Today, special batteries are used for mobile, household appliances, tools. They differ in performance. In order for the battery to work for a long time, without failures, it is necessary to take into account the requirements of the manufacturers of the presented products.
One of the most popular types today are Li-Ion batteries. How to properly charge this type of battery, as well as the features of its operation, should be considered in detail before operating the device.
general characteristics
One of the most common types of batteries today is the Li-Ion type. Such devices are relatively inexpensive. At the same time, they are undemanding to operating conditions. In this case, the user rarely has a question about how to properly charge a cylindrical Li-Ion 18650 battery or another type.
Most often, the presented batteries are installed in smartphones, laptops, tablets and other similar devices. The presented accumulators are characterized by durability and reliability. They are not afraid of complete discharge.
One of the main features of the presented products is the absence of the "memory effect". These batteries can be recharged at almost any convenient time. The "memory effect" occurs when the battery is not fully discharged. If there is a small amount of charge left in it, the capacity of the battery will decrease over time. This will lead to an insufficiently long supply of equipment. In lithium-ion batteries, the "memory effect" is minimized.
Design
The design of a lithium-ion type battery depends on the type of device for which it is intended. For a mobile phone, a battery is used, which is called a "can". It has a rectangular shape and includes one structural element. Its nominal voltage is 3.7V.
A battery of the presented type for a laptop has a completely different design. There can be several individual battery cells in it (2-12 pieces). Each of them has a cylindrical shape. These are Li-Ion 18650 batteries. The manufacturer of the equipment indicates in detail how to charge them correctly. This design incorporates a special controller. It looks like a microchip. The controller manages the charging procedure, does not allow the nominal value of the battery capacity to be exceeded.
Modern batteries for tablets and smartphones also have a charge control function. This greatly extends battery life. It is protected from various adverse factors.
Charging features
Considering how to properly charge Li-Ion batteries of a phone, laptop and other equipment, you need to pay attention to the features of the presented device. It should be said that lithium-ion batteries do not tolerate deep discharge and overcharging. This is controlled by a special device that is added to the design (controller).
It is ideal to maintain the charge of the presented type of battery at a level of 20 to 80% of full capacity. The controller takes care of it. However, experts do not recommend leaving the device connected to charging all the time. This greatly reduces battery life. In this case, the controller is subjected to a constant load. Over time, its functionality may decrease due to this.
In this case, the controller will also not allow deep discharge. It will just turn off the battery at some point. This protective feature is essential. Otherwise, the user could accidentally overcharge or over-discharge the battery. Also in the batteries of a modern sample, high-quality protection against overheating is provided.
How the battery works
To understand how to properly charge a Li-Ion battery (new or used), you need to consider the principle of its operation. This will allow you to assess the need to control the level of discharge and charge of the device.
Lithium ions in a battery of the type presented move from one electrode to another. In this case, an electric current appears. The electrodes can be made from different materials. This indicator affects the performance of the device to a lesser extent.
Lithium ions grow on the crystal lattice of the electrodes. The latter, in turn, change their volume and composition. When the battery is charged or discharged, there are more ions on one of the electrodes. The higher the load on metal structural elements that lithium exerts, the shorter the life of the device will be. Therefore, it is better not to allow a high percentage of ion settling on one or the other electrode.
Charging Options
Before using the battery, you need to consider how to properly charge the Li-Ion battery of a smartphone, tablet and other equipment. There are several ways to do this.
One of the most correct decisions would be to use a charger. It is supplied with electronic equipment by each manufacturer.
The second option is to charge the battery from a desktop computer connected to a household network. For this, a USB cable is used. In this case, the charging procedure will be longer than when using the first method.
You can perform this procedure using the cigarette lighter in the car. Another less popular way is to charge a lithium-ion battery with a universal device. It is also called "frog". Most often, such devices are used to recharge the batteries of smartphones. The contacts of this device can be adjusted in width.
Charging a new battery
The new battery must be properly commissioned. To do this, the phone, tablet or other equipment must be completely discharged. Only when the device is turned off can it be connected to the network. The controller will not let the battery drain too much. It is he who turns off the device when the battery loses capacity to a predetermined level.
Next, you need to connect electrical equipment to the network using a standard charger. The procedure is carried out until the indicator turns green. You can leave the device online for a few more hours. This procedure is carried out several times. At the same time, you do not need to specifically discharge your phone, tablet or laptop.
