How much does a 18650 lithium-ion battery weigh? Castration of protected Sanyo and Panasonic batteries and a small educational program on Li-ion. Deciphering markings and inscriptions on batteries

To answer the question of what the 18650 format battery is used for or what it is also called - 168A, let's study its characteristics and capabilities, as well as examples of use in domestic conditions.

This type of battery is currently is quite popular for a number of reasons, but the main ones are the voltage of 3.7-4.3 volts and good capacity (working time) up to 3600 mAh, as well as a fairly compact size.

They are similar in shape to AA-sized “finger” batteries and AAA-sized “pinky” batteries, but larger in size. As mentioned above, the output voltage of these batteries is 3.7 - 4.3V. Capacity is 2200-3400 mAh.

AA and AAA AA batteries have a voltage of 1.5V

At Ni-MH ( nickel-metal hydride) batteries of AA and AAA format - 1.2V.

Schematic device of a Li-ion battery

Li-ion battery capacity 18650

Energy capacity is the amount of energy that is stored in the battery. Battery capacity is often expressed in watt-hours (Wh), kilowatt-hours (kWh) or ampere-hours (Ah). The most common measure of battery capacity is Ah, defined as the number of hours that the battery can supply a current equal to the discharge rate at the battery's rated voltage. A watt hour is the voltage (V) that the battery provides multiplied by the amount of current (amps) the battery can provide for some time (usually in hours). Voltage*Ampere*hours = Wh. Since the voltage is highly dependent on the battery type due to its internal chemistry (alkaline, lithium, lead acid, etc.), often the battery side only displays amp hour data expressed in Ah or mAh (1000 mAh = 1 Ah). To get Wh, multiply Ah by the rated voltage. For example, suppose we have a nominal 3 V battery with a capacity of 1 Ah or 1000 mA*h, its power will be 3 W.

1 A*h means that theoretically we can use 1 ampere of current for one hour or 0.1A for 10 hours or 0.01A (10 mA) for 100 hours.

IMPORTANT! At the time of writing, there are NO batteries with a capacity higher than 3600 mAh in the 18650 size!!!

Battery size 18650

Decoding the digital designations of the 18650 battery:

the first two digits (18) – diameter;

the next pair of numbers (65) is the length;

the last digit (0) indicates the shape of the battery, in this case a cylinder.

As we can see after measurements, the length of the cheapest Chinese battery brand UltraFire (manufacturer of cheap Chinese flashlights) 18650 format is 66.5mm, and the diameter is 18mm.

Let's compare the sizes with other types of batteries:

AAA: 44.5 x 10.5 mm

AA: 50.5 x 14.5 mm

14500: 53 x 14.5 mm

18650: 65.5 x 18 mm (unprotected)

18650: 67.5 x 18 mm (protected)

26650: 67.5 x 26.1 mm

A visual comparison of AA, AAA and 18650 batteries.

And although the 18650 format battery resembles finger and little finger batteries, it will be larger in size.

What is a protected battery

18650 batteries come with and without protection - if the 18650 battery does not have protection, then it does not additional inscriptions, or the inscription “Unprotected” is present. Length of unprotected (without protection board full discharge or recharge) – 66.5 mm.

If the battery description contains the words “With Re/Discharging Protection Circuit” (protection from complete discharge/overcharge), “Protected”, “With protective PCB”, “Protection Circuit”, etc., then the battery has a protection board on board. A small thickening (usually a 1mm plate) near the contact is the battery protection board.

For reliable operation and to avoid damage, complete discharge or overcharging and overheating, Li-Ion batteries must operate within a voltage range of 4.2-2.5V.

One of the weak points of Li-ion batteries is that they are subject to failure during overcharging and/or overheating, as well as when they are completely discharged. After which it will be problematic to restore or charge the battery or it will lose its initial capacity. If handled carelessly, lithium-ion batteries can fail more often than other types of batteries.

This problem is solved, as noted above, by installing electronic circuit protection that prevents excessive overcharging and/or overheating as a result of exceeding the permissible current during charging, and also interrupts the circuit when the charge is low, protecting the battery from deep discharge during operation. This protection board not only ensures that the battery operates within the safe voltage range, but also prevents overcurrent and short circuits. The protection board is spot welded using a steel conductor to the corresponding battery contacts. In reality, it looks like this: an electronic protection board with a thickness of 1-3mm and the diameter of the battery is installed on the negative contact of an unprotected Li-Ion battery (“cell”).

The length of such a battery is slightly longer - on average 67.5-70mm versus 65-66mm for an unprotected one. When the battery voltage rises above 4.25V, the protection board blocks further charging of the battery to prevent it from being damaged by overcharging and overheating. The same thing happens when the voltage is less than 2.75V - the protection board blocks further discharge of the battery below the specified threshold.

Typically, large Li-Ion battery manufacturers do not produce batteries with built-in protection. They only produce unprotected batteries. As a rule, there are no protected Li-Ion batteries of the SAMSUNG or Panasonic brand, which would be released specifically by “Panasonic in Japan” or “Samsung in Korea”, and those who prove the opposite are intentionally or unintentionally trying to mislead you misleading.

Protected batteries are assembled from conventional Li-Ion batteries (cells) followed by installation of a protection board.

The assembly process can occur in different ways: as a rule, the battery assembly with protection is carried out at enterprises in China. But China is different - there are both outright counterfeits and amateurism on the part of little-known battery manufacturers (with imaginary capacities from 3800 mAh to infinity) and very high-quality products from well-known brands.

Protected batteries are assembled and sold by completely different brands that are not related to the manufacturer of the batteries themselves. A factory-assembled battery with protection is covered with a thermal shell with the brand name and an indication of the capacity (sometimes real and sometimes absolutely fantastic).

