V with a capacity of 1 Ah, costing a couple of dollars. To replace it, simply re-solder the two wires, observing the polarity.
When choosing or assembling a new LED flashlight, be sure to pay attention to the LED used. If the only task of the future flashlight is to illuminate a dark entrance, then almost any bright white LED will cope with this task. Another thing is the desire to get a portable lighting device with parameters for a more complex task. In this case, the luminous flux is of particular importance, that is, the ability of the flashlight to produce a sufficiently powerful beam and illuminate a wide area of space.
Which LED brands are in the top positions, and what characteristics do their light-emitting diodes used in flashlights have?
Main characteristics
The quality of light emitted by the flashlight is controlled by the LED, which can be called, without exaggeration, the heart of the device. The stability of a flashlight's heart rate depends on many parameters, the main ones being current consumption, luminous flux and color temperature. The trendsetter is considered to be the Cree company, which produces a wide line of super-bright and powerful LEDs, including for flashlights. Modern flashlights are designed with a single LED with a power of 1, 2, or 3 W. In the one-watt version, the forward current is about 350 mA with a voltage drop of 2.8-2.9 V.
The current and voltage of a two-watt LED is about 700 mA and 3.0 V, respectively, and a similar 3 W crystal consumes approximately 1000 mA and 3.2 V. The electrical indicators given are typical for LED models of the world's leading brands.
The radiation intensity, also called luminous flux, depends on the manufacturer and family of the LED. The rated value of the luminous flux of high-power LEDs is usually measured at the maximum permissible operating current. The manufacturer of branded flashlights, along with the type of LED installed, indicates the number of lumens produced by the product.
Unfortunately, flashlight packaging often indicates inflated characteristics, including luminous flux. The reason for this is simple - any manufacturer wants to sell as much product as possible.
Luminous flux is inextricably linked with light. Modern light-emitting diodes are capable of emitting a luminous flux of up to 200 lumens per 1 watt and can be produced with any glow temperature: from yellowish warm to cool white. Lanterns with a warm white emission color (T≤3500°K) are the most pleasing to the eye, but less bright. Lighting with a neutral color temperature (T=4000-5500°K) allows you to view fine details more effectively. Cool white beam (T≥6500°K) in powerful flashlights with a long illumination range, but irritates the eyes during prolonged use. 
Due to the impossibility of making accurate calculations, the lifespan of LEDs is calculated by extrapolation. At a temperature of 25-50 °C, their crystal service life can exceed 200 thousand hours, but this is not economically justified. Therefore, manufacturers allow the operating temperature to increase to 85°C, thus saving on cooling costs. Exceeding the threshold of 150°C leads to irreversible processes of crystal burnout and loss of brightness.
Color rendering index (CRI) is a qualitative indicator characterizing the ability of an LED to illuminate objects without distorting their real color. For LED lighting sources, including flashlights, a color rendering index of 75 CRI or higher is considered good.
An important element of an LED is the lens. It sets the angle of dispersion of the light flux, and therefore determines the range of the beam. The technical characteristics of LEDs must indicate the value of the radiation angle. For each model, this parameter is individual and can vary from 20 to 240 degrees. Powerful LEDs for flashlights have an angle of 90-120° and, as a rule, are equipped with a reflector with an additional lens in the housing.
Despite the sharp leap in the development of high-power multi-chip LEDs, world leaders continue to produce less powerful LEDs. They are produced in small cases, not exceeding 10 mm in width or diameter. The typical current value of such light-emitting diodes does not exceed 70 mA, and the luminous flux is 50 lm. Powerful flashlights based on them are gradually disappearing from store shelves due to worse technical characteristics and the need for series-parallel connection to increase brightness. Compared to one powerful crystal, the reliability of the circuit and the dispersion angle of several such elements in one package are much worse.
Separately, it is worth noting the four-pin LEDs in the P4 “SuperFlux” or “Piranha” package, which have improved technical characteristics. Piranha LEDs have two important advantages that make them in demand:
- distribute the light flux more evenly;
- do not require heat removal;
- have low cost.
5 largest manufacturers
A portable flashlight must not only be ergonomic, but also be equipped with a reliable LED source with a high working life without loss of brightness. In order not to make a mistake with your choice, preference should be given to world-class manufacturers of LED products.
A division of the Japanese company Nichia has long held a leading position in the production of LEDs of all types. Due to the high cost of products and increasing competition from China and Taiwan, today it is becoming increasingly rare to find their LEDs in flashlights on the European market. However, the world needs Nichia as an engine of progress. After all, the developments of Japanese companies are taken as a basis by their Chinese and Taiwanese colleagues. 