Normal charging
Knowing how to properly charge Li-Ion batteries can significantly extend battery life. Experts recommend to carry out the correct procedure for this process for a new battery. After that, it is not advisable to completely discharge the battery. When the indicator shows that the battery capacity is only 14-15% charged, it must be connected to the network.
At the same time, it is also not recommended to use other devices to fill the battery capacity, except for the standard one. It has the maximum acceptable current ratings allowed for a particular battery model. Other options should only be used if absolutely necessary.
Calibration
There is one more nuance that you need to know when studying the question of how to properly charge Li-Ion batteries. Experts recommend periodically calibrating this device. It is held every three months.
First, in normal mode, you need to discharge the electrical equipment until it is turned off. Then it is connected to the network. Charging continues until the indicator turns green (the battery is 100% charged). This procedure must be followed for the correct operation of the controller.
When carrying out such a procedure, the battery circuit board determines the limits for charging and discharging. This is necessary to ensure the normal operation of the controller, to avoid failures. In this case, a regular charger is used, which is supplied by the manufacturer complete with a phone, tablet or laptop.
Storage
In order for the battery to last as long and efficiently as possible, you also need to consider how to properly charge the Li-Ion battery for storage. In some cases, a situation may arise when the device for powering equipment is temporarily not in operation. In this case, it must be properly prepared for storage.
The battery is charged up to 50%. In this state, it can be stored for a long time. However, the ambient temperature should be around 15°C. If it rises, the rate at which the battery loses its capacity will increase.
If the battery is to be stored for a sufficiently long time, it must be completely discharged and charged once a month. The battery gains 100% of its specified capacity. Then the device is discharged again and charged up to 50%. With regular carrying out of this procedure, you can store the battery for a very long time. After that, it will be completely usable.
By considering how to properly charge Li-Ion batteries, you can significantly extend the life of this type of battery.
The processes of charging and discharging any batteries proceed as a chemical reaction. However, charging lithium-ion batteries is an exception to the rule. Scientific studies show the energy of such batteries as the chaotic movement of ions. The assertions of pundits deserve attention. If it's scientifically correct to charge lithium-ion batteries, then these devices should last forever.
The facts of the loss of the useful capacity of the battery, confirmed by practice, scientists see in ions blocked by so-called traps.
Therefore, as is the case with other similar systems, lithium-ion devices are not immune from defects in the process of their application in practice.
Chargers for Li-ion designs have some similarities with devices designed for lead-acid systems.
But the main differences between such chargers are seen in the supply of high voltages to the cells. In addition, tighter current tolerances are noted, plus the elimination of intermittent or floating charge when the battery is fully charged.
Relatively powerful power supply that can be used as an energy storage device for alternative energy designs If they differ in some flexibility in terms of voltage connections / disconnections, lithium-ion system manufacturers categorically reject this approach.
Li-ion batteries and the operating rules of these devices do not allow the possibility of an unlimited overcharge.
Therefore, there is no so-called "miraculous" charger for lithium-ion batteries that can extend the service life for a long time.
It is impossible to get additional capacity of Li-ion due to impulse charge or other known tricks. Lithium-ion energy is a kind of “clean” system that accepts a strictly limited amount of energy.
Charging cobalt-blended batteries
Classic designs of lithium-ion batteries are equipped with cathodes, the structure of which is made up of materials:
- cobalt,
- nickel,
- manganese,
- aluminum.
All of them are usually charged with voltage up to 4.20V / I. The permissible deviation is no more than +/- 50 mV/I. But there are also certain types of nickel-based lithium-ion batteries that allow a charge voltage of up to 4.10V/m.
Cobalt-blended lithium-ion batteries have internal safety circuits, but this rarely saves the battery from exploding in overcharge mode. There are also developments of lithium-ion batteries, where the percentage of lithium is increased. For them, the charge voltage can reach a value of 4.30V / I and above.
Well, increasing the voltage increases the capacitance, but if the voltage goes beyond the specification, it is fraught with the destruction of the battery structure.
Therefore, for the most part, lithium-ion batteries are equipped with protective circuits, the purpose of which is to keep the established norm.
Full or partial charge
However, practice shows that most powerful lithium-ion batteries can accept a higher voltage level, provided that it is applied for a short time.
