In this article you will learn how to inexpensively convert a screwdriver battery from Ni Cd to Li Ion 18650 batteries, thereby modernizing screwdriver battery, making it more powerful and increasing the time battery life. All stages of the conversion are described in detail, so there should be no problems, all the necessary components are indicated and available.

Required components for conversion

For rewhitening, high-current 18650 batteries capacity 2500 mAh. Data batteries They have already welded leads for soldering, which is very convenient and, in addition, you can significantly save on battery compartments. You can order them online and are supplied in batches of 4 or 6 pieces. You can buy them using the links below:

Buy 18650 batteries - 6 pcs.

Buy 18650 batteries - 4 pcs.

Also for the conversion you will need two BMS 12.6V 40A boards, bought here:

Buy BMS board 12.6V 40A

The charger will also need to be redone and for this you will need a voltage and current stabilization module.

Video on how to remake Charger see the end of the article

Buy voltage and current stabilization

At the time of the conversion, all components (for two batteries) cost only 1,100 rubles, this is much cheaper than buying a new battery for a screwdriver, which will contain the same Ni Cd batteries. After looking at prices on the Internet, I discovered that one battery costs from 1200 rubles, and to remake TWO batteries, I spent only 1100! All links to components can also be found at the end of the article!

Battery conversion

The first step is to carefully disassemble the battery case and throw away the old Ni Cd batteries.

Then you need to disconnect the battery power terminal.

You need to solder two wires to it, preferably with a large cross-section; in this modification, wires with a cross-section of 4 mm² and a length of approximately 100 mm were used. In the photo above you can see the red wire, it was left in order not to confuse the polarity; it is advisable to also solder the red wire to this wire in order to avoid troubles and you will know for sure that it is +.

You need to solder the negative wire to the shiny contact:

Then you need to insert the terminal with the soldered wires back into the housing in its place, being sure to observe the polarity!

To fix the terminal, you can pour hot glue inside the glass; I haven’t found a better fixing option, especially since it holds very well!

Now you can start soldering the batteries. We remove the heat-shrink tube from the batteries and bend them so that they can be soldered in series.

Next, we apply hot melt glue to the side of the resulting battery, where the contacts stick out to the top, and glue the BMS board as shown in the photo below. Please note that the plus and minus of the board and battery are opposite each other!!!

Then we bend the battery contacts onto the board contacts and solder them, starting from the negative!

We solder a short wire to the contact of the B1 board, the other end of which we solder to the junction of the batteries!

We also solder a short wire to contact B2, the other end of which is soldered to the junction of the batteries on the opposite side!

Well, at the end, we solder the last, positive contact.

Now it remains to connect the terminals of the case with the resulting battery; to do this, solder the red wire to the “P+” contact, and the blue, negative wire to the “P-” contact.

This completes the battery conversion! All that remains is to secure the manufactured battery and put the second part of the case in place. Not much was spent on converting two batteries. more than an hour time and, as mentioned above, 1100 rubles of money. After the tests, the screwdriver began to work no worse than with the factory battery and, I would say, much better in terms of power and the charge lasts longer. I advise everyone to remake their old batteries!))
Buy charger socket
Buy a soldering iron

For those who have no desire to remake the charger, you can buy a ready-made one using the link below.

Buy a ready-made charger

The idea of ​​how to convert a headlamp into a battery-powered one arose a long time ago, this is especially true for fishing and when. Since it is not profitable to constantly buy batteries in our age of mobile phones. So, after thinking about it and ordering the necessary spare parts, which I will describe below, I began to modify the headlamp for batteries with my own hands, using a Chinese circuit with charging. This makes it possible to charge the battery both in the car and from a regular micro USB of a modern phone. I usually order from Aliexpress, although it is possible to find it in stores, but it’s 2 times more expensive.

A very bright and functional headlamp, for such a price, but for some reason I haven’t found one on sale now
I tried to remake this model as well, but it was a little inconvenient to install the button and the diode plate got hot, so I had to isolate it from the battery with a piece of plastic. But in the end the flashlight works properly

The flashlight was delivered to the post office in 20 days, which made me happy :) .

The idea is very simple and anyone can do it; all you need is a small battery from an old cell phone, it contains a Li-Ion battery with protection. The voltage parameters are ideal, the LED flashlight has a voltage range from 4.5 - 2V, and the 3.7V battery in a charged state of 4.2V has a decent capacity, which can be increased by adding another battery in parallel. You just need to correctly identify the contacts (most have plus and minus indicated), all that remains is to carefully solder the contacts so as not to melt and avoid a short circuit.
The problem with charging via a regular micro USB can be easily solved by ordering a small board costing about 20 rubles. Micro USB plays a very important role in controlling the charging and turning off the ice lamp when the battery is low.

The board has LED indicators that indicate in color when the converted LED flashlight is charging. Thus, the modification of the Chinese headlamp comes down to soldering the wires to the terminals.
Using this board, converting any flashlight to lithium is quite simple, it is only important to know how many volts the battery produces.