Due to the fact that a protected 18650 battery is 1-3 millimeters longer than its unprotected counterparts and sometimes 0.5 mm thicker in diameter.

Extended batteries with protection may have a standard size of 18700, and size always matters - such a battery may not fit into the battery compartment of some consumer devices. Therefore, when choosing a protected battery, you should think about whether it is the right length, for example, for your LED flashlight, charger, etc.

Mechanical - internal protection of Li-ion batteries

In addition to protection using a charge controller board, the battery can use an internal mechanical protection system for the battery. Function internal protection consists in the operation of a special mechanical switch as a result of the temperature threshold (overcharge/heating) and pressure inside the battery increasing to critical values, which can lead to an explosion. The battery is disconnected by mechanically breaking the circuit by the internal protection of the power source. If this does not help and the temperature and pressure continue to rise further, then the pressure relief valve is activated, which releases gases and electrolyte outside.

The mechanical switch itself is quite common as a primary or additional safety measure in many batteries, functioning in conjunction with or without a charge controller (board). It is worth noting that the presence of internal protection will not necessarily be mentioned on the case or in the description of the technical characteristics of the product. As a rule, well-known manufacturing companies will not neglect the internal mechanical protection of their power supplies with an unstable chemical composition, with the possible exception of the cheapest and little-known Chinese brands. Therefore, regardless of whether any power supply has or does not have an electronic protection board, it must have built-in physical protection.

Use of protected and unprotected Li-ion batteries

18650 batteries are usually used where long periods of time are required. battery life with a compact size.

Both unprotected and protected batteries can be used in any devices or devices designed to work with Li-Ion power sources, the only difference is that if the device or device do not have a built-in charge-discharge controller, then this disadvantage can be compensated for by a protected power supply.

The main devices that use Li-Ion batteries today are LED flashlights and lamps, since these batteries have sufficient power and capacity to ensure long-term and uninterrupted operation of the latest generation of powerful LEDs in these devices.

In our particular example, these are LED lights with diodes of the latest generations XM-L/L2, XP-L/L2, etc. (Convoy s2+, Convoy c8).

This flashlight contains AAA battery

This flashlight runs on AA battery

And these lights are equipped with the latest generations of LEDs CREE XM-L2, XP-L2. For their work it is necessary high power. That is why these flashlights are powered by an 18650 battery and are made for it, as it is ideal for these purposes.

Some flashlights from cheap Chinese brands such as UltraFire are designed in such a way that the 18650 battery can be replaced with 3 AA batteries through a special adapter. In this case, the voltage is almost the same: 3.7V and 4.5V (= 1.25V*3 or 1.5V*3).

In most cases, for simple Chinese LED flashlights such as UltraFire, a protected battery is required.

It happens that some batteries have too sensitive current protection and operate at less than permissible values. In this regard, flashlights using powerful LEDs of the latest generations XM-L/L2, XP-L/L2 do not function properly. When you turn on the flashlight, an overcurrent occurs - the battery protection is triggered, the flashlight may blink and no longer show signs of life. If you change the battery to an identical one, the same thing can happen; the protection is triggered instantly. There are two options - either remove the protection board and use the battery without it, or replace the battery with another one from a time-tested brand.

As mentioned above, battery protection definitely increases the length of the battery by 1-2 mm, or even more. If the Li-Ion battery with protection reaches a length of 7 cm, some compact flashlights designed to install Li-Ion batteries cannot be screwed in back cover and you have to look for a battery without protection or remove it again. The longer the battery, the greater the force of the springs on it in the battery compartment; it happens that they push through the negative contact of the Li-Ion battery. Most often this happens when the flashlight is used as an under-barrel flashlight during recoil during a shot. And it’s not very pleasant to push such a battery into the battery compartment of the flashlight by forcefully twisting the lid, scratching and damaging the battery contact with the spring.
But no matter what the battery protection is, it does not 100% guarantee the safety of the battery and flashlight from overheating and even explosion.

Usually, the increased pressure in the battery is released through special holes in the battery valve, but in the sealed space of the flashlight they may not help.

In principle, if you know the approximate effective operating time of a Li-Ion battery based on its capacity in a particular consumer, then you can safely use unprotected batteries. Many people do this. This applies to flashlights with a single battery. If several batteries are used, protection must be required.

It happens that the protection board fails. To restore further use of the battery without it, do the following:

Remove the polymer coating (shell);

On the case you can see the positive conductor going to the protection board, which is simultaneously spot welded to the battery case (minus). In case of critical current and voltage values, the protection board breaks this circuit;

The protection board is removed, freeing from spot welding. Remove the conductor;

Remove the sheath around the negative terminal so that the contact is accessible for connection to the final consumer devices;

Instead of the original shell, you can use ordinary adhesive tape or electrical tape or self-adhesive film of any color, cutting a piece out of it to the size of the battery and carefully covering it with it. With such a film, the battery will become unique, especially if you wrap it in carbon film. :-)

After removing the protection board, the battery will lose 1-3 mm in length. And it will become an ordinary battery without protection.

If, for example, you need to repair the battery in a laptop, upgrade the battery in a screwdriver, or you need a prefabricated BATTERY from Li-Ion batteries, then for this you need to use unprotected batteries.

Pros and cons of lithium-ion batteries

Typically a 18650 battery is li-ion-th battery.

The main advantages of Li-ion batteries are:

High energy density;

Higher voltage (compared to NiCd and NiMH batteries);

Low self-discharge 4–6% per month, 10–20% per year;

No “memory effect”, no need for “training” after purchase - there is no need to fully charge and then completely discharge lithium batteries after purchase;

Wide operating temperature range – from -20 to + 50 °C;

Long service life of about 10 years;

Significant reserve of discharge-charge operating cycles of more than 1000;

Ease of maintenance;

Low specific gravity.