With this option, the charging efficiency is about 99%, and the cell remains cold during the entire charge time. True, some lithium-ion batteries still heat up by 4-5C when reaching a full charge.
Perhaps this is due to protection or due to high internal resistance. For such batteries, the charge should be stopped when the temperature rises more than 10ºC at a moderate charge rate.
Lithium-ion batteries in the charger on charge. The indicator shows the batteries are fully charged. Further process threatens to damage the batteries Full charging of cobalt-blended systems occurs with a threshold voltage value. In this case, the current drops by up to 3 -5% of the nominal value.
The battery will show a full charge even when a certain level of capacity is reached, which remains unchanged for a long time. The reason for this may be the increased self-discharge of the battery.
Increasing charge current and saturation charge
It should be noted that increasing the charge current does not accelerate the achievement of a state of full charge. Lithium - will reach the peak voltage faster, but the charge to full saturation of the capacity takes more time. However, charging the battery with high current quickly increases the battery capacity to about 70%.
Lithium-ion batteries do not require a full charge, as is the case with lead-acid devices. Moreover, it is this charging option that is undesirable for Li-ion. In fact, it's best not to fully charge the battery because the high voltage stresses the battery.
Selecting a lower voltage threshold or full saturation charge removal will extend the life of the Li-Ion battery. True, this approach is accompanied by a decrease in the battery energy return time.
It should be noted here: household chargers, as a rule, operate at maximum power and do not support charging current (voltage) regulation.
Manufacturers of lithium-ion battery chargers consider long life to be less of an issue than the expense of circuit complexity.
Li-ion battery chargers
Some cheap home chargers often use a simplified method. Charge the lithium-ion battery for one hour or less without going into saturation.
The ready indicator on such devices lights up when the battery reaches the voltage threshold in the first stage. The state of charge in this case is about 85%, which often satisfies many users.
This home-made charger is offered to work with different batteries, including lithium-ion batteries. The device has a voltage and current regulation system, which is already good Professional chargers (expensive) are different in that they set the charging voltage threshold lower, thereby extending the life of the lithium-ion battery.
The table shows the calculated powers when charged by such devices at different voltage thresholds, with and without saturation charge:
| Charge voltage, V/cell | Capacitance at high voltage cutoff, % | Charge time, min | Capacity at full saturation,% |
| 3.80 | 60 | 120 | 65 |
| 3.90 | 70 | 135 | 75 |
| 4.00 | 75 | 150 | 80 |
| 4.10 | 80 | 165 | 90 |
| 4.20 | 85 | 180 | 100 |
As soon as the lithium-ion battery begins to charge, there is a rapid increase in voltage. This behavior is comparable to lifting a load with a rubber band when there is a lagging effect.
The capacity will eventually be filled when the battery is fully charged. This charge characteristic is typical for all batteries.
The higher the charge current, the brighter the rubber band effect. Low temperature or the presence of a cell with high internal resistance only enhance the effect.
The structure of a lithium-ion battery in its simplest form: 1 - negative copper bus; 2 - positive tire made of aluminum; 3 - cobalt oxide anode; 4- graphite cathode; 5 - electrolyte Evaluating the state of charge by reading the voltage of a charged battery is not practical. Measuring the open circuit voltage (idle) after the battery has been sitting for a few hours is the best evaluative indicator.
As with other batteries, temperature affects idling in the same way that it affects the active material of a lithium-ion battery. , laptops and other devices is estimated by counting coulombs.
Lithium-ion battery: saturation threshold
A lithium-ion battery is not capable of absorbing excess charge. Therefore, when the battery is fully saturated, the charge current must immediately be removed.
A constant current charge can lead to metallization of lithium cells, which violates the principle of ensuring the safety of operation of such batteries.
To minimize the formation of defects, you should disconnect the lithium-ion battery as soon as possible when it reaches the peak of charge.
This battery will no longer take a charge exactly as much as it should. Due to improper charging, it has lost its main properties of an energy storage device. As soon as the charge stops, the voltage of the lithium-ion battery starts to drop. The effect of reducing physical stress is manifested.
For some time, the open circuit voltage will be distributed between unevenly charged cells with a voltage of 3.70 V and 3.90 V.
Here, the process also attracts attention when a lithium-ion battery that has received a fully saturated charge begins to charge the neighboring one (if one is included in the circuit) that has not received a saturation charge.
