In this article I will show you how to make a simple Charger for these batteries.
Assembling and testing the charger.
We will need:
1. Syringe 20ml
2. 2 copper wires
3. Spring from a battery holder (from old equipment or toys)
4. 18650 lithium battery charging module on TP4056 5V 1A with micro USB interface ()
5. Hot melt adhesive
6. Rechargeable battery type 18650 ()
From the tools:
1. Soldering iron
2. Glue gun
3. Stationery knife
We will need a 20ml medical syringe and an 18650 battery.
The syringe fits perfectly to the size of the battery.
Using a utility knife, we cut off the nose of the syringe (where the needle is inserted) so that it does not interfere with our further use.
We take a spring from battery holders from old equipment (for example, from a remote control or toys).
We thread the copper wire into the hole from below and fasten it to the spring spiral as shown in the photo.
We take a 18650 lithium battery charging module on a TP4056 5V 1A with a micro USB interface and attach it with hot glue to a 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 3.7V lithium batteries with a current of up to 1A. This module, thanks to its size and micro USB connector, is easily integrated into various devices and can serve as an alternative replacement for failed lithium battery chargers. Supports various types of lithium batteries, including the popular 18650. The module is not protected from reverse polarity (non-polarity) connections, 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 secure the battery inside the syringe.
We make a hole in the syringe for the copper wiring so that it can touch the positive contact of the battery. The hole must be made at a level where the battery is not fixed by the syringe plunger. The photo shows that I mistakenly made one lower hole in the fixed position of the battery.
After inserting the wire into the hole and fixing the battery with the piston, you can begin testing the charger.
The charger works stably. 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 the low cost of consumables for a homemade charger and its simple design.
You can also make 20ml syringes and holders for this type of battery 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 compliance with a number of rules, but the main condition affecting the performance of 18650 lithium-ion batteries is their correct charging.
The main positive characteristics of 18650 lithium batteries are the ability to accumulate a large amount of charge, store this charge for quite a long time, the lack of memory properties and a meager 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:
At the initial stage of production and use, such batteries were explosive due to uncontrolled chemical reactions inside and cases of short circuits inside the batteries. To prevent such breakdowns, all rechargeable batteries in general and 18650 batteries 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 a temperature of 5°C with a 40% battery discharge.
Well-known charger manufacturers use a two-stage battery charging method.
The two-stage charging method includes:
In addition to the above-mentioned charging stages, a preparatory battery charge is applicable for 18650 li-ion batteries. Charging is carried out with a reduced current until the voltage on the battery reaches 2.8V.
Despite its indispensability, the two-stage charging system has some disadvantages. Since the voltage on the battery is measured while a large charging current passes through it, depending on the internal resistance of the battery, such measurements may vary. In this regard, the voltage can reach 4.3-4.4V, which has an extremely negative effect on the battery. In practice, it is better to use 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 the charger produces. Accordingly, when the measured voltage reaches 4.15V, the supply of pulses will stop.
Radio amateurs quite often wonder how to charge lithium-ion batteries and how to charge with maximum savings of resources, effort and time. The presence of the necessary element base and basic knowledge will not leave the radio amateur without a charger.
The assembled DIY 18650 charger, shown in the picture below, is adjusted by setting the output voltage to 4.2V with trimming resistor R8 and the charging current with resistors R4, R6. The charging process is considered complete after the HL1 LED goes out.
Important! For normal operation of the LM317 chip, charging for 18650 batteries must have an input voltage in the range of 8-12V.
Homemade charging for 18650, which contains MAX integrated circuits (1551 or 1555), is qualitatively different from its competitors in a number of properties and features:
It will not be difficult to obtain a pulse charger for 18650, assembled with your own hands, due to the absence 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 the element base with domestic analogues. A smart charger for 18650 batteries, assembled and tested with your own hands, will last no worse than the purchased charger.
The presented topic revealed the following questions: how to charge the battery, how to charge a li-ion battery. When using a charger for 18650 batteries, purchased or homemade, the main thing is to carefully check the output values. Next, you can pay attention to additional options in the form of LCD displays, the number of channels, the presence of backlight, and a car adapter.