A few disadvantages of Li-ion batteries:

Relatively expensive (every day this minus disappears);

Low resistance to overcharge and complete discharge, which is why smart Li-Ion batteries are equipped with built-in systems automatic shutdown;

Unlimited range of operating temperatures (from -20 to + 50 C), deterioration of performance at high temperatures, reduction in capacity when used in cold weather;

Difficulty charging at low temperatures;

Explosion hazard if the housing is damaged, punctured or otherwise sealed;

Dependence of service life on time, and not on the number of discharge and charge cycles, over time there is a gradual loss of capacity

Storing lithium polymer and lithium ion batteries

Lithium polymer and lithium ion batteries lose capacity when charged, unlike nickel and nickel metal hydride batteries. The higher the battery charge and the temperature during its storage, the shorter its service life. Overcharging, like overdischarging, “burns out” the battery capacity.

The optimal storage conditions for Li-ion batteries are:

• 40-50% charge of battery capacity;
• temperature 0-10 degrees Celsius.

At the same time, low temperature is a more important factor for small losses of capacity during long-term storage. The average shelf life (service) of a lithium battery is on average 36 months. Lithium batteries age even when not used.
(Wikipedia).

To extend the life of your lithium battery and improve its performance, you need to follow simple recommendations:

Avoid completely discharging the battery, recharge it regularly when the charge level drops to 20%;

do not allow the battery to overheat or expose it to direct sunlight;

Do not use the battery in severe frost; insulate it for use in winter;

store the lithium-ion battery with a 50% charge level, at a temperature of 0 C;

protect the battery from shock, damage and strong vibration; when installing it on electric vehicles, use a soft layer

Deciphering markings and inscriptions on batteries

In mass production, three classes of Li-ion batteries are used (based on the cathode material, the second letter in the marking):
1) lithium-cobalt LiCoO2 (the most common, the highest capacity among Li-Ion)
2) lithium-manganese LiMnO2, LiMn2O4, LiNiMnCoO2 (better known as high-current (INR), capable of delivering currents of 5-7C to the load, which are usually inferior in capacity to the former)
3) lithium ferrophosphate LiFePO4 (excellent batteries undervalued by the market, in all respects they undoubtedly outperform the first two types, except for operating voltage and capacity, it is even lower than that of INR)
As they say, all three classes are tailored to perform specific tasks and have their pros and cons.

Since there are no uniform battery labeling standards, all manufacturers label them differently. But ideally it should be something like this:
1) the first letter is the manufacturing technology (I - lithium-ion technology)
2) second letter - type of chemistry, cathode material (C/M/F - cobalt/manganese/iron phosphate chemistry)
3) third letter R - battery (rechargeable)
4) five digits - form factor (the first two digits are diameter, the next two are length, the last digit is the shape of the acca (0 - cylindrical))
- 10440 (everyone’s familiar “little fingers”)
- 14500 (everyone’s familiar “fingers”),
- 16340 (size like a CR123 battery),
- 17335 (not common)
- 18500 (also not very common)
- 18650 (the most common form factor on the market),
- 18700 (unofficially, 18650 battery + protection board, i.e. protected battery),
- 26650 (enlarged, came to the market from the company A123 Systems, which produces lithium ferrophosphate batteries)
- 32650 (absolutely monsters, only for stationary devices, weight almost 150g)
- plus unofficial f/f with protection boards, for example 18670...
5) letters/numbers - specific marking of the container (different for all manufacturers)

An example of marking, but as a rule, it is different for all manufacturers:
- Samsung ICR18650-26F (lithium-ion battery with the usual cobalt chemistry, f/f 18650 with a capacity of 2600mah)
- Samsung INR18650-20R (lithium-ion battery with manganese chemistry, i.e. high-current, f/f 18650 with a capacity of 2000mah)

Own designations:
Panasonic NCR18650PF (NCR is a type of cobalt chemistry, something between the first and second classes, i.e., in simple words, LiNiCoO2 chemistry, without the use of maranz. Although it does not fit a certain class, a kind of symbiosis has turned out. The advantage is high energy density with low thresholds up to 2.5-2.75V). This battery uses LiNiMnCoO2 chemistry, that is, it is already IMR high-current based on manganese, but the manufacturer left the old markings.
Sanyo UR18650FM – the information may not be accurate, but I came across information that Sanyo does not produce batteries for retail sale, and therefore does not bother with labeling. It produces cans for large electronics manufacturers, so the labeling is purely “for itself.” Perhaps, according to the company’s internal designations, UR and F(M) mean type, chemistry and capacity, at least there is no information in the datasheets (only that this is the model marking). And this is a lithium-ion battery with the usual cobalt chemistry, f/f 18650 with a capacity of 2600mah.

Selecting a 18650 battery

Now, after we have studied the main characteristics of batteries, let’s try to figure out how not to make a mistake when buying a battery and what type to choose for specific tasks. Many of us use flashlights and lamps with 18650 batteries, and some also have power banks for these types of batteries.
You should never take the word for the inscriptions on batteries of unknown, little-known or cheap brands.

A clear example of a battery with fantastic capacity

A person who doesn’t understand will immediately fall for it - that’s a fact. Be carefull!

Choosing a 18650 battery. Questions and Answers

If you need simple advice - which 18650 battery is better to buy without delving headlong into the technical component, “so that it just works normally”, we will answer this:

The most affordable in terms of price/quality ratio is the Samsung ICR18650-26F (or H) with a capacity of 2600mAh; most of your devices and flashlights will work on it without problems.