Powerful LEDs for flashlights from the world-famous company Cree hold the lead not only on the American continent. Standing out due to their lower cost and high quality, LEDs from Cree are available to everyone on the European continent. A rechargeable flashlight with a powerful crystal from an American brand is a reliable friend on a hike, night fishing, etc. 
Philips Lumileds is a European manufacturer of wide-spectrum light-emitting diodes. The company has achieved certain progress in the construction of outdoor lighting systems of functional and architectural significance. Philips Lumileds developers take an integrated approach to building LED systems, taking into account their design, degree of protection and ease of use. 
The South Korean corporation Samsung, well known in Russia, promptly financed its division to search for new LED solutions and now has a full production cycle of emitting diodes. Samsung is not limited to producing LED backlights for its own displays. Their successes have spread to other market segments: high-power LEDs (including for flashlights), ultra-bright flash elements, as well as indoor and outdoor lighting modules. 
Osram Opto Semiconductors has become famous for the excellent characteristics of LEDs from the Duris series, which are distinguished by their high luminous efficiency and color rendering index. The German company has relied on the introduction of LED technologies into industrial sectors, focusing on the production of ready-made specialized lamps and fixtures. Osram laboratories improve the performance of light-emitting diodes not only in the visible spectrum, but also make discoveries in the IR, UV and laser directions. 
Scientific reports coupled with news about the development of artificial lighting indicate continued healthy competition between large corporations. We see positive trends in the development of LED technology in the constantly updated range of flashlights, surprising with their long-range beam, high degree of protection, ability to charge from solar energy and other know-how.
Read also
The repaired lead-acid battery from the LED flashlight (by adding distilled water and initial intensive charging) worked for almost six months after that. He considered further attempts to resuscitate him inappropriate and began to look for some other battery, taking into account voltage, capacity and possibly permissible dimensions.
Given the current abundance, it seemed that there should be no difficulty in selecting a new battery. But everything didn’t suit me. The most desirable option - a battery from a mobile phone, did not fit in size. And those that were suitable in size had a very inappropriate price.
Quite by accident I noticed a battery compartment for four AAA batteries (or batteries). I tried to place it inside the flashlight - it worked. And in general, according to all possible and even expected parameters, it turned out that this was exactly what was needed. If you want, install AAA batteries of 1.2 volts, or you can use dead batteries, which can then be recharged once or twice.
Flashlight connection diagram
The lantern had the following electrical circuit from the manufacturer. Initially I didn’t touch it, but now I’ll have to change it in accordance with the intended method of operation. Moreover, initially the modification is supposed to be carried out in a budget format and without observing the circuit design bells and whistles proposed in such cases. To do this, you need to decide on the LEDs available in the flashlight (their voltage, current consumption?). There are two ways:
- practical(with measurements)
- theoretical(search in the table with a comparison of sizes, configurations, and other distinctive features). I chose the second one.
In general, there is a useful article for this, which I advise you to read. Headlight LEDs, operating voltage 2.9 - 3.3 volts, maximum permissible current consumption 20 milliamps.
Side panel LEDs, operating voltage, 3.0 - 3.5 volts, maximum permissible current consumption 20 milliamps.
I connected the headlight through a constant resistor with a resistance of 2 Ohms and a trimming resistor of 0.5-20 Ohms, with which I set the permissible current to three parallel-connected LEDs at 60 mA.
I did the same with the side panel, only the constant resistance here is 33 Ohms, and with the trimmer I set the total current of the LEDs to 40 mA.
Refinement scheme
The electrical circuit took this form based on the desired operating mode, which is that for any resistance set on the trimmer resistor, the light output of the headlight will have a ratio with the light output of the side panel as 3:2. That is, the headlight light will always be a third stronger.
Everything fits. The battery fits into the case without effort, but there is no freedom of movement in it either. A suitable “niche” was found for the general, headlight and side panel, trimming resistor.
It is also accessible when the lamp is assembled, so that if necessary, you can always make the appropriate adjustments.
Video
At the time of filming, unfortunately there was no more spacious dark room than the bathroom, but please take into account my assurances that the flashlight’s headlight works perfectly at a distance of 10 meters or even more. Author of the project - Babay iz Barnaula.
Discuss the article REPLACEMENT OF LEAD BATTERIES IN FLASHLIGHTS
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!
