Among Li-Ion batteries, the 18650 battery is especially popular. Its scope of application is very wide: such elements can be found in battery packs for laptops, screwdrivers, and in devices such as mechanical mods designed to power electronic cigarettes or household flashlights. They can be found in portable handsets of landline telephones. Also, recently, converting a screwdriver from nickel-cadmium to lithium batteries of this particular type has been gaining popularity, due to the fact that they work much longer than elements of the previous generation.
When an 18650 battery is inserted into a particular device, how to charge it correctly and for how long are questions that any responsible owner of a household electrical appliance with such batteries will ask.
18650 battery
Many users sometimes confuse this battery with a regular 1.5 volt battery. But this is wrong, his tension is much greater. Yes, and the dimensions are different.
18650 battery what is it?
This is a rechargeable battery with the ability to recharge. Some types have a built-in port and the ability to receive charge from a USB connector. This solution is very convenient.
Thus, from the above definition it becomes clear what kind of tr18650 batteries are.
Statistics on used laptop batteries
Hi all. Maybe someone needs statistics on Li-Ion used batteries from laptops. I bought 50 pieces of non-working laptop batteries for 100 rubles each, after which I gutted them and assembled batteries for my solar power plant.
I tested them with a tester from a well-known Chinese company. I completed the cells, collected 42 Ah for each cell. Did 7s18+p. I rejected all elements below 1500mAh and with a resistance much higher than the nominal value according to the datasheet. Based on this bar: the percentage of defects turned out to be almost 50%. 154 out of 300 elements were used.
Welded using portable spot welding. Total cost of 5,000 rubles. I received a 24v 42 Ah battery.
18650 battery specifications
Below we present to your attention the main parameters of this battery.
Voltage
After analyzing a number of online stores, a conclusion was made. Most 18650 batteries are 3.6 volts. But there are options with 3.7 V. At the moment of full charging, the voltage increases to 4.2-4.3 V.
How many amps are in a 18650 battery?
The current strength depends on the specific battery model. The number of amperes in a 18650 battery, according to some sources, is from 0.5 A and above.
Battery capacity 18650
The maximum capacity of 18650 batteries reaches 3600 mAh. The minimum is 1500 mAh. Most often, batteries with increased capacity are used for quadcopters and other energy-consuming devices.
How to determine the capacity of a 18650 battery?
This parameter is determined using a special multimeter tester. You can also see it on the label.
The internal resistance of the 18650 Samsung 25R battery, at room temperature conditions, is 0.022-0.025 ohms.
18650 lithium battery dimensions
The dimensions of this power source depend on the manufacturer and the availability of protection. If there are no protective elements, the size will be smaller.
Battery sizes from Robitin 3600 mAh:
- Length: 64.93 mm
- Diameter 18.20 mm
Thus, the 18650 size is significantly larger than a regular AA battery.
Color
The markets can have both the most common colors and exclusive ones. For example, you can find brown 18650 chocolate batteries.
Main advantages
- Easy to maintain.
- Low specific gravity.
- Low self-discharge level.
- High energy density.
- The 18650 battery has no memory effect.
- Service life is from 7-10 years.
Recommendations from experts
Experts recommend taking a responsible approach to the process of charging and discharging the battery. Its durability depends on this. It is not worth discharging the battery completely and charging it to 100%. It is better to limit the charging process to 90%. However, periodically (every three months) you can completely discharge and fully charge the battery. This is necessary to calibrate the controller.
The battery can be stored for quite a long time. To do this, you need to charge it 50%. She can remain in this state for about a month. At the same time, the room should not be too hot or too cold. Ideal conditions are considered to be keeping the temperature at 15 ºС.
By looking at how to charge a 18650 battery, you can properly maintain and operate the battery. In this case, its service life will be much longer.
Battery type 18650
There are three main options:
- Lithium iron phosphate, also called ferrophosphate, also LFP, LiFePO4, IFR. (Lithium Iron Phosphate).
- Lithium Manganese Oxide. They are also IMR, LiMn2O4, NMC, LiNiMnCoO2, LiMnO2, INR. High current.
- Lithium Cobalt Oxide. These include LiCoO2, NCR, ICR. They have high capacity.
First
Considered the safest. Their operation is quite stable and with high efficiency. They have an iron phosphate cathode. This means that it has zero toxicity. The battery is tolerant to high temperatures.
The 18650 battery does not have a charge controller. If the case is severely deformed, these batteries may explode or ignite. This happens in very rare cases. 18650 is weakly sensitive to incorrect operation. For example, reducing resistance.
Second
Quite in demand by consumers. They manifest themselves as stably operating batteries. Many manufacturers write that option No. 2 18650 is safe. But in reality this is not entirely true. They don't have a charge controller.
The main advantage of such batteries is that they work with low resistance for a long time. Compared to the cobalt type, manganese ones last longer. Their capacity and current are balanced. The maximum charging current is 4.2 volts. Do not neglect the current strength, this may deteriorate the battery and cause an explosion. The current level affects the charging time.
Can withstand a discharge of 2.5 volts. The anode is made of graphite. With low resistance and high current, gas may escape. These batteries are of sufficient quality and are recommended for widespread use.
