18650 battery: characteristics and types, charging methods, application and repair

Polarity of 18650 battery Li-ion batteries 18650, 14500, etc. They look very similar to a AA battery.

For a lithium-ion battery, everything is the same, only the protrusion (positive contact) is slightly wider in diameter than in a battery. There are also small holes around the positive contact of the battery. The negative pole is as flat as in a battery.

In general, if you see holes around the pole, it is 100% positive, plus, (+).

In this case, we consider a lithium-ion battery without protection. The protected battery bank looks exactly the same, only it will be longer in length by the thickness of the protection board.

In addition, like most batteries, lithium ions have indications on the case where there is a plus and a minus.

A multimeter or tester (digital voltmeter) will also help determine the polarity. When measuring voltage, bringing the red probe to the positive contact and the black probe to the negative, the voltage in the bank will appear on the screen. If the red probe is brought to the negative contact, “-” (minus) will appear on the screen in front of the voltage value.

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

Types and types of Li Ion 18650 batteries

All 18650 batteries can be divided into types based on cathode material. The main operational characteristics of batteries depend on this component: capacity and possible discharge current.

The most common are lithium-cobalt batteries. They differ from other batteries in their large capacity. Therefore, they can be used longer.

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

The last group is lithium ferrophosphate batteries. Although they do not have a large capacity or high voltage, they can be operated for more than 1000 cycles. In addition, until fully charged, you need to keep the batteries in the station for 1 hour.

Deciphering the battery code

Each 18650 battery has a standard marking, according to which all parameters are determined by analyzing the information:

• Brand and country of production;
• Capacity indicator;
• Current strength;
• Rated cold current voltage;
• Type of chemical element;
• Polarity of contacts (not for all models);
• Date and year of issue;
• Charge level in symbols or letters (from the best manufacturers).

In appearance, the 18650 resembles a regular galvanic AA AA battery, differing from it in the chemical composition of the energy-intensive element. The class of the battery, the degree of current output, and the operating voltage depend on this composition. In total, three types of lithium-ion (Li-ion) batteries are produced with various combinations of auxiliary substances:

1. Low current - permissible current output up to 5A. These cells usually contain lithium ferrophosphate base (LiFePO4), manufacturer code on such batteries, for example, LG ICR18650D-1, Samsung ICR18650-26FM.
2. Medium current - for devices with consumption up to 10A. The chemistry of such batteries is lithium-manganese (LiMnO2), and is marked in the brand code: Samsung INR18650-35E, or LG INR18650MJ.
3. High current - with high output over 10A for more powerful devices. They contain lithium cobalt (LiCoO2), which is marked in the code as APR - SONY US18650VTC4.

The digital symbols of the 18650 battery mean: the first two numbers (18) are the diameter, the next two (65) are the length, then (0) the cylindrical shape of the element.

18650 batteries with protection

Safety requirements for the operation of lithium-ion batteries state that the voltage inside the batteries must be in the range of 2.5-4.2 volts. It is very difficult to control this parameter on your own, so a board with protection was invented specifically for this. This element prevents the voltage from going beyond the specified range.

Manufacturers solder this board to the pins using steel or aluminum tape. Large nutrient factories rarely produce such protections. The devices for which they are manufactured have charge-discharge controllers. These are batteries for laptops, screwdrivers and other complex units.

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

It is better to equip all devices that do not have an element for monitoring the battery status with protected batteries. Otherwise, they may fail, discharge to zero or explode. In this case, the protection will not be able to prevent the battery from overheating. It controls the state of tension.

Main nuances

How to properly insert the battery into the mech mod? Simple enough. All you need to do is unscrew the top part of the mechanical mod and place the purchased battery inside the structure. It is worth emphasizing that there is no insulator inside the battery compartment; the mechanical mod device is an ordinary steel cylinder. The power source must be inserted in such a way that its inserted plus does not come into contact with the minus of the atomizer. This stage of replacing the battery is not difficult. The next question is much more important.

