How to repair an LED flashlight? Do-it-yourself repair and modernization of Lentel, Photon, Smartbuy Colorado and RED LED lights Electrical circuit diagram
As you can see, the scheme is simple. Main elements: current-limiting capacitor, rectifier diode bridge with four diodes, battery, switch, super-bright LEDs, LED to indicate flashlight battery charging.
Well, now, in order, about the purpose of all the elements in the flashlight.
Current limiting capacitor. It is designed to limit the battery charging current. Its capacity for each type of flashlight may be different. A non-polar mica capacitor is used. The operating voltage must be at least 250 volts. In the circuit it must be bypassed, as shown, with a resistor. It serves to discharge the capacitor after you remove the flashlight from the charging outlet. Otherwise, you may get an electric shock if you accidentally touch the 220 volt power terminals of the flashlight. The resistance of this resistor must be at least 500 kOhm.
The rectifier bridge is assembled on silicon diodes with a reverse voltage of at least 300 volts.
To indicate the charging of the flashlight battery, a simple red or green LED is used. It is connected in parallel to one of the diodes of the rectifier bridge. True, in the diagram I forgot to indicate the resistor connected in series with this LED.
It makes no sense to talk about the other elements; everything should be clear anyway.
I would like to draw your attention to the main points of repairing an LED flashlight. Let's look at the main faults and how to fix them.
1. The flashlight stopped shining. There aren't many options here. The reason may be the failure of super-bright LEDs. This can happen, for example, in the following case. You put the flashlight on charge and accidentally turned on the switch. In this case, a sharp jump in current will occur and one or more diodes of the rectifier bridge may be broken. And behind them, the capacitor may not be able to withstand it and will short out. The voltage on the battery will increase sharply and the LEDs will fail. So, under no circumstances turn on the flashlight while charging unless you want to throw it away.
2. The flashlight does not turn on. Well, here you need to check the switch.
3. The flashlight discharges very quickly. If your flashlight is “experienced”, then most likely the battery has reached the end of its service life. If you actively use the flashlight, then after one year of use the battery will no longer last.
Problem 1: The LED flashlight does not turn on or flickers when working
As a rule, this is the cause of poor contact. The easiest way to treat it is to tighten all the threads tightly.
If the flashlight doesn't work at all, start by checking the battery. It may be discharged or damaged.
Unscrew the back cover of the flashlight and use a screwdriver to connect the housing to the negative terminal of the battery. If the flashlight lights up, then the problem is in the module with the button.
90% of the buttons of all LED lights are made according to the same scheme:
The button body is made of aluminum with a thread, a rubber cap is inserted there, then the button module itself and a pressure ring for contact with the body.
The problem is most often solved by a loose clamping ring.
To fix this problem, just find round pliers with thin tips or thin scissors that need to be inserted into the holes, as in the photo, and turned clockwise.
If the ring moves, the problem is fixed. If the ring stays in place, then the problem lies in the contact of the button module with the body. Unscrew the clamping ring counterclockwise and pull the button module out.
Poor contact often occurs due to oxidation of the aluminum surface of the ring or border on the printed circuit board (indicated by arrows)
Simply wipe these surfaces with alcohol and functionality will be restored.
Button modules are different. Some have contact through the printed circuit board, others have contact through the side petals to the flashlight body.
Just bend this petal to the side so that the contact is tighter.
Alternatively, you can make a solder from tin so that the surface is thicker and the contact is pressed better.
All LED lights are basically the same
The plus goes through the positive contact of the battery to the center of the LED module.
The negative goes through the body and is closed with a button.
It would be a good idea to check the tightness of the LED module inside the housing. This is also a common problem with LED lights.
Using round nose pliers or pliers, rotate the module clockwise until it stops. Be careful, it is easy to damage the LED at this point.
These actions should be quite enough to restore the functionality of the LED flashlight.
It’s worse when the flashlight works and the modes are switched, but the beam is very dim, or the flashlight doesn’t work at all and there’s a burning smell inside.
