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, could overheat greatly if it was charged incorrectly 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 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
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 the 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.
Often, novice drivers have a question about why the battery heats up when charging and how normal it is. When inside the body of the car’s battery, or seething begins, and it begins to heat up, for beginners, this may lead to the idea that something is wrong with the battery. Also, mobile phone owners are worried that the mobile phone "heats up a lot" when it is connected to the network. In fact, not always the heating of the battery during charging means its malfunction.
In order to dispel fears about the heating of car and phone batteries, consider some of the reasons why this can occur (by the way, it would be strange, on the contrary, if the batteries did not heat up at all during charging).
Reinsurance: we charge the car battery efficiently and correctly
You need to be aware that if the battery heats up during charging, this is a completely natural phenomenon, especially when the process comes to an end. To avoid overheating, it is important to monitor the battery at all stages of its charging - in much the same way as we watch a pot put on fire or any electrical appliance.
Toward the end of charging, do not leave the battery unattended for a long time. If it starts to heat up too much, it is better to reduce the current. Of course, the charging time may increase, but this is what will allow you to minimize possible risks.
Also, if your battery is old, it's important to keep in mind that older car batteries heat up faster and more often to avoid short circuits. Handle the old battery as carefully and carefully as possible.
Possible factory defect of a new battery
For novice drivers, it will not be superfluous to find out that the battery boiling process itself can tell why it gets very hot and for what reasons its total voltage indicator does not meet the required norm.
For example, when one of the cans closes due to a factory defect, boiling as a normal and natural process occurs in all serviceable battery compartments . There is no boiling process in a closed jar. When measuring the electrolyte density, its value in the "dead" compartment does not exceed 1.10 g/cm 3 . A battery with such a defect will produce a voltage of about 10.5 volts, and not the prescribed 12-13 at rest. It is better not to try it, but to return it back to the store, or exchange it for a serviceable one.
Possible problems if the battery is very "heated" when charging
In the event that you removed the battery from the car and put it in, and later found that it heats up more than necessary, the reasons can be quite understandable and sometimes fixable:
- The charger used is defective, or the currents are too high. Just try to reduce them.
- Something happened inside the battery itself. This may be damage to the plates, shedding or short circuit. The ability to fix the problem depends on the level of damage to the plates.
Why does the phone battery get hot when charging?
Most often, the concern of phone owners about this has no serious grounds:
- If the phone is charging, and there are no obvious signs of overheating, then charging can be safely continued: All mobile phones “heat up” when connected to the network .
- If you call, play games or text while charging your phone , its temperature will naturally be an order of magnitude higher than normal. In this case, you can wait for the device to finish charging so as not to worry again.
- If the body of your gadget is made of metal , it will heat up more, but there is no danger in this.
- When connected to a smartphone Wi-Fi or any kind of mobile internet downloading data will affect the temperature level while charging.
- The phone may get warm because of firmware errors (program code). In this case, try to find an updated firmware version on the Web.
- Checking the heating level of the smartphone during charging can be done using a utility like CPU-Z.
Thus, any battery heats up when charging. In the case of a car battery, it is important to carry out timely control of the process in order to avoid possible irreversible damage to it. If the phone heats up, most often the user's concern is in vain. But if there is any doubt, the level of battery heating during charging can always be checked using special programs.
In general, there can only be two situations:
- The battery seems to work, but it drains very quickly.
- The battery is dead and won't charge at all.
First situation: loss of capacity
In the first case, the battery capacity has dropped and you will have to put up with it. Full recovery of batteries after a deep discharge is impossible (this applies to all Li-ion batteries: 18650, 14500, 10440, batteries from mobile phones, etc.). Even theoretically, it is impossible to return the capacity of a lithium battery.
Decrease in capacity is an absolutely normal process. This happens during every charge/discharge cycle, no matter how well the battery is used. However, if deep discharges are often allowed during operation or, conversely, long overcharges (more than 500%), then the rate of capacity loss can increase significantly.
Recent studies have shown that lithium batteries lose their capacity even if they are not used at all. For example, during normal storage in warehouses. According to studies, the battery loses approximately 4-5% of its capacity per year.