Nowadays, 18650 type rechargeable batteries are very popular. They are used in power banks, powerful flashlights, laser pointers, portable speakers and for various homemade products. Sold with charger or separately.
In this article I will show you how to make a simple charger for these batteries.
Assembling and testing the charger for review.
We will need:
1. Syringe 20ml
2. 2 copper wires
3. Spring from a battery holder (from old equipment or toys)
4. 18650 lithium battery charging module on TP4056 5V 1A with micro USB interface ()
5. Hot melt adhesive
6. Rechargeable battery type 18650 ()
From the tools:
1. Soldering iron
2. Glue gun
3. Stationery knife
Step 1
We will need a 20ml medical syringe
Step 2
Using a utility knife, we cut off the nose of the syringe (where the needle is inserted) so that it does not interfere with our further use.
Step 3
We take a spring from battery holders from old equipment (for example, from a remote control or toys).
We thread the copper wire into the hole from below and fasten it to the spring spiral as shown in the photo.
Step 5
We take a 18650 lithium battery charging module on a TP4056 5V 1A with a micro USB interface and attach it with hot glue to a syringe in a convenient place.
Step 6
We cut off a small piece from the syringe piston at the base with an elastic band, as shown in the photo. This will secure the battery inside the syringe.
Step 7
We make a hole in the syringe for the copper wiring so that it can touch the positive contact of the battery.
The hole must be made at a level where the battery is not fixed by the syringe plunger. The photo shows that I mistakenly made one lower hole in the fixed position of the battery.
Step 8
After inserting the wire into the hole and fixing the battery with the piston, you can begin testing the charger.
Today you can see a wide range of different charging systems. Each is intended for a specific device. The 18650 charger is somewhat different from a similar device for charging acid batteries. The 18650 lithium battery has a high voltage of each cell.
Stores selling electrical equipment offer a huge range of chargers. The cheapest charger for a li ion 18650 battery provides a current of 1 ampere. The device is designed to charge one 18650 battery.
The industry is releasing an improved charging system designed to work with 18650 batteries. You can fit 2-4 cells at once here. The maximum voltage does not exceed 4.2 volts. The device has a high cost, since it is equipped with a charge controller that monitors the charge time and voltage.
For lovers of universal devices, charging for such batteries of different types is offered. This charger is capable of simultaneously charging nickel as well as 18650 lithium-ion batteries. Most modern chargers are equipped with a safety system that monitors the voltage as well as the charging current. Naturally, the higher the quality of the charger, the higher its cost.
Factory products initially supply a large current, gradually reducing its value. As a result, the product does not overheat, and the service life of the ion battery increases.
To charge four 18650 batteries at the same time, use the Nitecore Digicharger D4 charger. The device is equipped with an informative display showing useful information. The screen will display the charging time, charging speed, and cell voltage. Controlling the device makes it possible to switch between different compartments to read information about each battery being charged. The device belongs to the universal group, so it can charge batteries of various types.
The product automatically sets the charging time and regulates its speed. Unfortunately, the charger is not equipped with manual settings, which eliminates fine tuning. The device automatically completes the charging process of any battery.
Nitecore D4 will be the optimal device if there is a need for daily use. This is especially true for people who have several mobile devices with different types of batteries.
To charge 18650 batteries yourself, it is important to first study how electrical circuits work, as well as the parameters that allow charging the battery. Several methods are known.
The simplest option is to recharge the battery with a charger suitable for Samsung phones. The current and voltage of this charger are suitable for 18650 batteries.
The connection diagram is quite simple. The charger wires are released from the retaining sheath. The negative contact is determined, as well as the positive wire. The plus is always supplied with a red wire, the minus with a black wire. It's impossible to mix it up.
The bare contacts are connected to the battery, observing the polarity. The wires are fixed with ordinary plasticine. All that remains is to supply power and start charging, regularly monitoring the process. Within an hour, the capacity parameters will be completely restored.
