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How to make a charger for 18650 batteries. How to build a charger for lithium-ion batteries at home

In this article, I will show you how to make a simple Charger for these batteries.

Assembly and testing of the charger.

We will need:

1. Syringe 20ml
2. 2 copper wires
3. Spring from the battery holder (from old technology or toys)
4. Charge module lithium batteries 18650 on TP4056 5V 1A with micro USB interface ()
5. Hot glue
6. Battery type 18650 ()

From tools:

1. Soldering iron
2. Glue gun
3. Stationery knife

Charger manufacturing

We will need a 20 ml medical syringe and an 18650 battery.

The syringe is ideally suited for the size of the battery.

We cut off the nozzle of the syringe with a clerical knife (where the needle is inserted) so that it does not interfere with us in further operation.

We take a spring from battery holders from old technology (for example, from a remote control or toys).
We pass the copper wiring from below into the hole and fix it on the spring spiral as shown in the photo.

We take the 18650 lithium battery charge module on TP4056 5V 1A with micro USB interface and attach it with hot glue to the syringe in a convenient place. Observing the polarity, we bring the wires to the module and solder them with a soldering iron.

A little about the TP4056 5V 1A module.

Designed to charge lithium batteries 3.7V current up to 1A. This module, due to its size and micro USB connector, can be easily integrated into various devices and can serve as an alternative replacement for failed lithium battery chargers. Supports different types lithium batteries, including the popular 18650. The module is not protected against reverse polarity (non-polarity) connection, so be careful when connecting batteries.

We cut off a small piece from the syringe piston at the base with an elastic band, as shown in the photo. This will fix the battery inside the syringe.

We make a hole in the syringe for copper wiring so that it can touch the positive contact of the battery. The hole must be made at a level when the battery is not fixed by the plunger of the syringe. The photo shows that I mistakenly made one lower hole in the fixed position of the battery.

After passing the wire into the hole made and fixing the battery with a piston, you can start the test of the charger.

The charger is stable. The battery does not heat up while charging. Thanks to the indication on the module, you can monitor the charging process (red LED) and the completion of the battery charging process (blue LED).

The device is relevant due to its low cost consumable for a homemade charger and not complicated execution.

It can also be made from 20 ml syringes and holders for of this type batteries and use them in various crafts.

Of the huge variety of li-ion batteries, the 18650 battery is especially in demand. Long service life and stable battery parameters are ensured by observing a number of rules, but the main condition affecting the performance of lithium- ion batteries 18650, is their correct charging.

Rechargeable 18650 battery

The main positive characteristics of 18650 lithium batteries are the ability to accumulate a large amount of charge, it is enough to store this charge long time, lack of memory properties and scanty specific gravity.

The memory effect is primarily characteristic of nickel-cadmium batteries. This effect means some loss of battery capacity if it is charged until it is completely discharged.

For 18650 battery and othersli-ion batteries has its own marking:

The first two digits indicate the diameter in millimeters;
The next two digits indicate the length in millimeters;
The last digit indicates the type of battery execution (0 - indicates a cylinder).

On the initial stage production and use, such batteries were explosive due to uncontrolled chemical reactions inside and short circuits inside the batteries. To prevent such breakdowns, all batteries in general and 18650 in particular are equipped with special boards with controllers that prevent damage to the battery due to critical overheating and depressurization.

Optimal storage conditions for lithium-ion batteries are achieved at 5°C with a 40% battery discharge.

How to charge a 18650 battery

Well-known memory manufacturers use a two-stage battery charging method in them.

The two-stage charging method includes:

The task of the charger at the first stage is reduced to charging with a stabilized current. The current strength during charging is determined by the nominal capacity of the battery with a coefficient of the order of 0.2 to 0.5. During the charging process, the voltage is automatically increased to maintain a stable current. At a voltage value of 4.2V, the charging process stops at this stage. By this time, the battery has time to replenish its capacity by 70-80%. In order to shorten the charge time for lithium batteries, an accelerated charge process is used. In this case, the charging current is taken with a coefficient of 0.5-1.0;
Charging 18650 in the second stage takes place with a constant voltage. The 18650 charging board supports Ucharge ~ 4.15-4.25V and controls the amount of current. The value of the current during charging gradually decreases to a value of 0.05-0.01 of the battery capacity. Accordingly, the charging process is considered complete.