Charging board, purchased in an online store with free delivery

Perhaps I ordered 10 pieces for myself at once because it is universal and can be used in children's toys.

Battery connection diagram

Board parameters

• Input voltage from Micro USB: 5V
• Charging cut-off voltage: 4.2V ± 1%
• Maximum charging current: 1000mA
• Battery over-discharge overvoltage protection: 2.5V
• Installed overcurrent protection current: 3A
• Board size: 2.6*1.7CM

In fact, this is a separate board that is used in a power bank, and if you buy an additional USB output, you can charge your phone

Let's start remaking

Exploded view of the lantern and the first stage of assembly

Now, about the conversion of the flashlight itself to use a battery instead of batteries, most flashlights use 3 AA 1.5 V in size, comparable to a mobile battery, and fits quite well in the main body, you just have to expand the seat. After simple manipulations, having unscrewed or cut out all the excess, we mount all the parts in place using hot-melt adhesive.

LED flashlight conversion diagram
Solder all the parts in place using a heat gun
If necessary, you can increase the capacity by connecting 2 batteries
We get a modernized headlamp with a mini USB input

In conclusion: the LED flashlight worked actively for 3 nights on old telephone batteries without recharging. Perhaps it would have been enough for more, I didn’t test it before the cutoff. Lithium batteries do not like to be completely discharged. Overall, very pleased at the cost of 140 rubles. The only thing is that it is very bright, which is not always necessary. I was pleased with the presence of charge indicators on the board. When charging via USB, it glows red when the battery is charged blue.

Almost any flashlight can be converted in this way, the only question is the size of the battery. For example, iPhone batteries are not very practical, and if you tear off the contacts from the connection board carelessly, they will not be soldered.

Do not use lithium batteries if they are swollen - it is unsafe!

It happens that the protection on the board is triggered, and you need to revive it, in this case, apply voltage from the power supply or power bank. If the phone batteries are very old, then the protection of the headlamp will naturally work faster and it will go out. Although batteries from an old Nokia (more than 4 years old) work properly.

Save money when purchasing and, accordingly, buy cheaper (this is when % from the purchase accumulates). So you just install a browser extension and the money gradually accumulates on its own.

Useful video collection on modifying flashlights

Selecting and purchasing a flashlight is a difficult and tedious task. At least for me. I approach this matter with all meticulousness and responsibility. It is necessary to take into account all the advantages and disadvantages of the product. Type and capacity of batteries, parameters, weight, degree of waterproofness and much more. So that he does not fail at the most inopportune moment. I wanted to buy a small pocket flashlight, waterproof, powered by a single 18650 battery. However, I could not find the desired product in local stores. I was already thinking about ordering from an online store and, after waiting 2-4 weeks, getting what I needed... But suddenly I came across something that almost suited me. Almost. The flashlight had the dimensions I needed and all the necessary qualities, but there was one “but” - it worked on three AAA batteries (pinky).

Having a special container with four constantly charged 18650 batteries in my backpack, I absolutely do not want to use other batteries. Moreover, such small and not capacious ones as little ones. But there is always a way out! Having examined this flashlight in the store, a modification scheme immediately emerged, and without thinking twice, I purchased it with the goal of remaking it in my own way in the near future.

Will need

• A burr machine with a cutting disc (or an emery machine).
• Soldering iron, tin and flux.
• Plastic tube (for housing insert).
• Aluminum self-adhesive foil.
• Scissors.
• Stationery knife.
• File.
• Sandpaper (or sanding cloth).
• Secondary glue.

Flashlight conversion

The main problem is that the flashlight’s “native” power supply (the housing in which three AAA batteries are located) is slightly wider, and one and a half centimeters lower than the 18650 battery.

This means that the body of the flashlight itself will be too small in height for 18650. In terms of voltage, 18650 is almost identical to three little finger batteries, 18650 produces 3.7 volts, and three little finger batteries give a total of 3.6 volts (1.2 × 3 = 3.6) . This means that if the body is too small, you need to lengthen it. It was quite problematic to find a suitable insert tube that would fill the extra space between the battery and the walls of the flashlight. In the end, I was never able to get a suitable insert... I simply took a more or less suitable tube that included 18650 and, installing it on a drill, removed the excess thickness from the rotating workpiece from the outside with coarse sandpaper! So, let's disassemble the flashlight. Unscrew the front and back parts of the flashlight from the middle one and set it aside. Using a burr with a cutting disc, we cut the middle part of the flashlight body into two equal halves.

We sand the sawn edges with sandpaper so that they become even and smooth.

Next, we insert the liner tube into the front part of the flashlight with a reflector screwed onto it, and put the back part on top with the bottom and button screwed onto it. The result is a new, elongated body that fits the width of 18650.

Now let’s adjust the height, insert the battery into the case, measure out the excess on top, take out the liner and cut off the measured edge with a utility knife.

