What is the charging current for 18650 lithium-ion batteries. Lithium-ion batteries: how to properly charge. Charging schemes for li-ion batteries

Today for mobile household appliances tools use special batteries. They differ in performance. In order for the battery to work for a long time, without failures, it is necessary to take into account the requirements of the manufacturers of the presented products.

One of the most popular types today are Li-Ion batteries. How to properly charge this type of battery, as well as the features of its operation, should be considered in detail before operating the device.

general characteristics

One of the most common types of batteries today is the Li-Ion type. Such devices are relatively inexpensive. At the same time, they are undemanding to operating conditions. In this case, the user rarely has a question about how to properly charge a cylindrical Li-Ion 18650 battery or another type.

Most often, the presented batteries are installed in smartphones, laptops, tablets and other similar devices. The presented accumulators are characterized by durability and reliability. They are not afraid of complete discharge.

One of the main features of the presented products is the absence of the "memory effect". These batteries can be recharged at almost any convenient time. The "memory effect" occurs when the battery is not fully discharged. If there is a small amount of charge left in it, the capacity of the battery will decrease over time. This will lead to an insufficiently long supply of equipment. In lithium-ion batteries, the "memory effect" is minimized.

Design

The design of a lithium-ion type battery depends on the type of device for which it is intended. For a mobile phone, a battery is used, which is called a "can". It has a rectangular shape and includes one structural element. Its nominal voltage is 3.7V.

A battery of the presented type for a laptop has a completely different design. There can be several individual battery cells in it (2-12 pieces). Each of them has a cylindrical shape. These are Li-Ion 18650 batteries. The manufacturer of the equipment indicates in detail how to charge them correctly. This design incorporates a special controller. It looks like a microchip. The controller manages the charging procedure, does not allow the nominal value of the battery capacity to be exceeded.

Modern batteries for tablets and smartphones also have a charge control function. This greatly extends battery life. It is protected from various adverse factors.

Charging features

Considering how to properly charge Li-Ion batteries of a phone, laptop and other equipment, you need to pay attention to the features of the presented device. It should be said that lithium-ion batteries do not tolerate deep discharge and overcharging. This is controlled by a special device that is added to the design (controller).

It is ideal to maintain the charge of the presented type of battery at a level of 20 to 80% of full capacity. The controller takes care of it. However, experts do not recommend leaving the device connected to charging all the time. This greatly reduces battery life. In this case, the controller is subjected to a constant load. Over time, its functionality may decrease due to this.

In this case, the controller will also not allow deep discharge. It will just turn off the battery at some point. This protective feature is essential. Otherwise, the user could accidentally overcharge or over-discharge the battery. Also in the batteries of a modern sample, high-quality protection against overheating is provided.

How the battery works

To understand how to properly charge a Li-Ion battery (new or used), you need to consider the principle of its operation. This will allow you to assess the need to control the level of discharge and charge of the device.

Lithium ions in a battery of the type presented move from one electrode to another. In this case, it appears electricity. The electrodes can be made from different materials. This indicator affects the performance of the device to a lesser extent.

Lithium ions grow on the crystal lattice of the electrodes. The latter, in turn, change their volume and composition. When the battery is charged or discharged, there are more ions on one of the electrodes. The higher the load on metal structural elements that lithium exerts, the shorter the life of the device will be. Therefore, it is better not to allow a high percentage of ion settling on one or the other electrode.

Charging Options

Before using the battery, you need to consider how to properly charge the Li-Ion battery of a smartphone, tablet and other equipment. There are several ways to do this.

One of the most correct decisions would be to use a charger. It is supplied with electronic equipment by each manufacturer.

The second option is to charge the battery from a desktop computer connected to a household network. For this, a USB cable is used. In this case, the charging procedure will be longer than when using the first method.

You can perform this procedure using the cigarette lighter in the car. Another less popular way is to charge a lithium-ion battery with universal device. It is also called "frog". Most often, such devices are used to recharge the batteries of smartphones. The contacts of this device can be adjusted in width.