Second situation: does not want to charge
Now consider the second case - the battery is not charging.
Usually this situation occurs when a device (phone, tablet, mp3 player) has been idle for a long time with a dead battery. Or if the lithium battery has undergone deep cooling.
In principle, there should be no problems with charging such batteries. Inside each battery - between the battery bank itself and the terminals that we see - there is a protection module that disconnects the bank from the terminals when the voltage drops below a certain threshold. Outwardly, this manifests itself as a complete absence of voltage at the battery output (zero volts).
In fact, as a rule, the voltage on the bank itself at this moment is about 2.4-2.8 Volts.
In the event of a battery blocking due to overload (short circuit in the load), the protection module also blocks the FET1 transistor. There is no difference from what the protection worked - from overdischarge or from a short circuit. There is only one result - an open transistor FET2 and a closed field worker FET1.
Thus, when deep discharging, the lithium-ion battery protection board does not prevent the battery from charging in any way.
The only problem is that some chargers consider themselves too smart and when they see that the battery voltage is too low (and in our case it will be zero at all), they consider that some kind of unacceptable situation has occurred and completely refuse to issue a charger. current.
This is done for security purposes only. The fact is that with an internal short circuit of the battery, it becomes dangerous to charge it - it can overheat and swell (with all sorts of special effects like electrolyte leakage, tablet cover extrusion, etc.). In the event of a break inside the battery, it becomes completely pointless to charge it. So the logic of such smart chargers is quite understandable and justified.
Read on to learn how to trick charging and restore the performance of a lithium battery after a deep discharge.
How to force it to charge?
In fact, the restoration of lithium-ion batteries after a deep discharge comes down to returning it to normal operation. It must be understood that this in no way compensates for the loss of capacity (this is impossible in principle).
In order to still force a too cunning charger to charge our very dead battery, it is necessary to make sure that the voltage on it exceeds a certain threshold. As a rule, 3.1-3.2 Volts is enough for the charger to consider the situation as normal and allow charging.
You can only raise the voltage on the battery with the help of a third-party (more stupid) charger. In the people it is called "push" the battery. To do this, simply connect an external power supply to the battery terminals, while limiting the maximum current.
For our purposes, any cell phone charger will do. Most often, modern chargers have an output in the form of a USB socket and, accordingly, give out 5V. We just have to pick up a resistor that limits the charge current.
The resistance of a resistor is calculated using Ohm's law. Let's take the worst-case scenario - the voltage on the internal bank of a lithium-ion battery is 2.0 Volts (we can't measure it without disassembling the battery, so we'll just assume that this is the case).
Then the difference between the power supply voltage and the battery voltage will be:
We calculate the resistance of the current-limiting resistor so that the charge current does not exceed 50 mA (this is quite enough for the initial charge and at the same time it is quite safe):
R = 3V / 0.050A = 60 Ohm
Now let's find out how much power will be dissipated on this resistor in the event of an internal short circuit of the battery (then all the voltage of the power supply will drop across the resistor):
P = (5V) 2 / 60 ohm = 0.42W
Thus, in order to restore the 18650 battery after a deep discharge, we take any 5V power supply, the nearest suitable resistor is 62 Ohm (0.5W) and connect it all to the battery as follows: 
A power source is also suitable for a different voltage, it will be enough to recalculate the resistance and power of the limiting resistor. And you need to remember that in li-ion protection circuits, as a rule, field-effect transistors with a small drain-source voltage are used, so it is undesirable to take a power supply with a high output voltage.
Reliable contact when connecting wires to the 18650 battery terminals will help to provide small neodymium magnets.
If the charge does not go(the resistor does not heat up, but the battery has the full voltage of the power supply), then either the protection circuit went into very deep protection, or it simply failed, or there is an internal break.
Then you can try to remove the outer polymer shell of the battery and connect our impromptu charger directly to the bank. Plus to plus, minus to minus. If in this case the charge did not go, then the battery is cranked. But if you went, then you need to wait until the voltage rises to 3+ Volts and then you can charge it as usual (with regular charging).