How to choose the right battery for a vaping device so that it lasts as long as possible? Let's start with the fact that the device allows the coil to receive as much current as it requires for maximum heating. I think we mentioned that these atomizers do not provide any boards or settings for limiting power consumption. What follows from this? Everything is very simple. Let’s assume that the atomizer has a coil with a resistance of 0.1 Ohm and a power source of 4.2 Volts. Thus, the heating coil will require a current of 42 amperes and receive a power of 176 W. Amazing data.

This begs the following question: what will happen to the battery, how long does it last during active vaping? This circumstance depends on two factors:

• quality of power source;
• its purpose.

A “battery” that is not intended for these purposes may burst in the hand, which will lead to injuries and burns.

How to prevent this? Everything is elementary. It is necessary to choose a proven battery with suitable current output. But that's not all. Steamers would do well to remember Ohm's law. This is the only way you will be able to choose a battery for the atomizer that will provide you with thick and rich clouds of vapor during the process of evaporating the liquid. The information below will help you understand the simplest laws of physics. Let's dive into the world of current, voltage and resistance.

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How the marking is deciphered

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

1. The first symbol “I” is used on all elements of this type that 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, this can be cobalt - C, manganese - M, iron phosphate - F;
3. The next letter – R – stands for battery;
4. The 18650 numbers can be divided into two blocks: 18 and 65. These are the length and diameter, respectively;
5. The last digit 0 is the shape, that is, the cylinder.

At the same time, the markings of different manufacturers may vary greatly.

Marking of lithium batteries 18650

There are markings on the surface of the battery case. Here you can find complete information about the technical properties. In addition to the manufacturing date, expiration date and manufacturer's brand, the device of 18650 lithium batteries and the consumer qualities associated with this aspect are encrypted.

1. ICR – lithium-cobalt cathode. The battery has a high capacity, but is designed for low current consumption. Used in laptops, video cameras and similar long-lasting equipment with low energy consumption.
2. IMR – lithium manganese cathode. It has the ability to produce high currents and can withstand discharge up to 2.5 a/h.
3. INR – nickelate cathode. Provides high currents, withstands discharge up to 2.5 V.
4. NCR is a specific marking of Panasonic. The properties of the battery are identical to the IMR. Nickelates, cobalt salts, and aluminum oxide are used.

Positions 2,3,4 are called “high-current”, they are used for flashlights, binoculars, and cameras.

Lithium ferrophosphate batteries have the ability to operate at deep minus temperatures and are restored during deep discharge. Undervalued on the market.

By the marking you can determine whether this is a rechargeable lithium battery with the letters I R. If there are letters C/M/F, the cathode material is known. The capacity indicated will be mA/h. The release date and expiration date are located in different places.

You should know that manufacturers of rechargeable lithium batteries do not have products with a capacity of more than 3,600 mAh. In order to repair a laptop battery or assemble a new one, you need to purchase batteries without protection. To use a single copy, you need to buy elements with protection.

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 on average about 40 grams.

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

How to choose the right 18650 battery for yourself

Lithium-ion batteries differ from each other in several characteristics. 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 need to pay attention to the following characteristics:

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

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

The battery voltage depends on the charge. Voltage can be nominal, minimum, maximum and real. The manufacturer indicates the initial voltage on the packaging. It is important that its value does not fall below 2.4 Volts, otherwise the battery will be extremely difficult to revive. If you use batteries that do not withstand high temperatures well, you may experience an explosion.

Battery rating based on operating experience

Electronic protection boards

In addition, how to identify a Li-Ion battery with reverse polarity, you need to be able to distinguish between cells with and without protection boards. Protected cells have a safety valve to relieve high internal vapor pressure in case of incorrect use. To do this, a controller is attached to the contact of an unprotected battery by spot welding - a board that prevents overcharging, overheating and other dangerous situations when using a battery and connecting it to a charger.