Problem 2. The flashlight works fine, but it’s dim or doesn’t work at all and there’s a burning smell inside
Most likely the driver has failed.
The driver is an electronic circuit on transistors that controls the flashlight modes and is also responsible for a constant voltage level, regardless of battery discharge.
You need to unsolder the burnt driver and solder in a new driver, or connect the LED directly to the battery. In this case, you lose all modes and are left only with the maximum one.
Sometimes (much less often) the LED fails.
You can check this very simply. Apply a voltage of 4.2 V/ to the contact pads of the LED. The main thing is not to confuse the polarity. If the LED lights up brightly, then the driver has failed, if vice versa, then you need to order a new LED.
Unscrew the module with the LED from the housing.
Modules vary, but as a rule, they are made of copper or brass and
The most weakness Similar lanterns have a button. Its contacts oxidize, as a result of which the flashlight begins to shine dimly, and then may stop turning on altogether.
The first sign is that a flashlight with a normal battery shines dimly, but if you click the button several times, the brightness increases.
The easiest way to make such a lantern shine is to do the following:
1. Take a thin stranded wire and cut off one strand.
2. We wind the wires onto the spring.
3. We bend the wire so that the battery does not break it. The wire should protrude slightly
above the twisting part of the flashlight.
4. Twist tightly. We break off (tear off) the excess wire.
As a result, the wire provides good contact with the negative part of the battery and the flashlight
will shine with proper brightness. Of course, the button is no longer available for such repairs, so
Turning on and off the flashlight is done by turning the head part.
My Chinese guy worked like this for a couple of months. If you need to change the battery, the back of the flashlight
should not be touched. We turn our heads away.
RESTORING THE OPERATION OF THE BUTTON.
Today I decided to bring the button back to life. The button is located in a plastic case, which
It's just pressed into the back of the light. In principle, it can be pushed back, but I did it a little differently:
1. Use a 2 mm drill to make a couple of holes to a depth of 2-3 mm.
2. Now you can use tweezers to unscrew the housing with the button.
3. Remove the button.
4. The button is assembled without glue or latches, so it can be easily disassembled with a stationery knife.
The photo shows that the moving contact has oxidized (a round thing in the center that looks like a button).
You can clean it with an eraser or fine sandpaper and put the button back together, but I decided to additionally tin both this part and the fixed contacts.
1. Clean with fine sandpaper.
2. Apply a thin layer to the areas marked in red. We wipe off the flux with alcohol,
assembling the button.
3. To increase reliability, I soldered a spring to the bottom contact of the button.
4. Putting everything back together.
After repair, the button works perfectly. Of course, tin also oxidizes, but since tin is a fairly soft metal, I hope that the oxide film will be
easy to break down. It’s not for nothing that the central contact on light bulbs is made of tin.
IMPROVING FOCUS.
My Chinese had a very vague idea of what a “hotspot” was, so I decided to enlighten him.
Unscrew the head part.
1. There is a small hole in the board (arrow). Use an awl to twist out the filling.
At the same time, lightly press your finger on the glass from the outside. This makes it easier to unscrew.
2. Remove the reflector.
3. Take ordinary office paper and punch 6-8 holes with an office hole punch.
The diameter of the holes in the hole punch matches perfectly with the diameter of the LED.
Cut out 6-8 paper washers.
4. Place the washers on the LED and press it with the reflector.
Here you will have to experiment with the number of washers. I improved the focusing of a couple of flashlights in this way; the number of washers was in the range of 4-6. The current patient required 6 of them.
INCREASE THE BRIGHTNESS (for those who know a little about electronics).
The Chinese save on everything. A couple of extra details will increase the cost, so they don’t install it.
The main part of the diagram (marked in green) may be different. On one or two transistors or on a specialized microcircuit (I have a circuit of two parts:
inductor and a 3-leg IC similar to a transistor). But they save on the part marked in red. I added a capacitor and a pair of 1n4148 diodes in parallel (I didn't have any shots). The brightness of the LED increased by 10-15 percent.