Third
It has the largest capacity, unlike those listed above. Their system can be unpredictable. Such 18650 batteries cannot be charged with fast charging. It is prohibited to use in devices that place a large load on the battery.
If you know that certain equipment quickly drains the li 18650 battery, do not put them there. Otherwise, ignition of the electrolyte cannot be avoided. The main device in which they are used at the moment is electronic cigarettes. Charging voltage 4.2 V. If you increase the voltage, overcharging may occur, and this is undesirable. Do not use powerful charges - this may deteriorate the chemical composition of the battery.
Thus, it was only described what types of 18650 batteries there are.
Decoding battery labels
There are no standards in labeling, there are no good 18650 batteries. Each manufacturer puts its own marks. But there is still some decoding.
1) The very first sign means by what technology this battery was developed (I - lithium-ion technology).
2) The next sign is the chemical composition of what the battery is made of (F/C/M/ - iron phosphate chemistry, cobalt, manganese).
3) R - means rechargeable 18650 battery.
The number 18650 means the following form factor:
- The first 2 digits are diameter.
- The next pair tells how long this element is.
- The latest one notifies that the battery is cylindrical in shape.
Letters/numbers are a special marking of energy density (capacity). Each manufacturer writes it differently.
Options:
- Samsung INR18650-20R (lithium-ion battery with manganese chemistry, high current, 2000mah).
- Samsung ICR18650-26F (lithium-ion battery with cobalt chemistry, 2600mah).
- Panasonic NCR18650PF (NCR is a type of cobalt chemistry, this is the middle ground between the first and second options, or LiNiCoO2 chemistry, without the use of manganese. It does not fit existing types, it turned out to be a kind of mixture. The positive side is increased energy density with low thresholds up to 2.5-2 .75V). LiNiMnCoO2 chemistry is used. That is, this high-current IMR is made on the basis of manganese, but the creator left the same mark.
- Sanyo UR18650FM – Sony usually stamps brands in its own way. This is a lithium ion battery with a capacity of 2600 mAh.
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.
- 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.
- IMR – lithium manganese cathode. It has the ability to produce high currents and can withstand discharge up to 2.5 a/h.
- INR – nickelate cathode. Provides high currents, withstands discharge up to 2.5 V.
- 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.
Which 18650 battery is better and how to choose it?
Based on safety considerations, the best 18650 batteries are lithium iron phosphate. They are low toxic and less likely to explode. When a battery is needed for a flashlight, any kind will do. But remember, if the charger is not reliable, it is better not to charge a battery that does not have protection.
When choosing an 18650 battery, decide for what purpose it is needed. If you are going to use it in gadgets, for example, in a laptop, bicycle, storage battery, then it is better to give preference to the unprotected option. Such types are produced by Panasonic, Samsung, LG, Sony. They usually have flat side edges.
Protected batteries have a special micro board installed inside the case. This tool prevents the battery from overcharging. In addition, it protects against short circuits. This type of flashlight should be used if there is a series connection of two such batteries.
High-capacity 18650 batteries Panasonic 3600 (NCR18650G) and Sanyo 3500 mAh are good for laptops. The cheapest and most popular are Panasonic 3100 mAh.
When choosing, be guided by the types of batteries indicated in the section above!
What else is worth paying attention to?
- Rated current.
- What kind of heating can there be, how does it heat up?
- Voltage.
- Energy capacity.
What to do if 18650 does not charge
A situation where the battery does not charge occurs after lithium-ion cells have been stored for a long time or have been overcooled.
The power controller disconnects the battery banks from the terminals when the voltage drops below the permissible level of 2.4 V - the measured voltage at the terminals of a non-working battery is 0 V.
You can increase the voltage on the battery and limit the maximum current by connecting a resistor to the circuit by assembling a circuit from a telephone power supply with a current above 0.1 A, a 300-1000 Ohm resistor with a power of 0.5-1 W and a voltmeter. We plug the charger into the network for one or two minutes - we control the voltage, after it reaches 3 V, we turn off the circuit and put the battery on charge.
Attention! We check the 18650 during the entire charging process; when it gets hot, we immediately turn off the charging - an element that gets very hot during charging cannot be restored.
18650 battery device
Inside and outside, this battery has the following structure:
- Fuse.
- Gasket.
- Positive conclusion.
- Current anode puller.
- Pressure relief valve.
- The insulation is usually made of cellophane.
- Positive electrode.
- Separator.
- Isolation.
- Negative conclusion.
- Frame.
- Negative electrode.
Typically, an 18650 battery consists of an anode made of copper and a cathode made of aluminum. The built-in electrodes are separated from each other by a special separator. This unit has a porous structure. It is impregnated with electrolyte. The electrodes are carefully packaged in a dense cylindrical housing. Positively charged lithium ions located in the separator penetrate into the graphite crystal lattice. This element is connected to the negative pole of the battery. An electric current potential is formed at the positive.
Peculiarities
When considering how to charge an 18650 battery for a flashlight, electronic cigarette and other devices, it is necessary to describe the principle of its operation. The presented standard size is available in the lithium-ion battery category. It has small dimensions. The height is only 65 mm and the diameter is 18 mm.