If you increase the cost budget for purchasing a battery by one and a half to two times, you can purchase an almost maximum capacity battery LG18650MJ1 (30% more):

Its analogues are Sanyo (NCR18650GA) and Samsung (INR18650-35E), and Samsung is noticeably cheaper.

If you need a record holder for capacity and quality, then this is definitely what we think this moment Panasonic NCR18650G 3600mAh

Protected and/or unprotected 18650 battery?

Attention! All items on this list are required!

We are talking about electronic protection from overcharge, overdischarge and short circuit. Details with pictures.

Batteries with protection must

• The lantern consists of two or more sequentially installed batteries. "Lantern-baton", like this.
• You are using simple Charger without an overcharge protection circuit and/or from little-known Chinese manufacturers.
• The flashlight is equipped with mechanical protection against polarity reversal of an incorrectly installed battery. For this, a battery with protection with a protruding positive contact is usually used (exceptions are possible, of course).
• The flashlight does not provide information or shutdown protection when the battery is significantly discharged - below 2.6 V, and you don’t want to bother with this (you can simply forget to turn it off).
• The flashlight may fall into the temporary use of forgetful and/or inexperienced people, as well as into the hands of your children and they will torture it until they lose their “pulse”).

Batteries with protection Can

• For flashlights powered by 18650 size batteries, if the protected battery fits freely into it in length (there are no problems with screwing the battery compartment cover) and in diameter (does not rest against the walls during installation).
• Powerful flashlight with parallel connecting two or more batteries. In our opinion, this is a controversial decision.

Unprotected batteries must used in the following cases:

• The battery compartment is too narrow or short in a flashlight designed for one 18650 battery(important!) (impossibility of installing a protected battery that is 2-3mm longer and 0.5mm wider).
• As a rule, a modern flashlight with powerful LEDs (xm-l2 xp-l2) powered by one The battery consumes a lot of current at maximum brightness (3 amps or more). And many protected batteries may simply shut down when turned on due to overcurrent.

Unprotected batteries Can use in the following cases:

1. The flashlight is designed for one battery or it runs on two or more parallel installed batteries.
2. A smart charger is used (smooth reduction of the battery charging current and the function of automatically turning off the battery after charging, selection of charging current, other functions) from trusted brands (liitokala, nitecore)
3. You will never forget to turn off the flashlight after use and/or will not leave it on for long periods of time unattended (unless it has built-in low battery protection).
4. Children do not have access to the Lantern and/or you do not trust others to use it without your presence.
5. You store batteries in a special box and do not throw them anywhere, due to which they can be accidentally shorted by metal objects or random current conductors.

Branded and/or Chinese battery size 18650?

Previously, purchasing a cheap Chinese (from a true Chinese brand) 18650 battery was justified. Several years ago, such batteries were much cheaper than branded ones, and in terms of characteristics they were close to their branded counterparts.
But time goes by. And starting from 13-14, some well-known brands, in order not to be left out, reduced the price so much that purchasing a “folk” battery from China of dubious quality in order to save money became irrelevant.
In 15-16 years, super-capacious batteries - one might say the flagships Panasonic 3600, due to fierce competition from Korean brands, reduced the price almost to the level of what had become popular at that time - Samsung.

Therefore, to the Chinese brand - manufacturer of 18650 batteries (Even if it is already quite popular) we can say: who are you? let's goodbye.

When choosing a battery, do not forget about this:

• There are only four main manufacturers of 18650 batteries from well-known brands: Panasonic, Sanyo, Samsung and LG. There is also Sony with its exotic models, but the ones mentioned above are the most common.
• All other brands (usually manufacturers of various flashlights) wrap the same Panasonic, Sanyo, Samsung and LG in thermal covers with the names and logos of their brand, well, maybe even providing these batteries with a protection board and/or modified contact pads.
• As a rule, after this they receive a noticeable increase in price, although they are no better in terms of characteristics.
• It’s true that it’s worth noting that sometimes such modified batteries can be better than their donors, since they should work without problems with flashlights from the manufacturer of the same brand (with others there may be problems due to size, contacts and current overloads).
• For some “special” flashlights, you need to purchase batteries that are recommended by the manufacturer or specified in the description/instructions for the flashlight.

Selection of capacity18650 battery

At the time of writing, large capacity according to real measurements has only one type of battery: Panasonic NCR18650G 3600mAh. What is more (there are fantastic inscriptions 4000, 5200, 9800 and even 12000!), and sometimes even quite real ones from little-known/unknown Chinese brands in fact black marketing and blatant lies our Chinese “friends” of underground production. Usually, bright labels and super inscriptions are used to hide the “pig in a poke.” On the fonarevka.ru forum, read the article Horrors of our town. In the best case, you will get working junk with a capacity of 1800-2000 mAh and a lifespan of six months to a year.

But even a branded battery with a really high capacity is not a panacea. It happens. that the operating time of the flashlight does not always increase noticeably with the installation of a high-capacity battery, and there are reasons for this. In everyday living conditions, a Samsung battery with a capacity of 2600 mAh can cope with the tasks at hand. It's an affordable workhorse for all conditions. If you are still leaning towards batteries of higher capacity (2800, 3200, 3400 and 3600mAh), adhere to the following rules:

• Purchase batteries only from well-known brands and manufacturers.
• Popular Panasonic Li-ion batteries are capable of delivering their full capacity when discharged to 2.5 v. The truth is worth noting. that not all flashlights and powerbanks are capable of working with such low voltage. All “baton flashlights” (with 2-3 18650 batteries installed in series) and flashlights of high-quality Chinese and other brands (Convoy, etc.) running on a single 18650 battery can cope with this.
• If you use high-capacity batteries from LG or Samsung, then they need to be recharged to their operating non-standard voltage of 4.35V (the standard voltage is 4.2V), most likely using an expensive “smart” charger. An example of such a battery is the LG ICR18650E1 with a capacity of 3200mAh.
• The LG INR18650-MJ1 battery with an announced capacity of 3500mAh is physically capable of working for a long time and quietly delivering high current to the load. Moreover, its operation is carried out in the range of standard voltages of 4.2 - 3.0V Li-ion batteries. Analogues of this battery are: Sanyo (NCR18650GA); Samsung (INR18650-35E).