1. This is what the LED looks like in similar Chinese ones. From the side you can see that there are thick and thin legs inside. The thin leg is a plus. You need to be guided by this sign, because the colors of the wires can be completely unpredictable.
2. This is what the board looks like with the LED soldered to it (on the back side). Green color indicates foil. The wires coming from the driver are soldered to the legs of the LED.
3. Using a sharp knife or a triangular file, cut the foil on the positive side of the LED.
We sand the entire board to remove the varnish.
4. Solder the diodes and capacitor. I took the diodes from a broken one computer unit power supply, the tantalum capacitor fell out of some burnt-out hard drive.
The positive wire now needs to be soldered to the pad with the diodes.
As a result, the flashlight produces (by eye) 10-12 lumens (see photo with hotspots),
judging by the Phoenix, which produces 9 lumens in minimum mode.
Many people have various Chinese lanterns that run on a single battery. Something like this:
Unfortunately, they are very short-lived. I will tell you further about how to bring a flashlight back to life and about some simple modifications that can improve such flashlights.
The weakest point of such flashlights is the button. Its contacts oxidize, as a result of which the flashlight begins to shine dimly, and then may stop turning on altogether.
The first sign is that a flashlight with a normal battery shines dimly, but if you click the button several times, the brightness increases.
The easiest way to make such a lantern shine is to do the following: 
1. Take a thin stranded wire and cut off one strand.
2. We wind the wires onto the spring.
3. We bend the wire so that the battery does not break it. The wire should protrude slightly
above the twisting part of the flashlight.
4. Twist tightly. We break off (tear off) the excess wire.
As a result, the wire provides good contact with the negative part of the battery and the flashlight
will shine with proper brightness. Of course, the button is no longer available for such repairs, so
Turning the flashlight on and off is done by turning the head part.
My Chinese guy worked like this for a couple of months. If you need to change the battery, the back of the flashlight
should not be touched. We turn our heads away.
RESTORING THE OPERATION OF THE BUTTON.
Today I decided to bring the button back to life. The button is located in a plastic case, which
It's just pressed into the back of the light. In principle, it can be pushed back, but I did it a little differently: 
1. Use a 2 mm drill to make a couple of holes to a depth of 2-3 mm.
2. Now you can use tweezers to unscrew the housing with the button.
3. Remove the button.
4. The button is assembled without glue or latches, so it can be easily disassembled with a stationery knife.
The photo shows that the moving contact has oxidized (a round thing in the center that looks like a button).
You can clean it with an eraser or fine sandpaper and put the button back together, but I decided to additionally tin both this part and the fixed contacts. 
1. Clean with fine sandpaper.
2. Apply a thin layer to the areas marked in red. We wipe off the flux with alcohol,
assembling the button.
3. To increase reliability, I soldered a spring to the bottom contact of the button.
4. Putting everything back together.
After repair, the button works perfectly. Of course, tin also oxidizes, but since tin is a fairly soft metal, I hope that the oxide film will be
easy to break down. It’s not for nothing that the central contact on light bulbs is made of tin.
IMPROVING FOCUS.
My Chinese had a very vague idea of what a “hotspot” was, so I decided to enlighten him.
Unscrew the head part. 
1. There is a small hole in the board (arrow). Use an awl to twist out the filling.
At the same time, lightly press your finger on the glass from the outside. This makes it easier to unscrew.
2. Remove the reflector.
3. Take ordinary office paper and punch 6-8 holes with an office hole punch.
The diameter of the holes in the hole punch matches perfectly with the diameter of the LED.
Cut out 6-8 paper washers.
4. Place the washers on the LED and press it with the reflector.
Here you will have to experiment with the number of washers. I improved the focusing of a couple of flashlights in this way; the number of washers was in the range of 4-6. The current patient required 6 of them.
What happened in the end: 
On the left is our Chinese, on the right is Fenix LD 10 (at minimum).
The result is quite pleasant. The hotspot became pronounced and uniform.