Also in the design of the flashlight, inside the body, there are two metal rings and a metal strip that connect the plus and minus on the switch button. Naturally, after lengthening the body, the metal strip became too short for the new design. We also had to adjust the rings to fit the liner tube.

The layer of soft plastic was quite easily and quickly removed with a file from the edges of the liner, where the ring should sit.

The second, the front ring, was inserted inside the front of the flashlight, where the reflector, lens and LED are located, so there was no need to mess with it. Let's do it simpler with the metal strip connecting the rings; Simply stick a strip of self-adhesive aluminum foil onto the liner.

We put the back ring on the prepared back part of the liner.

Now let's work on the “head” of the flashlight. On the former power supply, with pinky batteries, there was a small bulge on the positive contact that was in contact with the positive. On the 18650 battery, both contacts are flat, so I had to solder the same spring to the positive contact of the front part of the flashlight as is on the negative, rear part.

Now let's put the new body together.

All the details fell into place like family! All that remains is to drip super glue into the joints between the liner and the sawn edges of the body to restore the tightness. There is still space left, or rather, it turned out to be a groove that was formed after installing the sawn ends of the old case on the liner. This is an individual matter for everyone; Before gluing all the parts, you can fit a piece of tube with suitable parameters to this place. I decided to just wrap a little tape and black insulating tape there; Might be needed somewhere.

So we "translated" this device from three batteries to one equal in voltage, thereby saving yourself from the tedious charging of the power supply with small and low-capacity batteries.

The above changes did not in any way affect the quality of the flashlight (brightness and water resistance). Except that it has become one and a half centimeters longer.

Headlamp with 18650 battery In the previous article we looked at a very good modern chip - a lithium battery charge controller, now it's time to apply this circuit to
Headlamp with 18650 battery

Headlamp with 18650 battery

In the previous article we looked at a very good modern chip - a lithium battery charge controller, now it's time to put this circuit into action by upgrading several flashlights. Next, see a couple of applications of memory boards with TP4056 in flashlights:

Batteries taken from old ones cell phones, found with identical capacities, balanced and soldered into a block. In the first option, 1.5 A, in the second, 1 A. They charge quickly - approximately 1-3 hours, depending on the current used.

Next, I started converting another old camping flashlight for a 18650 lithium battery, I drew a signet for it, it came out almost like the original, but smaller. I tried charging, it works. I'll collect the whole lantern.

But I finished another old camping lantern. It is possible to change lenses for different focusing of the light flux. I replaced the acid battery with a 18650 type battery and added a charger on the same TP4056, the capacity of the used battery is 1.3 A:

Another case. They gave me a good case from an ancient incandescent flashlight, rechargeable from the mains.

The gel battery built into it was hopelessly dead for a long time. After some thought, it was decided to build into it a block of parallel lithium batteries, 4 pieces of 800 mA each, and expand the functionality by integrating two LEDs into the housing for 60 mA and 150 mA.

In place of the removed retractable plug, an additional aluminum plate-radiator was cut out and an SMD LED with an operating current of 150 mA was screwed on. And in place of the former light bulb, an 8 mm round LED rated at 60 mA was installed.

There was a lot of free space left inside, so a ready-made memory was built into the flashlight, again for TR4056. The LEDs on the charger board fit perfectly into the hole of the former power LED. For these charge indication LEDs, a conical indicator was machined from plexiglass and glued into the case. The result is a compact and resource-intensive (3.2 A) pocket flashlight with recharging from 5 V.

Protective plexiglass was also added to the body to protect the LED from dust. And this is a disassembled body, for a clearer visual acquaintance with the contents of the converted flashlight. There is still empty space left; it is quite possible to add a boost converter for recharging a cell phone.

In this way, old electronic structures and devices can be given the opportunity to continue to serve, using a modern electronic base in a new technical quality. And all this can be done with a small, cheap 4056 microcircuit. I was with you Igoran.

Headlamp with 18650 battery

Literally, the flashlight was disassembled on the knee, the network connector was removed (the charge was from 220 in the original) and the “interfering wires” - You really shouldn't have touched them :)
Instead of the original battery, I used a power bank with a 2600 can, removed the original case from the power bank (there is no use for metal next to the printed circuit board), and secured it with electrical tape so that the structure would not fall apart due to vibrations or possible falls of the phone.


In fact, everything can be done MUCH more accurately, but I was interested in the simplicity and speed of the solution at the time of remodeling.




This is approximately how it turned out (the wiring could not have been pulled out through the power bank, but at first there was an idea for a slightly different arrangement, I did not redo it).
The power bank itself was secured by inserting it into the former network connector, even without additional ones. the mount sits quite firmly




Main advantages:
The lantern is alive!
Quite easy and inexpensive!
It is easy to change the battery (in case of failure) - they are common and inexpensive.
You can charge from any USB (including in a car), and also, if necessary, use the flashlight itself as a power bank. There is a flashlight charge control.

The flashlight shines normally. I didn’t try to time it, but it shines for a VERY long time, several hours for sure, I didn’t try to discharge it at once.