From all of the above, we can assume that if any of these operating conditions for more capacious and expensive batteries are violated or not met, you will most likely get the same effect from their use and operating time as from the cheaper Samsung 2600. Be that as it may from the most capacious and most expensive ones, in an ideal situation and luck - it will shine only 10-30 percent longer than usual!

Approximate price in Chinese online stores at the time of writing, it is $2-2.5 for one can of Samsung 2600mAh and $4-6 for a can of the most capacious Panasonic 3400mAh - 3600mAh. Good, high-quality protection will add another 1-3 dollars. You will have to pay a few more dollars for a beautiful wrapper from the lantern manufacturer.

The meaning of the inscriptions in English in the description of the battery 18650

• The battery capacity is designated " mAh". mAh – milli-Ampere-hour translated into Russian, as you may have guessed.
• Batteries with protection are marked " With protective PCB", "Protected", "Protection Circuit" and so on..
• Nothing is indicated about those who are not protected, or in rare cases they are indicated " Unprotected".
• Numbers indicating voltage 3.6V and 3.7V essentially mean absolutely the same thing. Represents the average voltage for a battery that needs to be charged to 4.2V. As a rule, the manufacturer decides for himself whether to indicate one or the other value.
• If the voltage is indicated on the label or in the description 3.8V then this means that the battery should be charged to non-standard 4.3 or 4.35 Volt.
• Voltage value 3.2 V usually denoted Lithium iron phosphate battery . If you haven’t heard of this and don’t know what its purpose is, just forget about it, most likely you won’t need it.

Cases of counterfeit 18650 batteries

There have been almost no cases of counterfeit batteries from the main brands: Samsung, Sanyo, LG and Panasonic. But with other brands you need to be more careful - the situation may be different.

Attention! There have been cases of unscrupulous sellers selling old, worn-out batteries from the dismantling of large batteries from electric cars or electric bicycles.

You can determine the manufacturing date using the manufacturer's code on 18650 batteries using this link:
https://batterybro.com/18650-date

Suitable for:
Samsung
Sony
Panasonic
Sanyo
LG

Signs of such batteries:

• Remnants of removed contact welding on the poles (scratch spots on the ends)
• Remains of sealant (glue) on the battery case

Applications

Table of characteristics for famous brands

			Marking	Charge voltage	final voltage	discharge current A continuous (maximum)
						6.4-2C(10-3C)
						6.4-2C(10-3C)

	Manufacturer		Marking

Materials used in the article

P.S. I’ll add on my own behalf as a person who has been using this type of battery for a long time - Take Liitokala, Sanyo, LG, Samsung or Panasonic!

DO NOT TAKE UltraFire or worse, especially with a capacity higher than 3000mAh

I’ll say right away that Li-ion (lithium-ion, lithium) batteries size 18650 at 3.7v, like many other things, I buy on AliExpress. Links to them are at the bottom of the article.

Why there? Because on AliExpress has a very large selection and you can buy them at a very affordable price..

But precisely because 18650 batteries are very popular, the Chinese are very fond of counterfeiting them, so it’s not worth rushing for beautiful numbers with an unrealistically large capacity or a low price.

I will talk very briefly about the batteries themselves, give some advice - which batteries are better not to buy, how to use them, and give links to really good 18650 batteries, and which ones are better is up to you to decide, because. and their characteristics and purpose differ, although the average operating voltage is the same for all - 3.7v.

Usually, 18650 battery size is: diameter - 18-18.3 mm, height - 65 mm (for batteries without protection). Protected batteries have a diameter of about 18.5 mm and a height of up to 70 mm.

A protected battery, unlike an unprotected one, has a board built into it (charge/discharge controller), and it externally has a positive contact like a small (about 1 mm) protruding pin.

This controller protects the battery from overcharging above 4.2v and from discharging below 2.75-3.0V (different batteries have different lower values, you should look at its description (datasheet), because beyond these values ​​the battery will quickly fail.

Which one is better to use? It depends on what you charge it with and where you use it..

As a rule, normal chargers (designed specifically for charging lithium-ion batteries, for example the 18650 type) have a charge controller and do not overcharge these batteries, so any type can be used in them.

PowerBanks have a full charge and discharge controller, so they use batteries without protection, and in some cases protected batteries will not even fit into the PowerBank due to the protruding contact.

But if you use a battery, for example, in a simple Chinese lantern, a children's car or an electronic cigarette, where there is no built-in discharge controller, then you must use a battery with built-in protection, otherwise it will not last long.

By the way, about electronic cigarettes, mechanical mods and so on. – it’s better to use them high current 18650 lithium batteries, designed to deliver high currents - up to 40-60 A(short term). Conventional batteries designed for loads of 2-3C (up to 4-5A) will also “die” quickly.

If you use a battery with a step-up voltage converter, then pay attention - at what minimum input voltage does this converter start working? If it’s from 3 volts, then everything is fine, you can use any type, but if, for example, from 2 volts, then the battery without built-in protection will be “sucked out” completely, which “is not good.”