INCREASE THE BRIGHTNESS (for those who know a little about electronics).
The Chinese save on everything. A couple of extra details will increase the cost, so they don’t install it. 
The main part of the diagram (marked in green) may be different. On one or two transistors or on a specialized microcircuit (I have a circuit of two parts:
inductor and a 3-leg IC similar to a transistor). But they save money on the part marked in red. I added a capacitor and a pair of 1n4148 diodes in parallel (I didn't have any shots). The brightness of the LED increased by 10-15 percent.
1. This is what the LED looks like in similar Chinese ones. From the side you can see that there are thick and thin legs inside. The thin leg is a plus. You need to be guided by this sign, because the colors of the wires can be completely unpredictable.
2. This is what the board looks like with the LED soldered to it (on the back side). Green color indicates foil. The wires coming from the driver are soldered to the legs of the LED.
3. Using a sharp knife or a triangular file, cut the foil on the positive side of the LED.
We sand the entire board to remove the varnish.
4. Solder the diodes and capacitor. I took the diodes from a broken computer power supply, and soldered the tantalum capacitor from some burnt-out hard drive.
The positive wire now needs to be soldered to the pad with the diodes.
As a result, the flashlight produces (by eye) 10-12 lumens (see photo with hotspots),
judging by the Phoenix, which produces 9 lumens in minimum mode.
And the last thing: the advantage of the Chinese over the branded flashlight (yes, don’t laugh)
Branded flashlights are designed to use batteries, so
With the battery discharged to 1 volt, my Fenix LD 10 simply does not turn on. At all.
I took a dead alkaline battery that had expired in the computer mouse. The multimeter showed that it had dropped to 1.12v. The mouse no longer worked on it, Fenix, as I said, did not start. But the Chinese one works! 
On the left is the Chinese one, on the right is the Fenix LD 10 at minimum (9 lumens). Unfortunately, the white balance is off.
The phoenix has a temperature of 4200K. The Chinese is blue, but not as bad as in the photo.
Just for fun, I tried to finish off the battery. At this brightness level (5-6 lumens by eye), the flashlight worked for about 3 hours. The brightness is quite enough to illuminate your feet in a dark entrance/forest/basement. Then for another 2 hours the brightness decreased to the “firefly” level. Agree, 3-4 hours with acceptable light can solve a lot.
For this, let me take my leave.
Stari4ok.
Z.Y. The article is not a copy-paste. Made in I, especially for “NOT PROPAD”!
As you can see, the scheme is simple. Main elements: current-limiting capacitor, rectifier diode bridge with four diodes, battery, switch, super-bright LEDs, LED to indicate flashlight battery charging.
Well, now, in order, about the purpose of all the elements in the flashlight.
Current limiting capacitor. It is designed to limit the battery charging current. Its capacity for each type of flashlight may be different. A non-polar mica capacitor is used. The operating voltage must be at least 250 volts. In the circuit it must be bypassed, as shown, with a resistor. It serves to discharge the capacitor after you remove the flashlight from the charging outlet. Otherwise, you may get an electric shock if you accidentally touch the 220 volt power terminals of the flashlight. The resistance of this resistor must be at least 500 kOhm.
The rectifier bridge is assembled on silicon diodes with a reverse voltage of at least 300 volts.
To indicate the charging of the flashlight battery, a simple red or green LED is used. It is connected in parallel to one of the diodes of the rectifier bridge. True, in the diagram I forgot to indicate the resistor connected in series with this LED.
It makes no sense to talk about the other elements; everything should be clear anyway.
I would like to draw your attention to the main points of repairing an LED flashlight. Let's look at the main faults and how to fix them.
1. The flashlight stopped shining. There aren't many options here. The reason may be the failure of super-bright LEDs. This can happen, for example, in the following case. You put the flashlight on charge and accidentally turned on the switch. In this case, a sharp jump in current will occur and one or more diodes of the rectifier bridge may be broken. And behind them, the capacitor may not be able to withstand it and will short out. The voltage on the battery will increase sharply and the LEDs will fail. So, under no circumstances turn on the flashlight while charging unless you want to throw it away.