If there is an electronic protection board, changing the polarity does not entail dire consequences - the battery simply does not charge or does not power the device. But in the absence of a protective board, any overheating of the cell entails destruction of the internal structure, so there is a risk of fire and explosion of the battery with incorrect polarity.

Protected batteries are slightly longer (1–3 mm) and usually have the designation “Protected”, “With protective PCB” or “Protection Circuit” on the case. Models without protection do not have such markings or are marked Unprotected. The dimensions of unprotected models strictly correspond to the standard ones - diameter 18 mm, height 65 mm.

We offer for your information an article on choosing batteries for power tools.

Battery connection diagrams

You can purchase cases for batteries, with the help of which several elements are combined into one large one. If you connect several of these batteries using cases in parallel, the capacity will increase by as much as the number of batteries that are 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.

Parallel connection of 18650 batteries

They can be connected in series. In this case, the voltage will add up, and the capacity will remain equal to one battery. This can be done using a special case. By connecting 3 3.7 V batteries we get an 11.1 volt 3600 mAh battery.

Series connection of 18650 batteries

Main characteristics

ONE of the most important parameters of a battery is its electrical capacity. Simply put, it is the amount of current that a battery can deliver per unit of time. It is measured in amperes per hour - Ah. The greater the electrical capacity, the easier it is, for example, to crank the starter in the cold. As a rule, automakers indicate what battery capacity is optimal for a particular car model. If it is insufficient, expect troubles associated with uncertain engine starting, frequent discharges and shorter battery life. If the capacity is excessive, the battery may constantly be undercharged, which is also not good for it.

However, not all so simple. Sometimes it makes sense to make allowances for the operating conditions of the machine. For example, if you live in an area with a cold climate, where there is severe frost in winter, then experts advise installing a battery with a capacity of 5-10 Ah more than the recommended parameters. This is also useful in the case when the car is equipped with a powerful audio system and is full of options such as various electric drives, heated seats, etc.

Another important characteristic is the starting current (it is measured in amperes) - it shows how efficiently the battery can power the engine starter. Again, in unfavorable conditions, for example in severe cold, the higher the current, the easier it is to start the engine. But this does not mean that on the eve of winter you should install a model with a higher starting current than recommended by the car manufacturer. At the very least, you should first consult with specialists - after all, if the current is too high, you can damage the starter.

Another parameter is the battery voltage, which is the same as the voltage of the car’s on-board network. For the vast majority of cars, it is 12 V. However, there are exceptions - for example, for large American pickups it can be 24 V. In any case, before installing a new battery, you should make sure that the voltage of the network and the battery match each other.

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 capacitance using the free method, you need to use a known current. The battery specifications contain information about the current. A battery with 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 is required for a full charge, you can find out the capacity.

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

Current output

Everything is very clear about the composition and size of energy carriers. Now let's look at the next important issue - current output. If the resistance of your evaporator requires 30 - 34 A or more, what should you do in this case? Current output is a very important characteristic of a battery. This data shows how much current the battery can safely deliver. For this purpose, there are markings for the so-called peak current output. If this data is not displayed on the energy carrier label, we look for a marking with the C value. For example, 1C with a maximum capacity of 2100 mA indicates that this type of energy carrier has a peak current output of 2.1 A. If any marking on battery is missing, in this case it is better to refrain from using this type of energy carrier.

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On the modern market you can purchase ten types of energy carriers for various devices - from laptops to flashlights. So, under no circumstances should these batteries be used in mechanical mods. They are absolutely not suitable for these devices. It is necessary to select energy carriers based solely on the above information. Pay attention only to brands from trusted and well-known manufacturers - this is the only way you can ensure your safety during the vaping process.

Take the issue of safety extremely seriously. Insert into the mechanical mod only batteries that have the required maximum power, in accordance with the resistance and voltage consumption data.

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How to charge and with what current

Lithium-ion cells can be charged at various stations. The main thing is that the voltage value is 5 V, and the current is from 0.5 to 1 of the nominal battery capacity. The lithium cell, which has a capacity of 2600 mAh, is charged with a current 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 capacity, charges for an hour. In this case, the voltage value varies between 4.1-4.2 volts. Then the tension increases.