When Lithium-Ion batteries need to be kept in the charger at all times to ensure they are ready, you should rely on chargers that have a short-term flash charge function.
A charger with a short-term trickle charge function turns on if the open circuit voltage drops to 4.05 V / ch and turns off when the voltage reaches 4.20 V / ch.
Chargers designed for standby or standby mode often allow the battery voltage to drop to 4.00V/i and only charge Li-Ion batteries to 4.05V/i without reaching the full 4.20V/i.
This technique reduces the physical voltage inherent in the technical voltage, and helps to extend the life of the battery.
Charging cobalt-free batteries
Traditional batteries have a nominal cell voltage of 3.60 volts. However, for devices that do not contain cobalt, the value is different.
So, lithium-phosphate batteries have a rating of 3.20 volts (charge voltage 3.65V). And new lithium-titanate batteries (made in Russia) have a nominal cell voltage of 2.40V (charger 2.85).
Lithium phosphate batteries are energy storage devices that do not contain cobalt in their structure. This fact somewhat changes the conditions for charging such batteries. For such batteries, traditional chargers are not suitable, as they overload the battery with the threat of an explosion. Conversely, a charging system for cobalt-free batteries will not provide enough charge for a 3.60V traditional Li-Ion battery.
Excessive charge of the lithium-ion battery
The lithium-ion battery operates safely within specified operating voltages. However, the performance of the battery becomes unstable if it is charged beyond its operating limits.
Long-term charging of a lithium-ion battery with a voltage above 4.30V, designed for a working rating of 4.20V, is fraught with lithium plating of the anode.
The cathode material, in turn, acquires the properties of an oxidizing agent, loses its state stability, and releases carbon dioxide.
The battery cell pressure builds up and if charging continues, the internal protection device will trip at a pressure between 1000 kPa and 3180 kPa.
If the pressure increase continues after that, the protective membrane opens at a pressure level of 3.450 kPa. In this state, the lithium-ion battery cell is on the verge of exploding, and eventually this is exactly what happens.
Structure: 1 - top cover; 2 - top insulator; 3 - steel can; 4 - lower insulator; 5 - anode tab; 6 - cathode; 7 - separator; 8 - anode; 9 - cathode tab; 10 - vent; 11 - PTC; 12 - gasket The activation of the protection inside the lithium-ion battery is due to an increase in the temperature of the internal contents. A fully charged battery has a higher internal temperature than a partially charged battery.
Therefore, lithium-ion batteries are seen as safer under the condition of low-level charging. That is why the authorities of some countries require the use of Li-ion batteries in aircraft, saturated with energy no higher than 30% of their full capacity.
The internal battery temperature threshold at full load is:
- 130-150°C (for lithium-cobalt);
- 170-180°C (for nickel-manganese-cobalt);
- 230-250°C (for lithium-manganese).
It should be noted that lithium-phosphate batteries have better temperature stability than lithium-manganese batteries. Lithium-ion batteries are not the only ones that pose a danger in energy overload conditions.
For example, lead-nickel batteries are also prone to melting followed by fire if energy saturation is performed in violation of the passport regime.
Therefore, the use of chargers that are ideally suited to the battery is of paramount importance for all lithium-ion batteries.
Some conclusions from the analysis
Charging lithium-ion batteries is characterized by a simplified method compared to nickel systems. The charging circuit is straightforward, with voltage and current limits.
Such a circuit is much simpler than a circuit that analyzes complex voltage signatures that change as the battery is used.
The energizing process of lithium-ion batteries is interruptible; these batteries do not need to be completely saturated, as is the case with lead-acid batteries.
Controller circuit for low-power lithium-ion batteries. A simple solution and a minimum of details. But the scheme does not provide cycle conditions that maintain a long service life. The properties of lithium-ion batteries promise advantages in the operation of renewable energy sources (solar panels and wind turbines). As a rule, or a wind generator rarely provides a full charge of the battery.
For lithium-ion, the lack of stable charging requirements simplifies the charge controller circuit. A lithium-ion battery does not require a controller that equalizes voltage and current, as is required by lead-acid batteries.
All household and most industrial lithium-ion chargers fully charge the battery. However, existing lithium-ion battery chargers generally do not provide voltage regulation at the end of the cycle.