2. The flashlight does not turn on. Well, here you need to check the switch.
3. The flashlight discharges very quickly. If your flashlight is “experienced”, then most likely the battery has reached the end of its service life. If you actively use the flashlight, then after one year of use the battery will no longer last.
Problem 1: The LED flashlight does not turn on or flickers when working
As a rule, this is the cause of poor contact. The easiest way to treat it is to tighten all the threads tightly.
If the flashlight doesn't work at all, start by checking the battery. It may be discharged or damaged.
Unscrew the back cover of the flashlight and use a screwdriver to connect the housing to the negative terminal of the battery. If the flashlight lights up, then the problem is in the module with the button.
90% of the buttons of all LED lights are made according to the same scheme:
The button body is made of aluminum with a thread, a rubber cap is inserted there, then the button module itself and a pressure ring for contact with the body.
The problem is most often solved by a loose clamping ring.
To fix this problem, just find round pliers with thin tips or thin scissors that need to be inserted into the holes, as in the photo, and turned clockwise.
If the ring moves, the problem is fixed. If the ring stays in place, then the problem lies in the contact of the button module with the body. Unscrew the clamping ring counterclockwise and pull the button module out.
Poor contact often occurs due to oxidation of the aluminum surface of the ring or border on the printed circuit board (indicated by arrows)
Simply wipe these surfaces with alcohol and functionality will be restored.
Button modules are different. Some have contact through the printed circuit board, others have contact through the side petals to the flashlight body.
Just bend this petal to the side so that the contact is tighter.
Alternatively, you can make a solder from tin so that the surface is thicker and the contact is pressed better.
All LED lights are basically the same
The plus goes through the positive contact of the battery to the center of the LED module.
The negative goes through the body and is closed with a button.
It would be a good idea to check the tightness of the LED module inside the housing. This is also a common problem with LED lights.
Using round nose pliers or pliers, rotate the module clockwise until it stops. Be careful, it is easy to damage the LED at this point.
These actions should be quite enough to restore the functionality of the LED flashlight.
It’s worse when the flashlight works and the modes are switched, but the beam is very dim, or the flashlight doesn’t work at all and there’s a burning smell inside.
Problem 2. The flashlight works fine, but it’s dim or doesn’t work at all and there’s a burning smell inside
Most likely the driver has failed.
The driver is an electronic circuit on transistors that controls the flashlight modes and is also responsible for a constant voltage level, regardless of battery discharge.
You need to unsolder the burnt driver and solder in a new driver, or connect the LED directly to the battery. In this case, you lose all modes and are left only with the maximum one.
Sometimes (much less often) the LED fails.
You can check this very simply. Apply a voltage of 4.2 V/ to the contact pads of the LED. The main thing is not to confuse the polarity. If the LED lights up brightly, then the driver has failed, if vice versa, then you need to order a new LED.
Unscrew the module with the LED from the housing.
Modules vary, but as a rule, they are made of copper or brass and
The weakest point of such flashlights is the button. Its contacts oxidize, as a result of which the flashlight begins to shine dimly, and then may stop turning on altogether.
The first sign is that a flashlight with a normal battery shines dimly, but if you click the button several times, the brightness increases.
The easiest way to make such a lantern shine is to do the following:
1. Take a thin stranded wire and cut off one strand.
2. We wind the wires onto the spring.
3. We bend the wire so that the battery does not break it. The wire should protrude slightly
above the twisting part of the flashlight.
4. Twist tightly. We break off (tear off) the excess wire.
As a result, the wire provides good contact with the negative part of the battery and the flashlight
will shine with proper brightness. Of course, the button is no longer available for such repairs, so
Turning on and off the flashlight is done by turning the head part.
My Chinese guy worked like this for a couple of months. If you need to change the battery, the back of the flashlight
should not be touched. We turn our heads away.
RESTORING THE OPERATION OF THE BUTTON.