Charging a new battery

The new battery must be properly commissioned. To do this, the phone, tablet or other equipment must be completely discharged. Only when the device is turned off can it be connected to the network. The controller will not let the battery drain too much. It is he who turns off the device when the battery loses capacity to a predetermined level.

Next, you need to connect electrical equipment to the network using a standard charger. The procedure is carried out until the indicator turns green. You can leave the device online for a few more hours. This procedure is carried out several times. At the same time, you do not need to specifically discharge your phone, tablet or laptop.

Normal charging

Knowing how to properly charge Li-Ion batteries can significantly extend battery life. Experts recommend to carry out the correct procedure for this process for a new battery. After that, it is not advisable to completely discharge the battery. When the indicator shows that the battery capacity is only 14-15% charged, it must be connected to the network.

At the same time, it is also not recommended to use other devices to fill the battery capacity, except for the standard one. It has the maximum acceptable current ratings allowed for specific model batteries. Other options should only be used if absolutely necessary.

Calibration

There is one more nuance that you need to know when studying the question of how to properly charge Li-Ion batteries. Experts recommend periodically calibrating this device. It is held every three months.

First, in normal mode, you need to discharge the electrical equipment until it is turned off. Then it is connected to the network. Charging continues until the indicator turns green (the battery is 100% charged). This procedure must be followed for the correct operation of the controller.

When carrying out such a procedure, the battery circuit board determines the limits for charging and discharging. This is necessary to ensure the normal operation of the controller, to avoid failures. In this case, the regular Charger, which is supplied by the manufacturer complete with a phone, tablet or laptop.

Storage

In order for the battery to last as long and efficiently as possible, you also need to consider how to properly charge the Li-Ion battery for storage. In some cases, a situation may arise when the device for powering equipment is temporarily not in operation. In this case, it must be properly prepared for storage.

The battery is charged up to 50%. In this state, it can be stored for a long time. However, the temperature environment should be around 15°C. If it rises, the rate at which the battery loses its capacity will increase.

If the battery is to be stored for a sufficiently long time, it must be completely discharged and charged once a month. The battery gains 100% of its specified capacity. Then the device is discharged again and charged up to 50%. With regular carrying out of this procedure, you can store the battery for a very long time. After that, it will be completely usable.

By considering how to properly charge Li-Ion batteries, you can significantly extend the life of this type of battery.

Lithium-ion batteries are used in modern mobile phones, laptops, tablets. Gradually, they forced out alkaline batteries from the portable electronics market. Previously, all of these devices used nickel-cadmium and nickel-metal hydride batteries. But their days are gone, as Li─Ion batteries have best performance. True, they can not replace alkaline ones in all respects. For example, the currents that nickel-cadmium batteries can produce are unattainable for them. For the power of smartphones and tablets, this is not critical. However, in the field of portable power tools that consume a lot of current, alkaline batteries are still in use. However, work on the development of batteries with high discharge currents without cadmium continues. Today we will talk about lithium-ion batteries, their design, operation and development prospects.

The very first battery cells with a lithium anode were produced in the seventies of the last century. They had a high specific energy intensity, which immediately made them in demand. Specialists have long sought to develop an alkali metal source that has a high activity. Thanks to this, the high voltage of this type of batteries and the specific energy were achieved. At the same time, the development of the design of such elements was carried out quite quickly, but their practical use caused difficulties. They managed to cope only in the 90s of the last century.

During these 20 years, researchers have come to the conclusion that the main problem is the lithium electrode. This metal is very active and during operation a number of processes took place, which eventually led to ignition. This came to be called flame ventilation. Because of this, in the early 90s, manufacturers were forced to recall batteries manufactured for mobile phones.

It happened after a series of accidents. At the time of the conversation, the current consumed from the battery reached its maximum and ventilation began with the ejection of the flame. As a result, there have been many cases of facial burns by users. Therefore, scientists had to refine the design of lithium ion batteries.