In addition to the above charge stages, for 18650 li -ion batteries, a preparatory charge of the battery is applicable. Charging is carried out with a reduced current until the voltage on the battery reaches 2.8V.

Despite the indispensability of the two-stage charging system, there are some drawbacks. Since the battery voltage is measured during the passage of a large charging current through it, then, depending on internal resistance battery, measurements may vary. In this regard, the voltage can reach a value of 4.3-4.4V, which has an extremely negative effect on the battery. In practice, it is better to resort to using chargers with current pulses if there are gaps between them. During these intervals, the voltage on the battery is measured. The closer the voltage is to the value of a fully charged battery, the shorter the pulse gives the charger. Accordingly, when the measured voltage reaches 4.15V, the supply of pulses will stop.

Charger circuits

Radio amateurs quite often wonder how to charge lithium-ion batteries and how to charge them with maximum savings in resources, effort and time. The presence of the necessary element base and elementary knowledge will not leave a radio amateur without a charger.

The assembled do-it-yourself 18650 charging, shown in the picture below, is adjusted by setting the output voltage to 4.2V with a tuning resistor R8 and the charging current with resistors R4, R6. The charging process is considered completed after the HL1 LED goes out.

Important! For normal functioning LM317 chips for 18650 batteries must have input voltage within 8-12V.

A home-made charger for 18650, which incorporates integrated circuits MAX (1551 or 1555), qualitatively differs from competitors in a number of properties and features:

The ability to charge the battery from USB or from a separate power supply;
No external transistors and diodes;
Protection against excessive overheating by artificially lowering the charging current.

It will not be difficult to get a pulse memory for 18650, assembled with your own hands, due to the lack of a microcircuit in the device. The presented charger for 18650 fulfills all the requirements and functions of pulse charging. An additional advantage of the charger is the ability to replace element base domestic counterparts. Smart charging for 18650 batteries, assembled and tested with your own hands, will last no worse than the purchased charger.

The stated topic revealed such questions: how to charge a battery, how to charge a li-ion battery. When using a charger for 18650 batteries, purchased or homemade, the main thing is to check the output values \u200b\u200bwell. Next, you can pay attention to additional options in the form of LCD displays, the number of channels, the presence of backlight, car adapter.

Video

Batteries play an important role in any off-line machine. Rechargeable batteries are quite expensive due to the fact that you need to purchase a charger with them. Batteries use different combinations of conductive materials and electrolytes - lead-acid, nickel-cadmium (NiCd), nickel-metal hydride (NiMH), lithium-ion (Li-ion), lithium-ion polymer (Li-Po).

I use lithium-ion batteries in my projects, so I decided to make my own charger for lithium 18650 batteries, and not buy expensive ones, so let's get started.

Step 1: Video

The video shows the assembly of the charger.
link to youtube

Step 2: List of electrical components

Show 3 more images

List of components needed to assemble the charger for rechargeable batteries 18650:

Charger module based on TP4056 chip with battery protection
Voltage stabilizer 7805, you will need 1 piece
Capacitor 100 nF, 4 pcs (not needed if there is a 5V power supply)

Step 3: List of Tools

To work, you will need the following tools:

hot knife
Plastic box 8x7x3 cm (or close in size)

Now that everything the right tools and the components are ready for work, let's deal with the TP4056 module.

Step 4: Li-io battery charger module based on TP4056 chip

A little more about this module. There are two versions of these modules on the market: with and without battery protection.

The breakout board containing the protection circuit monitors the voltage with the power supply filter DW01A (Battery Protection Integrated Circuit) and FS8205A (N-Channel Transistor Module). Thus, the breakout board contains three integrated circuits (TP4056+DW01A+FS8205A), while the charger module without battery protection contains only one integrated circuit (TP4056).

TP4056 - single cell Li-io battery charger module with linear charge direct current and tension. The SOP package and few external components make this module an excellent choice for DIY electrical applications. It charges over USB just as well as through a regular power bank. The pinout of the TP4056 module is attached (Figure 2), as is the Charging Cycle Chart (Figure 3) with constant current and constant voltage curves. Two diodes on the breakout board indicate the current charge status - charging, charging termination, etc. (Fig. 4).