Today I decided to bring the button back to life. The button is located in a plastic case, which
It's just pressed into the back of the light. In principle, it can be pushed back, but I did it a little differently:
1. Use a 2 mm drill to make a couple of holes to a depth of 2-3 mm.
2. Now you can use tweezers to unscrew the housing with the button.
3. Remove the button.
4. The button is assembled without glue or latches, so it can be easily disassembled with a stationery knife.
The photo shows that the moving contact has oxidized (a round thing in the center that looks like a button).
You can clean it with an eraser or fine sandpaper and put the button back together, but I decided to additionally tin both this part and the fixed contacts.
1. Clean with fine sandpaper.
2. Apply a thin layer to the areas marked in red. We wipe off the flux with alcohol,
assembling the button.
3. To increase reliability, I soldered a spring to the bottom contact of the button.
4. Putting everything back together.
After repair, the button works perfectly. Of course, tin also oxidizes, but since tin is a fairly soft metal, I hope that the oxide film will be
easy to break down. It’s not for nothing that the central contact on light bulbs is made of tin.
IMPROVING FOCUS.
My Chinese had a very vague idea of what a “hotspot” was, so I decided to enlighten him.
Unscrew the head part.
1. There is a small hole in the board (arrow). Use an awl to twist out the filling.
At the same time, lightly press your finger on the glass from the outside. This makes it easier to unscrew.
2. Remove the reflector.
3. Take ordinary office paper and punch 6-8 holes with an office hole punch.
The diameter of the holes in the hole punch matches perfectly with the diameter of the LED.
Cut out 6-8 paper washers.
4. Place the washers on the LED and press it with the reflector.
Here you will have to experiment with the number of washers. I improved the focusing of a couple of flashlights in this way; the number of washers was in the range of 4-6. The current patient required 6 of them.
INCREASE THE BRIGHTNESS (for those who know a little about electronics).
The Chinese save on everything. A couple of extra details will increase the cost, so they don’t install it.
The main part of the diagram (marked in green) may be different. On one or two transistors or on a specialized microcircuit (I have a circuit of two parts:
inductor and a 3-leg IC similar to a transistor). But they save on the part marked in red. I added a capacitor and a pair of 1n4148 diodes in parallel (I didn't have any shots). The brightness of the LED increased by 10-15 percent.
1. This is what the LED looks like in similar Chinese ones. From the side you can see that there are thick and thin legs inside. The thin leg is a plus. You need to be guided by this sign, because the colors of the wires can be completely unpredictable.
2. This is what the board looks like with the LED soldered to it (on the back side). Green color indicates foil. The wires coming from the driver are soldered to the legs of the LED.
3. Using a sharp knife or a triangular file, cut the foil on the positive side of the LED.
We sand the entire board to remove the varnish.
4. Solder the diodes and capacitor. I took the diodes from a broken computer power supply, and soldered the tantalum capacitor from some burnt-out hard drive.
The positive wire now needs to be soldered to the pad with the diodes.
As a result, the flashlight produces (by eye) 10-12 lumens (see photo with hotspots),
judging by the Phoenix, which produces 9 lumens in minimum mode.
This was my first order on this site.
I have long wanted to buy myself a headlamp, but here is such an interesting offer, and the price is less than 100 rubles, how could I resist?!
If anyone is interested in a continuation, please see the cut! Fans of dismemberment - please take care :-)
There are many offers of variable-focus headbands on the site and offline, but, personally, I consider a variable-focus headband to be a waste of money.
In general, the niche of “magicians” is extremely limited, although sometimes they can be useful.
I have both on my farm, but more on that below.
In general, I was looking for a single-hop headband with a reflector, and I found it.
The flashlight arrived in a month, delivered in a cardboard box. 
Inside is the flashlight itself and the charger: 
Modes.
The flashlight has three operating modes; modes are switched using a button on the end of the flashlight itself. The button is tactile, i.e. with a click without fixation, for example, like on a mouse.Modes switch cyclically: strong -> medium -> strobe -> off.