Lithium metal is extremely unstable, especially when charging and discharging. Therefore, the researchers began to create a lithium-type battery without the use of lithium. Ions of this alkali metal began to be used. That's where their name came from.

Lithium-ion batteries have a lower specific energy than . But they are safe if the norms of charge and discharge are observed.

Reactions taking place in a Li─Ion battery

A breakthrough in the direction of the introduction of lithium-ion batteries in consumer electronics was the development of batteries, in which the negative electrode was made of carbon material. The crystal lattice of carbon is very well suited as a matrix for the intercalation of lithium ions. To increase the battery voltage, the positive electrode was made of cobalt oxide. The potential of the printed cobalt oxide is approximately 4 volts.

The operating voltage of most lithium-ion batteries is 3 volts or more. During the discharge at the negative electrode, lithium is deintercalated from carbon and intercalated into cobalt oxide of the positive electrode. During the charging process, the processes occur in reverse. It turns out that there is no metal lithium in the system, but its ions work, which move from one electrode to another, creating an electric current.

Reactions at the negative electrode

All modern commercial models of lithium-ion batteries have a negative electrode made of carbon-containing material. The complex process of lithium intercalation into carbon largely depends on the nature of this material, as well as the electrolyte substance. The carbon matrix on the anode has a layered structure. The structure can be ordered (natural or synthetic graphite) or partially ordered (coke, soot, etc.).

During intercalation, lithium ions push the carbon layers apart, penetrating between them. Various intercalates are obtained. During intercalation and deintercalation, the specific volume of the carbon matrix changes insignificantly. In the negative electrode, in addition to the carbon material, silver, tin and their alloys can be used. They also try to use composite materials with silicon, tin sulfides, cobalt compounds, etc.

Reactions at the positive electrode

Primary lithium cells (batteries) often use the most different materials. In batteries, this cannot be done and the choice of material is limited. Therefore, the positive electrode of a Li─Ion battery is made of lithiated nickel or cobalt oxide. Lithium-manganese spinels can also be used.

Today, studies are underway on materials from mixed phosphates or oxides for the cathode. As specialists managed to prove, such materials improve the electrical characteristics of lithium-ion batteries. Methods for depositing oxides on the cathode surface are also being developed.

The reactions that take place in a lithium-ion battery during charging can be described by the following equations:

positive electrode

LiCoO 2 → Li 1-x CoO 2 + xLi + + xe -

negative electrode

C + xLi + + xe - → CLi x

During the discharge process, the reactions proceed in the opposite direction.

The figure below schematically shows the processes occurring in a lithium-ion battery during charging and discharging.

Lithium-ion battery device

According to their design, Li─Ion batteries are made in cylindrical and prismatic designs. The cylindrical design is a roll of electrodes with separator material to separate the electrodes. This roll is housed in an aluminum or steel casing. The negative electrode is connected to it.

The positive contact is displayed in the form of a pad on the end of the battery.

Li─Ion batteries of prismatic design are made by stacking rectangular plates on top of each other. Such batteries make it possible to make the packaging more dense. The difficulty lies in maintaining the compressive force on the electrodes. There are prismatic batteries with a roll assembly of electrodes twisted into a spiral.

All lithium-ion batteries are designed with measures to ensure their safe operation. First of all, this concerns the prevention of heating and ignition. A mechanism is installed under the battery cover that increases the resistance of the battery as the temperature coefficient increases. As the pressure inside the battery rises, allowable limit, the mechanism breaks the positive terminal and the cathode.

In addition, to increase the safety of operation in Li-Ion batteries, an electronic board is mandatory. Its purpose is to control the processes of charge and discharge, to exclude overheating and short circuits.

Many prismatic lithium-ion batteries are now being produced. They find application in smartphones and tablets. The design of prismatic batteries can often differ from manufacturer to manufacturer, since it does not have a single unification. Electrodes of opposite polarity are separated by a separator. For its production, porous polypropylene is used.