In order not to damage the battery, charge 3.7 V lithium-ion batteries at a constant current value of 0.2-0.7 of their capacity until output voltage does not reach 4.2 V, after which the charge will be carried out with a constant voltage and a gradually decreasing (up to 10% of the initial value) current. We cannot interrupt the charge at 4.2V, as the charge level will be 40-80% of the full capacity of the battery. The TP4056 module is responsible for this process. One more important point– The resistor connected to the PROG pin determines the charging current. In modules on the market, a 1.2KΩ resistor is usually connected to this pin, which corresponds to a charging current of 1A (Fig. 5). To get other values \u200b\u200bof the charging current, you can try to put other resistors.

DW01A is a battery protection integrated circuit, Figure 6 shows a typical wiring diagram. MOSFETs M1 and M2 are connected externally by an FS8205A integrated circuit.

These components are installed on the TP4056 Lithium-Ion Battery Charger Breakout Board, referenced in Step 2. We only need to do two things: apply a voltage in the range of 4-8V to the input connector, and connect the battery terminals with the + and - terminals. module TP4056.

After that, we will continue to assemble the charger.

Step 5: Wiring Diagram

To complete the assembly of electrical components, we solder them in accordance with the diagram. I've attached a diagram in Fritzing and a photo of the physical connection.

+ we connect the contact of the power connector to one of the contacts of the switch, and - the contact of the power connector is connected to the GND pin of the stabilizer 7805
The second contact of the switch is connected to the Vin pin of the stabilizer 7805
Install three 100nF capacitors in parallel between the Vin and GND pins of the voltage regulator (use a breadboard for this)
Install a 100nF capacitor between the Vout and GND pins of the voltage regulator (on the breadboard)
Connect the Vout pin of the voltage regulator to the IN+ pin of the TP4056 module
Connect the GND pin of the voltage regulator to the IN pin of the TP4056 module
Connect the + terminal of the battery compartment to the B+ pin of the TP4056 module, and the - terminal of the battery compartment to the B-pin of the TP4056 module.

This completes the connections. If you are using a 5V power supply, skip all steps with connections to the 7805 voltage regulator, and connect the + and - of the power supply directly to the IN+ and IN- pins of the TP4056 module, respectively.
If you use a 12V power supply, the 7805 will heat up when passing 1A current, this can be fixed with a heat sink.

Step 6: Assembly Part 1: Cut Holes in the Case

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In order to properly fit all the electrical components in the case, you need to cut holes in it:

Use a knife blade to mark the boundaries of the battery compartment on the case (Fig. 1).
Use a hot knife to cut a hole along the marks made (fig. 2 and 3).
After cutting the hole, the case should look like in Fig.4.
Mark the place where the USB connector of the TP4056 module will be located (Fig. 5 and 6).
Use a hot knife to cut a hole in the case for the USB connector (Fig. 7).
Mark the places on the case where the diodes of the TP4056 module will be located (Fig. 8 and 9).
Use a hot knife to cut holes for the diodes (Fig. 10).
In the same way, make holes for the power connector and switch (Fig. 11 and 12)

Step 7: Assembly Part 2: Install Electrical Components

Follow the instructions to install the components in the chassis:

Install the battery drawer so that the mounting points are outside the drawer/chassis. Glue the compartment with a glue gun (Fig. 1).
Reinstall the TP4056 module so that the USB connector and diodes fall into the corresponding holes, fix with hot glue (Fig. 2).
Replace voltage regulator 7805, secure with hot glue (Fig. 3).
Install the power connector and switch in their places, fix them with hot glue (Fig. 4).
The location of the components should look the same as in Fig.5.
Secure the bottom cover in place with screws (fig.6).
Later, I covered the rough edges left by the hot knife with black duct tape. They can also be smoothed out with sandpaper.

The completed charger is shown in Figure 7. now it must be tested.

Step 8: Test

Place the discharged battery in the charger. Turn on the power to the 12V socket or USB. The red diode should blink, which means that the charging process is in progress.

When the charge is complete, the blue diode should light up.
I am attaching a photo of the charger in the process of charging and a photo with a charged battery.
This completes the work.

Today, one of the most popular battery formats for various electronic devices is 18650. It requires proper handling during operation. The durability and functionality of this power source depends on this.

How to charge an 18650 battery should be considered in detail. This will help to understand the advice of experts.

general characteristics

Today, many sizes are used and one of the most popular is the 18650 type battery. It has a cylindrical shape. Outwardly, such a battery resembles finger batteries. Only the presented view is slightly larger in size than the usual devices.

During operation, the question necessarily arises of how to charge the 18650 battery. This is a simple procedure. However, it must be taken with all responsibility. The durability of the battery depends on the correct charging.