Regarding the capacity of 18650 batteries: at the time of writing (beginning of 2017), the maximum capacity that I encountered was a maximum of 3400 mAh, and only from well-known manufacturers such as Sanyo, Panasonic, most others, for example LG, Sony, Samsung, etc. - about 3000 mAh, and the price for them is also not the lowest.

Personally, today I prefer already time-tested 2600 mAh batteries from Sanyo and Samsung, which can already be purchased at a very affordable price.

But, On AliExpress you can buy a lot of cheap fakes like Ultrafire, on the cases of which the capacity may be indicated as 3000, 5400, or even 9000 mAh, etc., but the real capacity of which will be 5 or even 10 times lower!

Also, if you have an 18650 battery and have nothing to check its actual capacity, then just weigh it! Batteries with a capacity of 2000 mAh or more must weigh at least 40 grams! And, as a rule, the higher the actual capacity, the more it will weigh.

Although some “leftist” manufacturers have already learned to “bypass” this point. They just add something inside for weight, like regular sand.

That's why, Don’t chase a low price and big numbers on the case, you shouldn’t save on this!

The most reliable thing is to use verified links, but always, without fail, anyway carefully read reviews for a specific battery and then you won’t get into trouble.

We encounter electricity every day. It so happens that everything around us, from light bulbs to cars, uses electrical energy. Household appliances around us are connected to a 220 V network. But besides them, there are also mobile devices that we take with us to work or on a trip. These devices also require electricity.

Autonomous power supply for devices or power tools can be provided by a battery. The very name of the device speaks about its purpose to accumulate (accumulate) electricity. The larger the battery capacity, the longer the consumer can work. Production technologies are improving every day. 18650 batteries become more powerful, hold operating voltage longer and reduce the time required to charge.

We have compiled a list best batteries 18650, based on expert assessments and reviews from real customers. Our recommendations will help you make a choice that suits your needs and desires. There are many competitors in the global technology market, but we have selected the best manufacturers and recommend paying special attention to them:

1. ROBITON
2. Bright BEAM
3. Rexant
4. Samsung
5. Panasonic

For lanterns For screwdrivers For power banks Capacity: up to 2000 mAh Capacity: 2000-3000mAh Capacity: over 3000 mAh Solderable With protection

*Prices are correct at the time of publication and are subject to change without notice.

18650 batteries: For flashlights

For lanterns / Capacity: 2000-3000mAh / Capacity: up to 2000 mAh/ With protection

Main advantages

• High-capacity lithium-ion battery weighing less than 42 grams with built-in surge protection while charging the device
• The marking on the battery “With Re/Discharging Protection Circuit” indicates that the protection system blocks charging current exceeding 4.25 V or less than 2.75 V to preserve battery functionality
• Designed for installation in devices that require large battery capacity, such as high-power LED lights or rechargeable batteries in laptops
• The battery has a high efficiency (about 90%), which indicates its high energy intensity and good performance characteristics
• Compact dimensions allow the battery to be used for work in small devices and devices of portable or stationary type

For lanterns / Capacity: 2000-3000mAh/ With protection

Main advantages

• Rugged battery based on the powerful original Samsung battery for use in high power consumption devices
• The lithium-ion battery does not have a “memory effect” and does not lose capacity if the charging mode is violated. Regardless of these cycles, the current is supplied completely during operation
• The battery is equipped with protection against current fluctuations during overcharging or overdischarging, which prevents its failure and extends its effective service life
• Manufactured to strict standards so the battery's exact diameter is suitable for use in e-cigarettes whose design limits the battery's allowable size
• Thanks to the Li-ion electrochemical system, batteries of this type are not afraid of frequent recharging. Battery capacity of 2200 mAh (3.7 V) is enough to power most compact devices

Show all products in the category "For flashlights"

18650 batteries: For screwdrivers

For lanterns / For screwdrivers / Capacity: up to 2000 mAh/ With protection

Main advantages

• Battery with a rated power of 1100 mAh and an operating voltage of 3.2 V is ideal for LED flashlights
• Innovative Nanophosphate® technology ensures stable operation of the battery regardless of environmental changes. Does not require cooling in case of overheating and heating in extremely low temperature conditions
• The ability to operate in a wide range from - 20 to + 60 and store from - 20 to + 45 degrees Celsius significantly expands the scope of application of the battery
• Allowed fast charging for 12 minutes, which is carried out by a high current of 4 A
• A high degree of battery operating safety is ensured due to the thermal and chemical stability of the device

Show all products in the category "For screwdrivers"

18650 batteries: For power banks

For power banks/ For lanterns / Capacity: 2000-3000mAh/ With protection

Main advantages

• Battery with lithium-ion electrochemical system for installation in flashlights or other high-power devices
• Built-in protection against voltage surges during charging and discharging cycles protects the battery from failure and extends its service life
• Does not have a negative “memory effect”. This eliminates loss of capacity in case of violation of the correct charging cycle and incomplete discharge during operation
• Sufficiently large capacity of 2800 mAh (3.7 V) ensures long and efficient service life of devices
• The compact dimensions of the battery allow it to be used in small-sized mobile devices and facilitate storage and transportation

Show all products in the category “For power banks”

18650 batteries: Capacity: 2000-3000 mAh

For lanterns / Capacity: 2000-3000mAh/ With protection

Main advantages

• Protected 2600mAh lithium-ion battery based on Sanyo 3.6V
• Designed for use in professional YLP series flashlights with a single 18650 battery that do not include a battery or charger
• To improve ease of use, the battery is equipped with a charging board, which is connected via a micro-USB connector.
• Built-in indicators allow you to visually monitor battery charging. This can be useful in low or no light conditions
• The compact dimensions of the power supply (diameter 18.6 mm, length 70 mm) facilitate storage and transportation. The battery is packed in a bright gift-type blister