Inside the device there are metal electrodes between which lithium ions circulate. This allows the generation of electric current to power equipment. When the charge is low or high, more ions are formed on one of the electrodes. They grow on the material, changing its volume and characteristics.
In order for the battery to work long and fully, it is necessary to prevent the appearance of a deep or too high charge. Otherwise, the device will quickly fail. Depending on the battery ratings, special types of chargers are used.
How to charge a 18650 battery?
The 18650 Li-ion battery should be recharged frequently. Otherwise, he may lose his former agility.
- Charging occurs at a voltage of 0.05 V, and should be completed when the voltage reaches a level of 4.2 volts. This way the battery will be intact.
- Charging can be carried out at a current of 0.5-1 Ampere. Therefore, it is now clear what current to charge a li ion battery 18650 with. The first value is the most balanced. The second will make the charging process faster. But you should not increase the current unless necessary.
- 18650 batteries should be recharged in no more than 3 hours. Otherwise the chemistry may suffer. It's good if there is built-in protection. In this case, the battery will turn itself off.
- You don't want the battery to drain too much. It will be difficult to return to the previous characteristics. It needs to be recharged from time to time.
- For the first time, 5 charge cycles and 5 discharge cycles should be performed.
How to charge a 18650 battery without a charger?
Without a charger, you can fill the battery with energy only through the USB port. To do this, your battery must have a special connector. Details in the video.
Charger for 18650 batteries
You can charge this battery yourself using a standard charger. Typically, a device with 1 socket is capable of charging with a current of 1 Ampere. Such a device will be convenient for those people who charge once every 12 months.
Connect the 18650 battery charging module strictly, observing the polarity.
Those chargers that have 2 slots for batteries with 4.2 V. If you increase the voltage the battery will die. Fortunately, there is an indicator that monitors the process.
In retail trade you may find mixed types of chargers. They are designed for both 18650 batteries and regular NiCd batteries.
Devices that have a high cost are more richly equipped. They have relays and all possible control indicators. Therefore, charging for 18650 lithium-ion batteries will be more reliable.
What to do if 18650 does not charge?
- Check the production date, it may have already expired.
- Think about how many charge and discharge cycles you have already done. If it is more than indicated in the battery characteristics, then it has already served its purpose.
- Check if the charger is working properly. The wire may have been crushed.
- Pay attention to the contacts. There is a possibility that the contact between the battery and the tin plate may be damaged. The cause may be plaque, rust or oxidation.
- Check if there is electricity in the house.
These five points will help you understand why the 18650 battery does not charge.
How to charge a 18650 battery using a phone charger?
The video below provides instructions on how to do this correctly. Here's what you'll need:
- Mobile charger TR 4056.
- Battery
- Soldering iron.
- Wires.
- USB cable with suitable connector.
- Phone charger.
After assembly, all that remains is to connect it to the phone's charger using a USB cable.
But charging 18650 from a solar battery is possible if you create a special device that delivers the required current. But in reality, you will have to try to bring the design to life. There is no finished development yet.
Watch the video on how to build a cool battery with solar panels.
Advice! It is best to buy a charger for 18650 li ion CV or CC batteries.
How to make a charger for 18650 batteries?
Charging for li ion batteries can be done on the LM 317 chip. Below is a diagram and what it looks like assembled.
The video provides an example of creating a charger for this battery.
Which device should you use?
Different models of chargers differ in technical characteristics, set of functions and some other parameters:
Liitokala Lii-500 is a universal charger that automatically selects currents for charging batteries.
- Simple. Such devices supply a current of 1 A. They have a single socket for installing an 18650 battery.
- Improved. The device is equipped with 2 battery slots. The maximum voltage level is 4.2 V. This charger is more expensive. Additional functions include charge indication. The device automatically limits the procedure time, preventing overcharging.
- Universal. Used to charge power supplies of the 18650 and 26650 types. Models of this type are used to restore the functionality of lithium-ion and nickel-cadmium cells. The best devices are equipped with a safety system that eliminates the need for regular voltage and current measurements.
- Homemade. If a ready-made device cannot be found, the charger can be assembled at home. The components are connected according to the diagrams.
The quality of the memory largely depends on the cost. Cheap devices do not have components that allow you to abandon constant monitoring. Using an incorrectly assembled homemade device may result in battery failure or personal injury.
How to drain a 18650 battery?
Let's carry out a safe discharge. To do this you will need:
- 12 volt incandescent lamp.
- 2 wires.
- Battery to discharge.
Now all that remains is to solder the wires to the lamp and connect to the 18650 battery. A smooth discharge will occur.
You can also perform discharge using a special unit shown in the video below.
The maximum discharge current can reach up to 35 A. But it is better that this is more a myth than a reality. It is best to use the gentle mode and discharge with a current of 1 ampere.
The discharge current should not be more than 2 times the capacitance value (2C). For example, a battery with a capacity of 2000 mAh will be equal to 4000 mAh. The voltage should not be less than 2.5 volts.