The design of Li-Ion and other types of lithium batteries is always sealed. This is a mandatory requirement, since electrolyte leakage is not permissible. If it leaks out, the electronics will be damaged. In addition, the sealed design prevents water and oxygen from entering the battery. If they get inside, they will destroy the battery as a result of reaction with the electrolyte and electrodes. The production of components for lithium batteries and their assembly is carried out in special dry boxes in an argon atmosphere. At the same time, they use complex tricks welding, sealing, etc.

As for the amount of active mass of a Li-Ion battery, manufacturers are always looking for a compromise here. They need to achieve maximum capacity and ensure the safety of operation. The relationship is based on:

A o / A n \u003d 1.1, where

A o is the active mass of the negative electrode;

And p is the active mass of the positive electrode.

This balance prevents the formation of lithium (pure metal) and eliminates ignition.

Parameters of Li-Ion batteries

Lithium-ion batteries produced today have a high specific energy intensity and operating voltage. The latter in most cases is from 3.5 to 3.7 volts. Energy intensity is from 100 to 180 watt-hours per kilogram or from 250 to 400 per liter. Some time ago, manufacturers could not produce batteries with a capacity higher than a few ampere-hours. Now the problems hindering development in this direction have been eliminated. So, lithium-type batteries with a capacity of several hundred ampere-hours began to be found on sale.

The discharge current of modern Li─Ion batteries ranges from 2C to 20C. They work in the range of ambient temperatures from -20 to +60 Celsius. There are models efficient at -40 Celsius. But it’s worth saying right away that special series of batteries work at negative temperatures. Ordinary lithium-ion batteries for mobile phones become inoperable at low temperatures.

The self-discharge of this type of battery is 4-6 percent during the first month. Further, it decreases and amounts to a percentage per year. This is significantly less than that of nickel-cadmium and nickel-metal hydride batteries. The service life is approximately 400-500 charge-discharge cycles.

Now let's talk about the features of the operation of lithium-ion batteries.

Operating lithium-ion batteries

Charging Li─Ion batteries

The charge of lithium-ion batteries is usually combined. First, they are charged at a constant current of 0.2-1C until they gain a voltage of 4.1-4.2 volts. And then charging is carried out at a constant voltage. The first step lasts about an hour, and the second about two. To charge the battery faster, use the pulse mode. Initially, Li─Ion batteries with graphite were produced and a voltage limit of 4.1 volts per cell was set for them. The point is that with more high voltage side reactions began in the cell, shortening the life of these batteries.

Gradually, these disadvantages were eliminated by alloying graphite with various additives. Modern lithium-ion cells charge up to 4.2 volts without problems. The error is 0.05 volts per cell. There are groups of Li─Ion batteries for the military and industrial sectors, where increased reliability and long service life are required. For such batteries, the maximum voltage per cell is 3.90 volts. They have a slightly lower energy density, but an extended service life.

If you charge a lithium-ion battery with a current of 1C, then the time for a full set of capacity will be 2-3 hours. The battery is considered fully charged when the voltage rises to maximum and the current drops to 3 percent of the value at the beginning of the charging process. This can be seen in the chart below.

The graph below shows the stages of charging a Li─Ion battery.

The charging process consists of the following steps:

• Stage 1. At this stage, the maximum charge current flows through the battery. It continues until the threshold voltage is reached;
• Stage 2. With a constant battery voltage, the charging current gradually decreases. This stage is terminated when the current decreases to 3 percent of the initial value;
• Stage 3. If the battery is put into storage, then at this stage there is a periodic charge to compensate for self-discharge. It is done approximately every 500 hours.
  It is known from practice that increasing the charge current does not reduce the battery charging time. As the current increases, the voltage rises faster to the threshold value. But then then the second stage of charging lasts longer. Some chargers (chargers) can charge a Li─Ion battery in an hour. In such memory there is no second stage, but in reality the battery at this point is charged somewhere by 70 percent.

As for jet charging, it is not applicable for lithium-ion batteries. This is because this type of battery cannot absorb excess energy when recharging. Jet recharging can lead to the transition of some of the lithium ions to the metallic state (valence 0).