Hello, friends! As promised, I post a review of a miniature charging board. It is designed to charge lithium-ion batteries. Its main feature is that it is not "tied" to any specific size - 186500, 14500, etc. Absolutely any lithium-ion battery is suitable, to which you can connect the "plus" and "minus".
The fee is very small.
Despite the presence of a USB-micro input for power supply, the input "plus" and "minus" are also duplicated by terminals.
This is a very good plus. I'll explain why.
Firstly, you can take some kind of power supply and solder the wires directly to the board. It will help if the USB-micro input for some reason turns out to be faulty.
Secondly, you can take, say, 3 boards, connect three input pluses and three input minuses (you get a parallel connection), and then 3 batteries can be charged simultaneously from one power supply. And if you want to charge the batteries faster, you can connect a second and even a third charger.
By the way, battery outputs can also be parallelized.
That is, if you connect the same 3 boards not only at the input, but also at the output, you can get a very powerful charger for lithium-ion batteries. In this case, it will be charging at 3A.
But there is still one rather funny moment - the holes on the plus and minus weekends are of different diameters. Why so - I do not know.
Well, okay, this is a trifle. The main thing is that it works properly. By the way, this is what we are going to do now - checking the performance of this board.
Test 1. Cutoff upon full charge.
I carried out this test on two batteries - the original Panasonic at 3400mAh and on a fake noname at 5000mAh (and seriously - 450mAh).
A blue light on the board indicates that the battery charge is complete. The multimeter shows 4.23V. Yes, I don’t argue, 4.25V on a charged battery is, as it were, also within the normal range, but ... In general, higher than 4.2V is, as it were, not desirable. Or maybe something will change if the board is turned off?
Almost the same ideal 4.2V. Those. the battery is still charged "no frills". But what happens if you forget to remove the battery immediately after it is fully charged? Notice it's almost 6 pm in the above photo. We connect the charging back and leave it in this state for several hours.
(after 5 something hours)
I disconnected the board again so that it would not interfere with the voltage measurements on the battery. And what is the result?
There was no increase in battery voltage. Could it be battery capacity? What will happen if, instead of the original Panasonics, we charge fake nonames at 450mAh of real capacity? And so he did - first he discharged one such battery, and then set it to charge. And fell asleep.
And in the morning ... Well, we turn off the charging board and ...
So, we found out that the charge cutoff occurs when the voltage reaches 4.2V. But in the photo the voltage is lower. Those. after the end of the charge, no "refueling" occurs. Let me explain. Some chargers, after the end of the charge, continue to supply a small current (literally 10-15mA) in order to compensate for the self-discharge of the battery. It doesn't happen here. But it's not scary. Overcharging is much worse.
Let's draw a line:
- charges up to a voltage of 4.19V and cuts off
- self-discharge compensation is not performed.
Simply put, the test passed with success.
Test 2. Current.
The Chinese promised that this board is capable of charging up to 1A. Let's check? To do this, I almost discharged one of the available Panasonics (up to about 3.3V), and then put it on charge. And what do we have?
The observant will ask - “why did you remove the USB tester from the circuit? Don't you trust him?" Friends, this USB tester is good for measuring the capacity of the battery, but it is not suitable for measuring the power of the charging board. And that's why. Almost immediately, I plugged the USB tester back into the circuit and…
... and the charge current dropped by as much as 200mA. It is for this reason that I ALWAYS put dislikes on those videos where a dude takes a USB charger, sticks such a tester there, gives a load, the current output does not correspond to the declared one (for example, 2A is declared, and the output is 1.5A), and then another dispute opens with the seller, they say, how is it, 1.5A is not enough for me, give me 2A! I do not know what it is connected with, but after I took these 2 photos, I again removed the USB tester from the circuit and the charge current was restored to 1A.
So the board fully corresponds to this characteristic.
Test 3. Heating.
Well, everything is simple here - I waited 10 minutes, and then I “removed” the temperature using a pyrometer.
I won't know if this is normal or not. I'll just add an aluminum heatsink to it.
Test 4. Behavior when working with overcharged batteries.
Friends, in parallel with the review on this charging board, I also snap off a review on Panasonic. Therefore, in these two reviews, several photos will be the same. So. For the sake of testing, I discharged one of the Panasonics to an unacceptably low voltage.
And now, the hearts of those who love these Panasonics bleed. After all, they expected to see a discharge up to 2.4V, maybe even 2.2V, but not 1.77V.