Show all products in the category "Capacity: 2000-3000 mAh"

18650 batteries: Capacity: over 3000 mAh

For power banks / For screwdrivers / Capacity: over 3000 mAh/ Solderable

Main advantages

• Unprotected high capacity lithium battery capable of delivering high discharge current in a relatively small size
• Has a fairly long service life. The battery confidently withstands up to 500 charge and discharge cycles before the energy capacity drops to 80% of the nominal value
• For use, it requires the installation of a special board (PCM), which protects the battery from overcharging or overdischarging and protects against premature failure
• When installed in devices that have a built-in battery condition monitoring function (for example, all Armytek line flashlights), a protective board (PCM) is not installed
• The battery is demanding on charging and discharging currents. They should not exceed 4.2 - 4.35 V (charging) and 2.5 - 2.7 V (discharging). Failure to comply with these conditions will result in battery failure.

For power banks / For screwdrivers / Capacity: over 3000 mAh/ Solderable

Main advantages

• Industrial (unprotected) 18650 lithium-ion battery with a capacity of 3400 mAh and a nominal voltage of 3.6 V
• The batteries have a maximum real capacity in 18650 format and the ability to support high load current without reducing voltage
• Most top brands of laptops are equipped with batteries of this model. Thanks to the presence of these batteries (Battery Pack), the devices are subsequently able to operate in autonomous mode for quite a long time
• The special chemical composition of the battery prevents fire even if the cell is damaged
• Has high efficiency and a long service life of up to 500 discharge and charge cycles, with a loss of capacity of only up to 80% of the nominal

For lanterns / Capacity: over 3000 mAh/ With protection / For screwdrivers

Main advantages

• Protected Li-ion battery size 18650 with a large capacity of 3400 mAh and a maximum discharge current of 6.8 A. Based on the original Panasonic 3400 mAh battery
• Does not have a negative “memory effect”. The discharge and charge capacity does not depend on the residual capacity. Does not require strict adherence to charging cycles
• Equipped with a protection board that avoids current fluctuations when restoring capacity. This extends battery life and prevents battery failure
• Ideal for Battery Packs for laptops or power tools
• Battery with high efficiency and long service life up to 500 recovery cycles. This confirms its high energy intensity and excellent performance characteristics.

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.

Contents

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. Despite the fact that they do not have a large capacity and do not differ 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.

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.

How the marking is deciphered

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

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, 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.

Where are 18650 batteries used?

The scope of batteries and the frequency of their use is much wider than many people think. Due to the fact that they are closed with special protection, they are not always visible.

Installed in the following devices:

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

They are used wherever ordinary AA batteries are unable to cope with the task. Li ion 18650 batteries have a higher 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 batteries do not have such a noticeable external difference between the positive and negative terminals, but it’s quite easy to understand:

• On the “plus” side there are 3-4 small holes.
• The “plus” side sticks out a little.”
• “The minus is completely flat.

General characteristics of 18650

Capacity (mAh)	Output voltage (V)	Maximum current (A)	Protection board
1100	3.3		+/-
1300	3.6	18	+/-
1620	3,6-3,7	20	+/-
2000	3,6-3,7	20-30	+/-
2100	3,6-3,7	20-30	+/-
2200	3,6-3,7	20-30	+/-
2400	3,6-3,7	20-30	+/-
2500	3,6-3,7	20-35	+/-
2600	3,6-3,7	20-35	+/-
2800	3,6-3,7	20-35	+/-
3000	3,6-3,7	20-35	+/-
3100	3,6-3,7	20-35	+/-
3200	3,6-3,7	20-35	+/-
3350	3,6-3,7	20-35	+/-
3400	3,6-3,7	20-35	+/-
3500	3,6-3,7	20-35	+/-
3600	3,6-3,7	20-35	+/-

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 specifications 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. If we talk in simple language, then the current strength affects the tendency of the battery to overheat.

Voltage battery 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 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.

Serial connection 18650 batteries

How to check battery capacity

There are several effective ways 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.

A device that measures real capacitance

To implement the third method, you will need such parts as a battery, a watch, an ammeter with a flashlight. You need to insert the battery into the flashlight, turn it on 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 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.

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.

It is difficult to find an area where there are no devices running on electrical energy. Mobile sources include rechargeable batteries and disposable batteries that power the consumer by converting chemical energy into electrical energy. Lithium-ion batteries are electron pairs with active components containing lithium salts. The shape of the battery resembles a disposable AA battery, but is slightly larger, has hundreds of charging cycles, and belongs to Li-ion 18650 batteries.

Production of lithium-ion batteries is based on company sites Sanyo, Sony, Panasonic, LG Chem, Samsung SDI, Skme, Moli, BAK, Lishen, ATL, HYB. Other companies buy elements, repackage them, passing them off as their own products. They also write false information about the product on the shrink film. There are currently no 18650 Li-ion batteries with a capacity higher than 3600 mAh.

The main difference between rechargeable batteries and batteries is the possibility of repeated recharging. All batteries are designed for a voltage of 1.5 V, the product has a li-ion output of 3.7 V. Form factor 18650 means a lithium battery 65 mm long, 18 mm in diameter.