A short charge well compensates for self-discharge and loss of electrical energy. Charging in the third stage can be done every 500 hours. As a rule, it is performed when the battery voltage drops to 4.05 volts on one element. The charge is carried out until the voltage rises to 4.2 volts.

It is worth noting the weak resistance of lithium-ion batteries to overcharging. As a result of applying an excess charge on the carbon matrix (negative electrode), the deposition of lithium metal can begin. It has a very high chemical activity and interacts with the electrolyte. As a result, oxygen evolution begins at the cathode, which threatens to increase the pressure in the case and depressurize. Therefore, if you are charging a Li─Ion cell bypassing the controller, do not allow the voltage to rise when charging higher than recommended by the battery manufacturer. If you constantly recharge the battery, its life will be shortened.

Manufacturers pay serious attention to the safety of Li-Ion batteries. The charge stops when the voltage rises above the allowable level. A mechanism is also installed to turn off the charge when the battery temperature rises above 90 Celsius. Some modern battery models have a mechanical type switch in their design. It is triggered by an increase in pressure inside the battery case. Voltage control mechanism electronic board disconnects the jar from the outside world by minimum and maximum voltage.

There are lithium-ion batteries without protection. These are models containing manganese in their composition. This element, when overcharged, contributes to the inhibition of lithium metallization and the release of oxygen. Therefore, in such batteries, protection becomes unnecessary.

Storage and discharge characteristics of lithium-ion batteries

Lithium-type batteries are stored quite well and self-discharge per year is only 10-20%, depending on storage conditions. But at the same time, the degradation of the battery cells continues even if it is not used. In general, all electrical parameters of a lithium-ion battery may differ for each specific instance.

For example, the voltage during discharge varies depending on the degree of charge, current, ambient temperature, etc. The battery life is affected by currents and modes of the discharge-charge cycle, temperature. One of the main drawbacks of Li-Ion batteries is their sensitivity to the charge-discharge mode, which is why they provide many different types of protection.

The graphs below show the discharge characteristics of lithium-ion batteries. They consider the dependence of voltage on the discharge current and ambient temperature.

As can be seen, as the discharge current increases, the capacitance drop is insignificant. But at the same time, the operating voltage is noticeably reduced. A similar picture is observed at temperatures below 10 degrees Celsius. It is also worth noting the initial voltage drop of the battery.

Progress is moving forward, and lithium batteries are increasingly replacing the traditionally used NiCd (nickel cadmium) and NiMh (nickel metal hydride) batteries.
With a comparable weight of one element, lithium has large capacity, in addition, their cell voltage is three times higher - 3.6 V per cell, instead of 1.2 V.
The cost of lithium batteries has begun to approach conventional alkaline batteries, the weight and size are much smaller, and besides, they can and should be charged. The manufacturer says 300-600 cycles can withstand.
There are different sizes and choosing the right one is not difficult.
The self-discharge is so low that they lie for years and remain charged, i.e. the device remains operational when it is needed.

"C" stands for Capacity

Often there is a designation of the form "xC". This is just a convenient notation for the charge or discharge current of a battery in fractions of its capacity. It is formed from the English word "Capacity" (capacity, capacity).
When talking about charging with a current of 2C, or 0.1C, they usually mean that the current should be (2 × battery capacity) / h or (0.1 × battery capacity) / h, respectively.
For example, a battery with a capacity of 720 mAh, for which the charge current is 0.5C, must be charged with a current of 0.5 × 720mAh / h = 360 mA, this also applies to the discharge.

And you can make yourself a simple or not very simple charger, depending on your experience and capabilities.

Diagram of a simple charger on the LM317

Rice. 5.

The circuit with the application provides a fairly accurate voltage stabilization, which is set by the potentiometer R2.
Current stabilization is not as critical as voltage regulation, so it is enough to stabilize the current using a shunt resistor Rx and an NPN transistor (VT1).