I reset the tester counter and set it to charge. And here I was pleasantly surprised. I expected that due to the low resistance of the battery, the current would be prohibitively high, that even with a USB tester the current would be closer to 2A, that the charging board would work in frenzied overloads, almost on a short circuit, and other drama that makes radio amateurs sit and shaking with thoughts like “what are you doing, you bastard!” Nothing like this.
Only 80mA (OK, rounded up to 100) - the so-called "recovery" current. Fiction! Those. This board can also work with over-discharged batteries!
Or maybe she's just stupid? I do not think. After some time, when the battery took in about 35mAh, the current went off scale for 1A.
While I turned on the digital camera, while I set it up, while back and forth, the battery took in 50mAh. It is them that we will subtract from the final capacity that the USB tester will show us. But that's a completely different story.
Friends, given the price of 50r - this chip is worthy of applause.
Wisdom: the more a grandmother loves her grandson, the more this grandson takes it out on his parents.
The film company "Revealing" presents ... Thriller "Cable Cutter". Starring:
A detailed description of 18650 lithium-ion batteries, making a do-it-yourself charging device, application nuances.
TEST:
To understand if you have enough information about a lithium-ion battery:- What was the main drawback of the first 18650 battery models?
a) They exploded due to metallic lithium inside - with frequent charges, accumulations appeared on the element, leading to an explosion.
b) The battery was too bulky and inconvenient.
- What problem have manufacturers of modern 18650 models not yet got rid of?
a) The battery often overheats.
b) The battery quickly loses its charge when exposed to negative temperatures.
- In what temperature range is it desirable to store the battery?
a) + 10 - + 25 - ideal indicators. The battery does not tolerate too cold or hot rooms.
b) Store the battery at low temperatures when not in use.
c) At a temperature of + 30-45 degrees.
- Why can't I buy a charger made in China?
a) The case is too unreliable.
b) Parts of low quality, correct assembly technology is not always observed.
- At what charge level should the battery be stored?
a) Storage of 18650 should be carried out at a charge level that does not fall below 50%. Complete discharge cannot be performed.
b) Not less than 10%.
Answers:
- a) The main drawback of the first models is explosiveness. Lithium metal overgrown with growths during frequent charging and a short circuit occurred, leading to an explosion of the battery.
- b) Modern batteries do not tolerate low temperatures well - the charge drops very quickly.
- a) + 10 - + 25 - ideal indicators. Do not place the battery in other conditions.
- b) Chinese manufacturers often use low-quality parts when assembling devices, so they fail. The correct assembly technology is not always followed.
- a) If you plan to keep the battery out of work for a long time, then make sure that the charge on it does not fall below 50%, otherwise the battery will deteriorate.
Li-ion owners batteries 18650 are faced with the question of how much current to charge it. There are also difficulties in the correct operation, people do not know exactly what such batteries are afraid of, how to increase the duration of their work.
To independently assemble an electronic cigarette or a flashlight, you definitely need to study all aspects work with lithium-ion power supply.
Definition: Li-ion battery is a battery of electric current, which has become widespread among consumer electronics since 1991. It was this year that Sony Corporation presented the product to a wide market.
Answers to 5 frequently asked questions
- What are lithium-ion batteries used for?
- As a power source. Such batteries are often used for various mobile phones, camcorders, laptops, for recharging electric vehicles or modern electronic cigarettes.
- Do models have flaws?
- The main drawback of the model was that the first developments literally exploded. This is due to the fact that manufacturers have placed inside the anode, consisting of metallic lithium. When a large number of charges and discharges occur, formations appear on the anode, leading to a short circuit of the electrodes. The result is a fire, and then an explosion. This issue has been resolved for now.
- How was the explosion problem solved?
— To secure the design, the scientists replaced the core with graphite, and got rid of the problem with explosions. But difficulties remained with the cathode caused by the cobalt oxide construction. If the operational characteristics were violated, then the explosions were repeated. That is why it was necessary to ensure that the device was not subjected to overcharging. It was extremely inconvenient for users to constantly monitor the level of charge and the developers had to modify the device again. Modern models are safe. When the developers began to use lithium-ferro-phosphate batteries, they managed to get rid of this problem. A modern device is produced in such a way that overcharging and overheating is impossible.
- Are current models flawed?
- The charge is lost if the battery is exposed to low temperatures.