The last mode is useless, it would be better if they made a weak mode.
The modes are duplicated by illuminating the white insert on the battery pack with a red LED.
Here I measured the currents:
it turned out something like this:
-Strong mode - 1600 mA.
-Medium mode - 550 mA.
Using a flashlight, we calculate the luminous flux:
-Strong mode - 600 lumens
-Medium mode - 220 lumens.
Characteristics.
Let's see what the Chinese promise us:-Diode XM-L bin T6 - not bad.
-A light flux of 1500 lumens is a lie, hops cannot produce more than a thousand; by the way, the website honestly states a light flux of 600 lumens, which is more or less true.
-Visibility is indicated at 100m, on the website it is 150 - I believe it.
- Operating time - 20 hours - a lie, maximum 14 on low mode and powerful batteries, in reality - less.
-Moisture protection is a lie, but you can finish it.
-Light - cool white 6500K.
-Powered by one or two 18650 batteries in a separate box, the kit includes charging for a normal outlet.
-The lantern has three elastic straps with adjustment (so-called thongs).
-Smooth (SMO) aluminum reflector.
-Aluminium case.
Charger.
Charging is suspiciously easy.Characteristics:
The charging socket is located on the battery block and is closed with a rubber plug.
As test subjects, I used cheap cans labeled as 4000 mAh, with a real capacity of about 1400.
It takes a very long time to charge, it turns off at 4.23 V.
Giblets and charging process
Charging: 
Charging complete: 
Head.
The head is made of aluminum alloy and has fins for cooling the flashlight; it is attached to the headband using one Phillips screw.
The hole for the cable should be sealed with silicone sealant...
Unscrew the bezel and take out the glass.
O-ring present:
The edges of the glass are not processed; between the bezel and the glass there is a green rubber seal with a light accumulator. It glows quite well, at the level of a similar rubber band of the Convoy flashlight.
The reflector is smooth, aluminum.
Reflector.
Under the reflector is a star with a diode and a guide for the reflector.
There is no hole under the diode, nor is there any thermal paste.
On the other side there is a button and wires.
There is nothing between the pill and the body. Pressing is carried out due to the thread of the bezel.
The processing of the body is lame.
The elastic band of the button is light blue, without a light accumulator.
As a modification, I applied thermal paste under the diode and in the places where the pill fits. It gets hot, which means it removes heat well.
Battery pack and brains.
The battery pack is designed to accommodate two 18650 batteries.The batteries are connected in parallel.
The circuit allows the use of one battery installed in any slot.
Protected batteries do not fit, I checked it personally.
ATTENTION!
If you insert two batteries, they must be of the same brand, capacity and both fully charged, in order to avoid bad consequences.
The battery pack is equipped with a rubber cover, which is secured with a steel ring. It closes tightly, no complaints. The cover is quite thin, so you have a good chance of feeling the heat from the discharge of the battery on the back of your head.
We disassemble the block; to do this, you need to unscrew four screws.
There is a driver on the back side.
As you can see, the charger is connected directly to the batteries.
Who is interested in microcircuit markings:
Left: 2812.
Right: 9435 / PDA00096-1S.
In the center there is a red SMD LED that duplicates the operating modes of the flashlight.
The wires going to the head are not particularly thick.
I suspect the flashlight parameters can be adjusted, but I couldn’t find a manual for the circuit.
The white insert on the outside of the block is held in place by pressing it with the battery pack; for sealing purposes, it would be a good idea to place it on the sealant.
Feel.
It sits well on the head. It reacts adequately to jumping; in order to change the angle of the head, a certain effort must be made. The controls are not very convenient; it would be better if the button was placed somewhere on the side or behind.Light and comparison with other lanterns.
As opponents I chose four different flashlights on one 18650 element, two of which with zoom.All flashlights in the test were powered by freshly charged Samsung ICR18650-30B batteries; one such battery was used in the headlamp.