Another method is designed to improve charging. But the connection diagram will be more complicated. To work you will need:
The most important element for a home device is the charging board. It is sold in online stores. Assembly is performed in a certain sequence. First, prepare a plastic box with wires (plus, minus). The charging board is soldered to it. The battery is inserted into the box, power is supplied, and charging begins. 
To use this option, it is important to select a box (container) whose dimensions correspond to the dimensions of the 18650 battery. The wires must be soldered to places specially marked on the board. To control the amount of charge, the board is equipped with several LED indicators of different shades (red, green).
The board is fixed to the box anywhere, allowing you to see the operation of the indicators. Then the wires are soldered, maintaining the polarity. The ends, before starting soldering, are thoroughly cleaned and then covered with rosin. Liquid flux is dripped onto the surface of the board (2-3 drops).
During soldering, the wires should not contact each other. You can assemble the described circuit yourself very quickly. It is inexpensive, but it is highly reliable and has an excellent charge. After applying voltage, all you have to do is look at the indicator. The green light indicates the battery charge strength.
When charging 18650 lithium batteries, a voltage of 5 V must be supplied at the output, a current value of 0.5 - 1A (taken from the minimum value of the battery capacity). In other words, a lithium battery with a capacity of 2600 mAh must be charged with a current in the range of 1.32.6 amperes. Manufacturers of chargers for such batteries produce devices that perform this process in several steps.
First, a current of 0.2 A is supplied. Moreover, the voltage of one can reaches 4.1–4.2 volts. This operation takes less than one hour. In the second stage, constant voltage is applied. To reduce charging time, production began to produce a charger with a pulse mode
Some lithium-ion batteries are equipped with a graphite electrode. In order for the charge to proceed normally, it is necessary that a voltage exceeding 4.1 volts be applied to each element. If we take a regular lithium battery, an increase in voltage will lead to an increase in energy density, and at the same time oxidative processes will begin to be active.
As a result, the service life of the lithium battery is sharply reduced. This phenomenon is not observed in batteries equipped with graphite electrodes. Oxidation is reduced by special additives. In other words, increasing the voltage in graphite batteries is not critical, but it is better not to do it.
If you start charging 18650 batteries at 1A, it will take approximately 2-3 hours to fully charge. During this time, the voltage will rise to a certain value. During operation, the charger quickly reduces the current by several percent (calculated from the original value). Increasing the charge current (more than 1 ampere) does not have a serious effect on charging time. The second stage of charging usually lasts much longer than at the very beginning.
The industry produces chargers that can fully charge a 18650 lithium battery in approximately one hour. These devices are not able to carry out the second stage; it is completely absent. At the initial stage, the battery is charged approximately 60–80 percent. Then it begins to be used in the device. Such a charge cannot be considered critical for lithium cells. On the contrary, they should not be fully charged, the battery should not be greatly discharged
Many people probably have a problem with charging a Li-Ion battery without a controller; I had this situation. I received a dead laptop, and there were 4 SANYO UR18650A cans in the battery that were alive.
I decided to replace the LED flashlight with three AAA batteries. The question arose about charging them.
After digging around on the Internet I found a bunch of diagrams, but details are a little tight in our city.
I tried charging from a cell phone charger, the problem is in charge control, you need to constantly monitor the heating, it just starts to heat up, you need to disconnect from charging, otherwise the battery will be damaged in the best case, otherwise you can start a fire.
I decided to do it myself. I bought a bed for the battery in the store. I bought a charger at a flea market. To make it easier to track the end of the charge, it is advisable to find one with a two-color LED that signals the end of the charge. It switches from red to green when charging is complete.
But you can also use a regular one. The charger can be replaced with a USB cord and charged from a computer or charger with a USB output.
My charger is only for batteries without a controller. I took the controller from an old cell phone battery. It ensures that the battery is not overcharged above a voltage of 4.2 V, or discharged below 2...3 V. Also, the protection circuit saves from short circuits by disconnecting the bank itself from the consumer at the moment of a short circuit.
It contains the DW01 chip and an assembly of two SM8502A MOSFET transistors (M1, M2). There are also other markings, but the circuits are similar to this one and work similarly.
Cell phone battery charge controller.