Of course, with the help of this device, you can fully charge the battery, but then you will have to wait a very long time (after all, the charge current is very small). In addition, in this case, you will have to very tightly control the voltage on the bank, so as not to miss the moment when it becomes 4.2V there. And, if anyone does not know, the voltage towards the end of the charge will begin to rise very quickly!
Now the situation is different- the resistor, on the contrary, noticeably heats up, but there is zero voltage on the battery, which means there is a short circuit somewhere inside. We gut the battery, solder the protection module and try to charge the jar itself. If it works, then the protection board is faulty and must be replaced. However, you can use the battery without it.
After removing the batteries from the packaging (blister), do not rush to put them in the charger in charging mode. It is better to insert new batteries into any suitable device and use until completely discharged. Only after they are completely discharged can they be fully charged.
I recommend "training" NiMH batteries at the very beginning of operation. For example, you can insert your new batteries into the TechnoLine BC-700 charger, photo on the right, and select the REFRESH mode ( capacity recovery). Thus, you will use the maximum capacity of the battery, as well as significantly extend the life of the battery.
How much current should NiMH batteries be charged?
Why does a finger battery get very hot when charging?
Strong heating of the battery during charging indicates that a very high charge current is set, or that the internal resistance in this battery is too high, and the service life is coming to an end. To prolong the life of your batteries, do not charge them unnecessarily with high current, provide forced cooling of the batteries if passive cooling is not enough. High temperature during charging negatively affects the chemical composition of the electrolyte, and leads to premature failure of the battery.
How to determine the charging time of a finger battery?
Determining the battery charging time is quite simple - look at the battery case, the ideal parameters for charging a particular battery are indicated there. But it is better to use such chargers that automatically determine the charge time for a particular battery. For example, the same TechnoLine BC-700. This charger determines the optimal charge time for each battery, that is, each inserted battery is charged autonomously; the process of charging a set of 4 batteries will not be interrupted if one of them charges faster.
Do I need to remove the battery from the charger immediately after charging?
For example, when charging 4 batteries, one battery charges faster. Do I need to take it out of the charger? Answer: no, you do not need to immediately remove it from the charger. You can safely leave it in the memory until the process of charging all the inserted batteries is completed.
Why does one battery take longer to charge from one package?
Obviously this is due to the fact that this instance has a higher capacity than the rest. In my practice, this is extremely rare, more often you can encounter the opposite situation, when one instance charges faster than the others. I advise you to quickly align this set of batteries in order to avoid possible problems with equipment that uses an unbalanced set.
What does it mean to align a battery pack?
This means the following:
First, you check (test), for example, 10 batteries for capacity. This can be done using analyzer chargers, which are described in detail. After you have a list of the received capacities of 10 batteries on hand, sort them according to the same (or approximately the same) capacity parameters. Thus, you should get at least two sets of batteries of different capacities, 4 pieces each.
How long should a NiMH battery last after being fully charged?
It depends on the type of battery, its capacity, maintenance / storage conditions and service life. For example, Duracell 2650mAh NiMH batteries will hold a useful charge for about a week (that is, charged and left on the shelf), after which they need to be recharged. But, for example, Sanyo Eneloop 2000mAh (LSD) will hold a useful charge for several years.
It is also important to properly maintain the battery in order to increase the storage time without recharging. For example, NiMH batteries need to be "trained" periodically, thereby restoring the working capacity.
What are LSD batteries?
LSD batteries (Low Self-Discharge) are such batteries that differ from other types of batteries by a low level of self-discharge. That is, after a full charge, these batteries are able to hold a useful charge for a long time (about 3 years).
What does "battery training" mean?
The term "battery training" is synonymous with the term "recovery of NiMH battery capacity". In common parlance, the term "acceleration of the battery" is also used, which is the same thing. These are cyclic discharge-charge stages of NiMH batteries that restore the lost battery capacity. Depending on the capacity of the battery, the state of the electrolyte, the charge / discharge current, there can be a lot of these cycles (discharge-charge), and they can also be different in duration.
