Li-ion 18650 rechargeable batteries

The li ion 18650 battery is a cylindrical battery. It is not much different from ordinary AA batteries “finger-type”, but they are large. They are 66 mm in length and 18 mm in diameter.

Types and types of batteries Li Ion 18650

All 18650 batteries can be divided into types according to the cathode material. It is from this component that the basic operational characteristics of the batteries depend: capacity and possible discharge current.

The most common are lithium cobalt batteries. They differ from other batteries with a large capacity value. Therefore, they can be exploited longer.

There are still a group of lithium-manganese batteries. Compared with lithium-cobalt, they have a lower capacity, but at the same time they have a higher discharge current.

The last group is lithium-ferrophosphate batteries. Despite the fact that they do not have a large capacity and do not differ in high voltage, they can be operated for more than 1000 cycles. In addition, it is necessary to hold the batteries in the station for 1 hour until fully charged.

18650 batteries with protection

The safety requirements for the operation of lithium-ion batteries state that the voltage inside the batteries should be in the range of 2.5-4.2 volts. It is very difficult to independently control this parameter, therefore, a specially designed board with protection has been invented. This element prevents voltage out of the specified range.

Manufacturers solder this board to the terminals using steel or aluminum tape. Large nutrient plants rarely produce such defenses. In the devices for which they are manufactured, there are charge-discharge controllers. These are batteries for laptops, screwdrivers and other complex units.

The most protected 18650 lithium-ion batteries are manufactured by Chinese manufacturers. A protective board is soldered to an unprotected battery and wrapped in a special heat-protective material. Their length, due to the use of the board, increases by several millimeters.

All devices that do not have an element for monitoring the status of the battery are best equipped with protected batteries. Otherwise, they may fail, discharged to zero or explode. In this case, the protection will not be able to prevent overheating of the battery. It monitors the state of stress.

How labeling stands

As an example, consider the lithium-ion battery ICR18650-26F M.

1. The first character “I” is used on all elements of this type, which are created using the same technology;
2. The second letter allows you to understand what material the cathode is made of. For lithium-ion batteries, it can be cobalt - C, manganese - M, iron phosphate - F;
3. The next letter - R - stands for battery;
4. The numbers 18650 can be divided into two blocks: 18 and 65. This is the length and diameter, respectively;
5. The last digit 0 is the shape, that is, the cylinder.

At the same time, different manufacturers may mark different markings.

Where are 18650 batteries used?

The scope of the batteries and their frequency of use is much wider than it seems to many. Due to the fact that they close in special protection, they are not always visible.

Installed in the following devices:

• Laptops;
• Flashlights;
• Power Bank;
• Various gadgets.

They are used wherever ordinary finger batteries are unable to cope with the task. Li-ion 18650 batteries have a larger capacity and voltage, they can be recharged and reused many times.

How to determine plus and minus

Compared to AA and AAA batteries, lithium-ion does not have such a noticeable external difference between the plus and minus terminals, but it’s easy to understand:

• On the "plus" side there are small holes in the amount of 3-4 pieces.
• The "plus" side is a little protruding. "
• “The minus is completely flat.

General characteristics of 18650

The table shows the most popular batteries.

Dimensions with protection 66.5 * 18 mm and 66 * 18 mm without protection. Weight an average of about 40 grams.

Major manufacturers: Samsung, Fenix, Avant, LG, Panasonic, Olight, Camelion, Proconnect, Rombica, SANYO and SONY.

How to choose the right battery for yourself 18650

Lithium-ion batteries differ in some respects. Because of this, it is necessary to pay attention to their type and technical characteristics before making a purchase.

When choosing a li ion 18650 battery, you must pay attention to the following characteristics:

• Energy intensity;
• Rated current;
• Voltage
• Tendency to overheat.

If you need to buy batteries with greater autonomy, you need to pay attention to the capacity, which is measured in mAh. But, the higher the capacity indicator, the less current will be. Therefore, by sacrificing one, you can acquire another. In simple terms, the current strength affects the tendency of the battery to overheat.

Battery voltage depends on the charge. Voltage can be nominal, minimum, maximum and real. The manufacturer indicates the initial voltage on the package. It is important that its value does not fall below 2.4 Volts, otherwise the battery will be extremely difficult to reanimate. When using batteries that do not withstand high temperatures, you can witness its explosion.

Battery rating based on operating experience

Battery Connection Diagrams

You can buy cases for batteries, with the help of which several elements are connected into one big one. If you connect several of these batteries with cases in parallel, then the capacity will increase by as much as the batteries will be connected 3600 * 3 = 10800 mAh. In this case, the voltage will be equal to the voltage of one battery. The duration of their use depends on the capacity.

They can be connected in series. In this case, the voltage develops, and the capacity remains equal to one battery. This can be done using a special case. Connecting 3 batteries of 3.7 v each we get an 11.1 volt battery 3600 mAh.

How to check battery capacity

There are several effective ways to find out the capacity of any battery. Some of them do not require special expenses or special equipment, but only simple mathematical calculations.

The accuracy of such methods is not as high as when using special devices, but they allow you to find out the approximate capacity. For many, this will be enough.

So, to calculate the capacity by the free method, you need to use a known current. The battery specifications have current information. A battery having a capacity of 3600 is charged for 36 hours with a current of 100 mAh. This means that the final result is obtained by multiplying two components: time and current. Therefore, knowing how much it takes to fully charge, you can find out the capacity.

To measure capacity in another way, you will need to spend money. There are many smart chargers with which you can quickly measure capacity. They can be purchased at a specialty store or on aliexpress. They are used to measure various indicators, not just capacities.

To implement the third method, you will need such details as a battery, a clock, an ammeter with a flashlight. You must insert the battery into the flashlight, turn it on at maximum power. An ammeter is needed to measure current. If the flashlight shines for 20 hours with a current consumption of 100 mA, then we get 20 * 100 = 2000 mAh.

How to charge and what current

Lithium-ion cells can be charged by various stations. The main thing is that the voltage value is 5 V, and the current from 0.5 to 1 of the nominal battery capacity. A lithium cell having a capacity of 2600 mAh is charged with a current value of 1.3 to 2.6 amperes.

The entire charging period can be divided into several stages. First, the unit, using a current of 0.2 of the value of the capacitance, charges for an hour. In this case, the voltage value varies between 4.1-4.2 volts. Further, the voltage increases.

In order not to bother yourself, you just need to buy a charger for finger-type batteries.

How to restore a 18650 battery

The 18650 battery can only be restored if it is not completely discharged. It’s sometimes difficult to reanimate a battery that’s not completely discharged. But there is one far from universally known option with disabling the board.

It runs like this:

• The protection is removed in the form of a board.
• Using a tester, the voltage at the outputs is measured. Its value should be in the range of 2 -2.5 V.
• Using a charger with adjustable current, it is necessary to connect to the battery, setting 100 mA and 4.2V.

If the battery starts to charge, it means that it is still alive and can be restored.

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