Batteries of the presented type are used today to power laptops, as well as electronic cigarettes. This made the presented size popular. Also, similar batteries are installed in flashlights and laser pointers. Most often, the presented devices produce a lithium-ion type. This type of battery has proven its efficiency and ease of use.

Peculiarities

Considering how to charge an 18650 battery for a flashlight, an electronic cigarette and other devices, it is necessary to describe the principle of its operation. The presented size is available in the category of lithium-ion batteries. It has small dimensions. The height is only 65mm and the diameter is 18mm.

Inside the device there are metal electrodes between which lithium ions circulate. This allows you to develop electricity to power equipment. When the charge is low or high, more ions are produced at one of the electrodes. They grow on the material, changing its volume and characteristics.

In order for the battery to work for a long time and fully, it is necessary to prevent the appearance of a deep or too high charge. IN otherwise the device will quickly fail. Depending on the rating of the battery, special types of chargers are used.

Battery Protection

Today, the presented types of batteries are available complete with a special controller or contain manganese. Previously, batteries without protection were produced. How to charge the 18650 battery correctly in this case, you had to know for your own safety.

The fact is that the device, in which there was no special protection, could overheat greatly if it was charged incorrectly or for too long. In this case, there could be short circuit and even fire or Today, the use of such structures has sunk into oblivion.

All lithium-ion batteries are designed to protect against such negative phenomena. Most often, a special controller is used. It monitors the battery capacity level. If necessary, it simply disconnects the battery. In some types of structures, manganese is included. It significantly affects the chemical reactions inside. Therefore, such batteries do not need a controller.

Charging Features

Many buyers are interested in how to charge the 18650 Li-Ion (3.7V) battery. It is necessary to familiarize yourself with the features of such a process. It is quite simple. Modern manufacturers make special devices that control battery charging.

Lithium-ion batteries have virtually no memory effect. This provides a set of rules for charging and operating batteries. The memory effect is the gradual decrease in battery capacity when the battery is not fully discharged. This property was characteristic of nickel-cadmium type batteries. They had to be completely destroyed.

On the contrary, they do not tolerate deep discharge. They need to be charged up to 80% and discharged up to 14-20%. In such conditions, the device will serve as long and productively as possible. The presence of special boards in the design allows you to simplify this process. When the capacity level drops to a critical value (most often up to 2.4 V), the device disconnects the battery from the consumer.

Charging

Many buyers of various electrical equipment are interested in how to charge a 18650 Li-Ion (3.7V, 6800mah) battery. This process is carried out using a special device. It starts charging at a voltage of 0.05 V, and ends at a maximum level of 4.2 V. Above this value, the battery of the presented type cannot be charged.

You can charge 18650 batteries with a current of 0.5-1A. The larger it is, the faster the process goes. However, a smoother current is preferable. It is better not to speed up the charging process unless the battery needs to be used urgently.

The procedure takes no more than 3 hours. The device will then turn off the battery. This prevents it from overheating and failing. On sale are devices for charging that cannot control the course of this process. In this case, the user must himself monitor its implementation. Experts recommend purchasing devices that themselves control the process. This is the safe method.

Parameters

Batteries are available in different capacities. This affects the duration of operation and the charging process. Batteries 1100-2600 mAh have a low capacity. The most popular in this category are UltraFire products. This manufacturer produces high-quality flashlights. Therefore, consumers have a reasonable question about how to charge the 18650 UltraFire battery.

In this case, it should be noted that devices with a capacity of up to 2600 mAh must be charged with a current of 1.3-2.6 A. This process is carried out in several stages. At the beginning of charging, the battery receives a current that is 0.2-1 of the battery capacity. At this point, the voltage is maintained at about 4.1 V. This stage lasts about an hour.

During the second stage, the voltage is held at a constant level. For some manufacturers of chargers, this procedure can be carried out using alternating current. It should also be noted that if there is a graphite electrode in the battery design, it cannot be charged with a current greater than 4.1 V.

Varieties of chargers

Exists simple technique how to charge the battery To do this, you will need to buy a certain type of device. On sale is a large selection of charging equipment for batteries of this type. The simplest and most inexpensive is the device for a single battery. The current level in it can reach 1 A.

Devices in which several batteries can be placed at once are very popular. Most often, such structures are equipped with an indicator. Some models can also be used for other types of lithium-ion batteries. Their landing nests have an appropriate design. Such devices are distinguished by acceptable cost and high functionality.