The required charging current for a particular lithium-ion (Li-Ion) and lithium-polymer (Li-Pol) battery is selected by changing the resistance Rx.
The resistance Rx approximately corresponds to the following ratio: 0.95/Imax.
The value of the resistor Rx indicated in the diagram corresponds to a current of 200 mA, this is an approximate value, it also depends on the transistor.

It is necessary to provide a radiator depending on the charge current and input voltage.
The input voltage must be at least 3 volts higher than the battery voltage for normal operation of the stabilizer, which for one bank is? 7-9 V.

Diagram of a simple charger on the LTC4054

Rice. 6.

You can desolder the LTC4054 charge controller from the old cell phone, for example, Samsung (C100, C110, X100, E700, E800, E820, P100, P510).

Rice. 7. This small 5-leg chip is labeled "LTH7" or "LTADY"

I will not go into the smallest details of working with the microcircuit, everything is in the datasheet. I will describe only the most necessary features.
Charge current up to 800 mA.
The optimal supply voltage is from 4.3 to 6 Volts.
Charge indication.
Output short circuit protection.
Overheating protection (reduction of charge current at temperatures above 120°).
Does not charge the battery when the voltage on it is below 2.9 V.

The charge current is set by a resistor between the fifth output of the microcircuit and ground according to the formula

I=1000/R,
where I is the charge current in amperes, R is the resistance of the resistor in ohms.

Lithium battery low indicator

Here simple circuit, which lights the LED when the battery is low and its residual voltage is close to critical.

Rice. eight.

Transistors are any low-power ones. The ignition voltage of the LED is selected by a divider of resistors R2 and R3. It is better to connect the circuit after the protection unit so that the LED does not drain the battery at all.

The nuance of durability

The manufacturer usually claims 300 cycles, but if you charge lithium just 0.1 volts less, up to 4.10 V, then the number of cycles increases to 600 or even more.

Operation and Precautions

It is safe to say that lithium-polymer batteries are the most “gentle” batteries in existence, that is, they require mandatory compliance with a few simple but mandatory rules, due to non-observance of which troubles happen.
1. Charge to a voltage exceeding 4.20 volts per can is not allowed.
2. Do not short circuit the battery.
3. It is not allowed to discharge with currents exceeding the load capacity or heating the battery above 60 ° C. 4. A discharge below a voltage of 3.00 Volts per jar is harmful.
5. Battery heating above 60°C is harmful. 6. Battery depressurization is harmful.
7. Harmful storage in a discharged state.

Failure to comply with the first three points leads to a fire, the rest - to a complete or partial loss of capacity.

From the practice of many years of use, I can say that the capacity of the batteries changes little, but the internal resistance increases and the battery starts to work less in time at high consumption currents - it seems that the capacity has fallen.
Therefore, I usually put a larger capacity, which the dimensions of the device allow, and even old cans, which are ten years old, work pretty well.

For not very high currents, old cell batteries are suitable.

You can pull out a lot of perfectly working 18650 batteries from an old laptop battery.

Where do I use lithium batteries

I have long converted a screwdriver and an electric screwdriver to lithium. I use these tools on a regular basis. Now even after a year of non-use, they work without recharging!

I put small batteries in children's toys, watches, etc., where there were 2-3 "tablet" elements from the factory. Where exactly 3V is needed, I add one diode in series and it turns out just right.

I put in LED flashlights.

Instead of the expensive and low-capacity Krona 9V, I installed 2 cans in the tester and forgot all the problems and extra costs.

In general, I put it wherever it turns out, instead of batteries.

Where do I buy lithium and usefulness on the topic

Are on sale. At the same link you will find charging modules and other useful things for DIYers.

At the expense of capacity, the Chinese usually lie and it is less than written.

Honest Sanyo 18650

How to properly charge a Li-Ion battery and significantly extend the life of 18650 batteries. What current can charge a Li-Ion 18650 battery?

Batteries of this size have several important indicators:

• capacity (mAh - mAh)
• discharge current (A)
• charge current (A)
• maximum number of discharge cycles

In this article, I will tell you about the last option and how this information can help you extend the life of your batteries.

Step 1: Full discharge cycles

What is a cycle?