In order:
- Convoy S8. XM-L2-T6-3B (neutral shade, when I ordered it I thought it would be colder), 2.8 A, approximately 1000 lumens, “crumpled” OP reflector. Used as a bag EDC.
- UltraFire WF-502B. MC-E bin K (neutral shade), approximately 700 lumens, “creased” OP reflector. The diode consists of four crystals. One of my first normal flashlights, bought many years ago.
- A Chinese lantern with a zoom taken, for example, from a friend. Cold diode XM-L T6, 1.6 A, approximately 600 lumens. This flashlight will allow you to compare flashlights of different optical designs, on the same diode with the same brightness.
- Another Chinese with a zoom, Diode - neutral CREE XR-E bin R2, 1 A, about 260 lumens, purchased a long time ago, used as a working flashlight for electrical work and illumination of various large containers. The flashlight is also used for photographing small objects as additional illumination, and in this it is very good due to its even filling with neutral light.
The purpose of this modification is to obtain a flashlight with a wide soft light for use at short distances.
Everything is extremely simple, unscrew the bezel, take out the glass, carefully trace the glass on the laminator film, cut it out and paste it in front of the glass with the smooth side facing the glass, the frosted side facing out.
It all holds very tightly, since the bezel reliably fixes the film. It is also very easy to remove.
Distance from the flashlight bezel to the wall: 1 meter exactly.
The distance to the lens is approximately 2.5 meters.
The wall has a slightly bluish tint.
Camera parameters:
Canon 600D + EF-S 18-55mm IS II, wide angle, open aperture, full manual mode with the following parameters: 
Headband: 
In reality, the color is more bluish than purple. A bright, but rather narrow hot spot, very wide and uniform side illumination. There would also be an OP reflector here...
Modified forehead: 
Convoy: 
Wide, blurry hotspot with a developed corona, medium-width side flare.
Ultrafire: 
Due to the fact that the diode has four crystals, an artifact in the form of a dark spot is observed in the center, visible on the right beamshot.
Zoom on XM-L T6: 
The shade is more purple. the beam is not particularly wide. Illumination is uniform.
Zoom on XR-E: 
The closest light to white. The size of the beam is not very different from the previous one.
One on one. Be careful, there is a lot of traffic.
Maximum: 
On medium: 
At minimum: 
Conclusions.
In general, I'm happy with the purchase. This flashlight requires some work, but it is not complicated and is accessible to any user. All that is required is to spread thermal paste in the right places and seal a couple of elements with sealant.In terms of light: the light is not bad, bright, wide, but I don’t like a hotspot that is too bright and narrow.
As an improvement, I’ll try to find and order a “crumpled” reflector. As a temporary measure, I’ll try to cut a diffuser out of film for the laminator, which will allow me to achieve a certain versatility: if I need a low-level flood light, I’ll attach the film, if I need range, I’ll remove it.
I recommend purchasing this flashlight. For this money- you can’t find a better forehead protector.
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 is the printed circuit board charger and indications. 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, usually one LED 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. So in a simple way the possibility of supplying voltage from the charger to the LEDs EL1-EL10 while charging the battery will be excluded.
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, 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, a second one was repaired, with the same fault. On the body of the flashlight there is information about the manufacturer and technical specifications I couldn’t find it, 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, while 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 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 produced an unstabilized constant pressure 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 was an ordinary power supply used as a charger?
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 failures of repaired Chinese LED lamps showed that they all failed due to poorly designed electrical diagrams. 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 was repaired Chinese manufacturer trademark RED. 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. Appearance 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.
Lead-acid AGM batteries of different types were installed in the Chinese lanterns being repaired. overall dimensions without marking, voltage 3.6 V. According to calculations, the capacity of these batteries ranges from 1.2 to 2 A×hours.
You can find a similar acid battery on sale Russian manufacturer for a 4V 1Ah Delta DT 401 UPS, which has an output voltage of 4 V with a capacity of 1 A×hour, costing a couple of dollars. To replace it, simply re-solder the two wires, observing the polarity.
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