Also on sale are universal chargers. They can charge batteries not only of the lithium-ion type, but also of other varieties. Such units must be properly configured before the procedure.

Homemade device

Some users have a question about how to charge an 18650 battery in an emergency when a special device is not at hand. In this case, you can do it yourself. An old phone charger (for example, Nokia) will do.

It is necessary to remove the wire sheath and disconnect the minus (black) and plus (red) wires. Using plasticine, you can attach bare contacts to the battery. The correct polarity must be observed. Next, the device is connected to the network.

This charge can take up to an hour. This will be enough for the battery to ensure the correct operation of the equipment.

Experts recommend taking the charging process responsibly and its durability depends on it. Discharging the battery completely and charging it to 100% is not worth it. It is better to limit the charging process to 90%. However, periodically (every three months) you can fully discharge and fully charge the battery. This is necessary to perform controller calibration.

You can store the battery for a long time. To do this, you need to charge it by 50%. In this state, it can be about a month. At the same time, the room should not be too hot or too cold. Ideal conditions are considered to keep the temperature at 15 ºС.

By looking at how to charge an 18650 battery, you can properly maintain and operate the battery. In this case, the period of its use will be much longer.

Li-ion 18650 batteries are very widely used in many electronic devices that we use today. For example, LED lights, batteries in laptops, electric bikes or Power Bank.

These batteries are a reliable source of power, so it's also very handy to use them on DIY projects. 18650 Li-ion batteries are shaped like AA batteries, but have a 3.7V output with a capacity of 1600 to 3600mAh (AA or AAA batteries have a voltage of 1.5V/1.2V).

However, on this moment charging these batteries is still not a simple matter, as commercial chargers are quite expensive. In addition, lithium-ion batteries require a charger. good quality, otherwise the battery life will deteriorate. A balanced charger works well, but it's available in a higher price range.

So, in this tutorial we decided to make a charger Li-Ion device, which can simultaneously charge four 18650s. This charger is very easy to make and does the job of a balanced charger by cutting off power to individual batteries after a full charge.

We will need a few "spare parts" for our charger:

general purpose printed circuit board
module TP4056
paperclips
connector
PCB switches
3.7V Li-Ion batteries
soldering iron

You can buy all this in different stores, especially in foreign ones, for example, Amazon or E-bay.

Step 2: Start collecting

Take printed circuit board general purpose and place the batteries on top of the board;
Mark the distance between the edges of the batteries and their width on the PCB;
Unfold 8 paper clips and using pliers cut the clips from the edges as seen in the image above;
A total of 8 U-clamps must be made (depending on the number of batteries being charged);
Insert the U-clamps into the PCB so that the batteries can be installed between the clamps;
The clips will act as battery holders;
Also, use the leftover staples to make side stops;
Fasten the clips on the board well as shown in the figure.

Note: Make sure the clamps are not connected to each other while soldering.

Step 3: Adding Components

Place the TP4056 charging module on the PCB as shown in the picture above;
Using a marker, mark the module holes on the board;
Solder a pin in each of the marked holes;
Insert the module over the pins and carefully solder;
Use the number of modules equal to the number of batteries being charged, i.e. one module per battery;
Solder all modules to the board as shown;
Take the switches and solder them between each module on the PCB.

Note: Be sure to watch the video (below) and check out the images to avoid mistakes.

Step 4: Connecting the Components

See connection diagram above and solder all components together;
Be sure to mark the polarity on the U-clamp battery holders;
Connect the battery holder terminals to the input terminals of the TP4056 charging module according to the polarity;
Connect the modules so that they can transfer power from one stationary charger;
Also, make connections between switches so that they can be used to independently control the power of the modules.

Step 5: Testing the charger

Insert the batteries into the battery holders on the board;
Connect your charger mobile phone to one of the modules and turn on the power;
An indicator will glow on the module to indicate charging;
Use the switches to control the power supplied to the batteries;
Turn off all switches if you only want to charge one battery;
Turn on the switches according to the number of batteries charged at a certain time;
Since each battery has a separate charger, so they will never have the problem of overcharging and recharging (the most common problem that damages Lithium Ion cells).

Note: The TP4056 charging module is capable of providing 1A at 5V. Since we made a 4 battery charger, it is necessary to use a 2A mobile charger such that at least 500mA provides each cell.