18650 lithium battery operating mode characteristics:

• The maximum voltage is 4.2 V, and even minor overcharging significantly reduces the service life.
• The minimum voltage is 2.75 V. When reaching 2.5 V, special conditions for capacity restoration are required. When the voltage at the terminals is 2.0 V, the charge is not restored.
• The minimum operating temperature is -20 0 C. Charging at sub-zero temperatures is not possible.
• Maximum temperature +60 0 C. At higher temperatures, an explosion or fire can be expected.
• Capacity is measured in Amps/Hours. A fully charged 1Ah battery can supply 1A of current for an hour, 2A for 30 minutes, or 15A for 4 minutes.

Charge controller for li-ion battery 18650

Major manufacturers produce standard 18650 lithium batteries without a protective board. This controller, made in the form of an electronic circuit, is installed on top of the case, lengthening it somewhat. The board is located in front of the negative terminal and protects the battery from short circuits, overcharging, and overdischarging. Defense is being assembled in China. There are devices good quality, there is an outright scam - unreliable information, capacity 9,000A/h. After installing the protection, the case is placed in shrink film with inscriptions. Due to the additional design, the case becomes longer and thicker, and may not fit into the intended slot. Its standard size can be 18700, and can be increased due to additional actions. If the 18650 battery is used to create a 12V battery that has a common charge controller, breakers on the individual Li-ion cells are not needed.

The purpose of protection is to ensure the operation of the energy source in given parameters. When charging with a simple charger, the protection will not allow overcharging and will turn off the power in time if the 18650 lithium battery runs down to a voltage of 2.7 V.

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 – Panasonic specific markings. 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.

How to test a 18650 lithium battery

If, when buying an expensive device, you doubt the veracity of the information on the case, there are ways to check. In addition to special meters, you can use improvised means.

• You have a charger, you can time the time of full charging with a certain current strength. The product of time and current will reveal the approximate capacity of the li-ion battery.
• A smart charger will help you. It will show both voltage and capacity, but the device is expensive.
• Connect the flashlight, measure the current, and wait for the light to go out. The product of time and current gives the current capacity in A/h.

You can determine the power of a battery by weight: a 18650 lithium battery with a capacity of 2000 mAh should weigh 40 g. The higher the capacity, the greater the weight. But the defectors have learned to add sand to the body to make it heavier.

Charger for 18650 lithium batteries

Lithium batteries are demanding on terminal voltage parameters. The maximum voltage is 4.2 V, the minimum is 2.7 V. Therefore, the charger works as a voltage stabilizer, creating 5 V at the output.

The determining indicators are the charging current and the number of elements in the battery, which you set yourself. Each element (jar) must receive a full charge. Power is distributed using a balancer circuit for 18650 lithium batteries. The balancer can be built-in or manually controlled. Good memory is expensive. Anyone who understands the electrical diagrams and knows how to solder.

The proposed do-it-yourself charger circuit for 18650 lithium batteries is simple and will turn off the consumer after charging on its own. The cost of components is about 4 dollars, not a shortage. The device is reliable, will not overheat and will not catch fire.

Charger circuit for lithium 18650 batteries

In a homemade charger, the current in the circuit is regulated by resistor R4. The resistance is selected so that the initial current depends on the capacity of the 18650 lithium battery. What current should be used to charge a li-ion battery if its capacity is 2,000 mAh? 0.5 - 1.0 C will be 1-2 amperes. This is the charging current.

What current to charge a li-ion battery 18650

There is a procedure for restoring the functionality of a 18650 lithium battery after the voltage drops to working voltage. We restore capacity measured in amp hours. Therefore, first we connect the Li-ion battery form factor 18650 to the charger, then we set the charging current with our own hands. The voltage changes over time, the initial value is 0.5 V. As a stabilizer, the charger is designed for 5 V. To maintain performance, parameters of 40-80% of the capacity are considered favorable.

The charging scheme for a li-ion 18650 battery involves 2 stages. First, you need to raise the voltage at the poles to 4.2 V, then stabilize the capacitance by gradually reducing the current. The charge is considered complete if the current drops to 5-7 mA when the power is turned off. The entire charging cycle should not exceed 3 hours.

The simplest single-slot Chinese charger for li-ion 18650 batteries is designed for a charging current of 1 A. But you will have to monitor the process yourself, switch it yourself. Universal chargers are expensive, but they have a display and carry out the process independently.

How to properly charge a Li-ion 18650 battery in a laptop? Connecting a set of energy sources in the gadget via Pover Bank. The battery can be charged from the mains, but it is important to turn off the power as soon as the unit has reached capacity.

Restoring li-ion battery 18650

If the battery refuses to work, it may manifest itself as follows:

• The energy source is quickly discharged.
• The battery is dead and won't charge at all.

Any source can quickly discharge if the capacity is lost. This is precisely why overcharge and deep discharge are dangerous, from which protection is provided. But there is no escape from natural aging, when storage in a warehouse annually reduces the capacity of the cans. There are no methods of regeneration, only replacement.

What to do if the battery does not charge after a deep discharge? How to restore li-ion 18650? After the controller disconnects the battery, it still has a reserve of energy capable of delivering 2.8-2.4 V voltage at the poles. But the charger does not recognize a charge up to 3.0V; anything lower is zero. Is it possible to wake up the battery and start the chemical reaction again? What needs to be done to increase the charge of li-ion 18650 to 3.1 -3.3V? You need to use a way to “push” the battery, give it the necessary charge.

Without going into calculations, use the proposed circuit, mounting it with a 62 Ohm resistor (0.5 W). A 5V power supply is used here.

If the resistor heats up, the lithium battery is zero, which means there is a short circuit or the protection module is faulty.

How to restore a 18650 lithium battery using a universal charger? Set the charge current to 10 mA, and perform precharging as written in the instructions for the device. After raising the voltage to 3.1 V, charge in 2 stages according to the SONY scheme.

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 3000-3200 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