When a battery is charged and then discharged, this is considered one cycle.

1. When charging Li-ion 18650 batteries, the voltage rises to a maximum of 4.2 V, then drops to a range between 2 and 3 V, depending on the technical description specific cell limiting charge voltage.
2. Do not allow less than 3 V to save battery life. This happens with any process that requires battery power. These processes require current, which is provided by the battery, so it is discharged. Test equipment can also be used for discharge.
3. Use a dedicated charger to charge 18650 Li-ion batteries.
4. How is the number of cycles calculated? The maximum number of full discharge cycles is determined by the difference between the capacity at the first charge (nominal) and the current charge level. For example, your phone was originally charged up to 3000 mAh, and now it is charging up to 2900 mAh, that is, up to 96% of the nominal capacity.
5. When this figure drops to 80%, the battery is said to have "died" (even if it actually survives a couple of thousand more cycles).

• For a 3000 mAh battery, conditional “death” occurs at 80% of the nominal capacity.
• 80% of 3000 - 2400, so when the battery capacity drops to this value, it will be considered "dead".
• Number of full discharge cycles for 18650 batteries
• Typically, modern batteries of this size have a number of cycles from 300 to 500. This number can drop to 200 from overcharging or deep discharge. If the charge level falls below the minimum limit (A), the number of cycles can drop up to 50.
• Under optimal operating conditions, the number of cycles of your battery can exceed 500.
• Some manage to increase this number as much as 1000.

Step 2: Optimize the temperature

Deviation from these figures entails a drop in the ability to hold a charge. A deviation of 10°C reduces the capacity by 20 or even 30 mA/h.

Extreme temperatures (below 0° and above 70°C) lead to rapid degradation. Operating the battery at temperatures outside the specified limits will quickly damage the battery.

Never charge batteries at temperatures below 0, this will destroy the battery structure very quickly.

If you notice that the battery becomes hot while using it, let it rest. During normal use, the battery will not get very hot and its temperature will never rise above 60°C. If it heats up quickly, then you're putting too much pressure on it.

Step 3: Do not overcharge the battery (above 4.2V) or let it go into deep discharge (below 4.0V)

If you care more about cycle life than capacity, then you may not be able to fully charge your battery.

Instead, you can charge it with a partial charge method - when you charge it, for example, to 3.8 V instead of the prescribed 4.2 V.

You will notice that the capacity has decreased, but if you reduce the load as well, then the number of cycles of your battery will increase. Overcharging will increase the capacity of the battery, but it is dangerous and will shorten the life of your battery.

Step 4: Reduce the charging current (Amps)

Many chargers reduce the charging current. "Fast charging" takes place at a current of 1 A, or higher. Although the battery charges faster this way, it will last you much less. The graph shows how the charging current affects the number of full discharge cycles.

Step 5: Reduce Discharge Current (Amps)

When discharging the phone, as mentioned above, you can set the voltage limit. But you can also set the discharge current amperage. The higher the amperage, the lower the capacitance.

High current discharge will also reduce the number of discharge cycles. Discharge the battery at low current whenever possible. All major electronics companies routinely run discharge tests at as little as 0.5-0.8A.

Step 6: Increase the voltage limit

A logical continuation of the partial charge method is partial discharge. The partial discharge cycle, unlike the full discharge cycle, is little known. Its advantage is that by reducing the load on the battery, the number of charge cycles increases.

Instead of discharging to 2.8V (or the value listed on your battery datasheet), you can discharge the battery to 3.2V.

Step 7: A little about battery chemistry

Batteries perform differently depending on their chemistry. Under optimal operating conditions, many 18650 cans can achieve cycle counts of 1000 or more.

The 18650 type Lithium-Ion batteries with the highest number of discharge cycles are LiFePO4 (Lithium Iron Phosphate batteries).

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 generate 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. 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 may have overheated if not charged properly or for too long. In this case, a short circuit and even a fire could occur, 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 maximum level 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

There is a simple technique on 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 (once every three months) it is possible to carry out complete 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.