In order not to bother yourself, you should just buy a charger for AA batteries.

Which 18650 lithium batteries are better on Ali Express

If the cost and quality of a 18650 lithium battery is important to you, use the AliExpress resource. There are a lot of products here, from different manufacturers. The battery you are looking for is in demand and people like to counterfeit it. Therefore, it is necessary to know the main differences between a good model and a replica.

Be critical of the indicated capacity. Only the best manufacturers have achieved 3,600 A/h, the average ones have an indicator of 3,000-3,200 A/h. The protected battery is 2-3 mm longer and slightly thicker than the unprotected one. But if you are assembling a battery, protection is not needed, do not overpay.

High-quality products are more expensive here too. Please note that Ultrafire promises 9000 mAh, but in reality it turns out to be 5-10 times lower. It is better to use a product from a trusted manufacturer, and try to always buy the same brand of battery.

We suggest you look at the procedure for restoring a 18650 lithium battery

How to restore a 18650 battery

An 18650 battery can only be restored if it is not completely discharged. Sometimes it is difficult to revive a battery that is not completely discharged. But there is one far from well-known option with disabling the board.

It is done like this:

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

If the battery starts charging, it means it is still alive and can be restored.

Still have questions about 18650 Batteries or have something to add? Then write to us about it in the comments, this will make the material more useful, complete and accurate.

Lithium-ion batteries of size 18650 have almost overtaken conventional AA batteries in popularity. They power a variety of devices, from electronic cigarettes to electric vehicles. They are more dangerous: if the lithium power supply is not installed correctly in the device, it can explode. Therefore, you need to know where the plus and minus of 18650 are, and in what ways you can find the poles.

What happens if you mix up plus and minus?

If you accidentally confuse a plus with a minus, you risk completely burning your device. Since it will start charging the wrong poles and the battery will almost immediately fail. It’s good if it just breaks, but there is a possibility that it will explode very strongly, and this can cause a serious fire in the house.

Note that modern chargers will not charge if the contacts are reversed, so we strongly recommend using them. It is better to overpay your funds once again than to take risks.

Methods for determining polarity

Since externally 18650 batteries are very similar to AA cells and the like, you can determine the polarity of the power source in the same way as in the case of a AA battery. There are two main ways to find plus and minus: by external inspection of the element or using any instrument that can measure the voltage at the poles.

By the appearance of the battery

The easiest way to determine the polarity of 18650 is to study the markings on the body of the product. On the sticker you can see all the necessary information, including:

• battery size;
• name of the manufacturing company;
• capacity in mAh;
• Rated voltage.

On high-quality elements, the polarity must be indicated - “plus” at one end and “minus” at the other. If there is no suspicion of erroneous labeling, you can safely rely on these icons. However, unscrupulous companies may not place polarity marks on their products. It is also possible to allow defective products to be sold - batteries on the housings of which the sticker is affixed on the wrong side, which is why the pole signs are reversed.

If you purchased a power source from an unknown manufacturer, you should additionally inspect its contact pads directly. Ideally, you should always do this to ensure maximum operating safety for 18650 batteries.

Like salt or alkaline batteries, the contacts of lithium-ion batteries differ in shape: the negative terminal is flat, while the “plus” terminal is convex. Additionally, lithium batteries typically have multiple holes on the positive terminal. They are needed to release the gas generated when the power source heats up. Thanks to this design, polarity can be determined not only by inspection, but also by touch.

How to distinguish polarity

This is what the positive terminal on the battery looks like:

There are several recommendations that will help you understand that this is a plus:

1. There are holes. As a rule, there are four of them, but in some modifications they may differ (they are extremely rare).
2. The plus always sticks out a little.
3. Plus cannot be flat.

The negative on the 18650 battery looks as shown in the photo:

As you may have noticed, it is flat. The negative contact does not have any bulges or holes, so be guided by this.