- If the battery is not used for a long time, will it deteriorate?
- If you do not lower the level of rarefaction below 50%, then it will not deteriorate.
3 battery advantages
Li-ion accumulators have a number of positive aspects because of which they gained popularity:
- Very large capacity battery.
- Little self-discharge.
- No special maintenance required.
Charging - 5 nuances
Charger Look at the picture of the original charger device. A charger designed for lithium-ion batteries is very similar to a lead-acid type of battery. The difference is that the lithium-ion battery there are high voltages on each bank and severe voltage tolerance requirements.
This is interesting! The battery is called a "can" because of the similarity with aluminum cans, which produce soft drinks.
"Banks" Most Popular Items food with this form - 18650. The battery received this name because of its size: diameter - 18 mm, height - 65 mm. When is lead-acid charging batteries, minor inaccuracies in voltage indications are allowed. But with lithium-ion devices, everything is much more specific. When it happens charger, and the voltage increases to 4.2 volts, the voltage to the element must be stopped immediately. The error is only 0.5 volts.
Chinese exercise There are a large number on the market Chinese chargers designed for batteries of different materials. Without compromising performance, ion batteries are charged with a current of 0.8 A. But the voltage in the bank will have to be very clearly controlled. When the value is 4.2 Volts, immediately stop charging. But in the event that the bank is embedded controller, then do not worry about it, because the device will do everything on its own.
Charging 4.2 Volts
As charger for a lithium-ion battery, a voltage stabilizer is used, current is limited at the very beginning of charging. It is necessary to use an exceptionally stable voltage, and limit the current at the very beginning of the charging process. Charging should be completed at the moment when the stable voltage is 4.2 volts, there is no current, or its value is very small - in the region of 5-7 mA.
Oxidation When a rod of graphite, then the voltage should not exceed 4.1 V per cell. If this rule is neglected, the energy density will increase greatly, and the oxidation processes of the device will begin. As a result, the battery will fail. To avoid oxidation, modern models are equipped with additives - graphite not in pure form. But similar models can still be found by chance.
How to properly charge Li-ion batteries. Parallel connection of batteries.
Homemade charger at home (do it yourself) - 1 diagram
For charging 18650 they acquire universal charging, and constantly use a multimeter to find out the necessary parameters. But such a device is quite expensive. The minimum price is 2700 rubles.
Instead, you can spend just a few hours and assemble a charger device on one's own. The advantages of such an assembly are low cost, reliability, automatic battery shutdown. All parts used for assembly can be found in the garage of any radio amateur. If something is missing, it can be bought at the nearest radio store. You will have to spend a maximum of 300 rubles on components.
If scheme correctly assembled, then there is no need for additional configuration - it will immediately be ready for use.
You need to use the following wiring diagram:
Scheme
The good news is that if you set stabilizer to the desired radiator, then the battery is charged without fear that the charge will light up. And this definitely cannot be said about Chinese chargers, which sin with this unpleasant consequence.
The principle of operation - 4 nuances
- to start battery must be charged using direct current, which is determined by the resistance of the resistor R4;
- after battery will receive a voltage of 4.2 volts, the device switches to DC charging;
- when the current drops to the minimum values, the LED will stop burning;
- current that recharges the lithium-ion battery, should not exceed 10% of the total battery capacity. Thus, the service life of the batteries is increased. If the resistor R4 has a rating of 11 ohms, then the circuit current should be 100 mA. If the resistance is 5 ohms, then the charging current should be 230 mA.
It is also important to know 3 nuances about "life extension" 18650
- If battery will need to be left without work for some time, then it is advisable to store the batteries separately from the device that they will power. If the cell is fully charged, then over time it will lose some of its charge. In the case when the element is charged very little, or completely discharged, then the performance may completely disappear. This is especially noticeable during a long hibernation.
- Storage 18650 should be carried out at a charge level that does not fall below 50%. Under no circumstances should the cell be fully charged and recharged. This equipment has no memory effect. Charging must be done before the charge runs out completely. Thus, battery life will be extended.
- Battery it is forbidden to leave in too cold or hot rooms. A suitable storage temperature is + 10 - + 25 degrees Celsius. If you place the battery in the cold, then not only will the operating time be reduced, but the chemical system will also deteriorate. Everyone must have noticed that when using a mobile phone in winter, the charge batteries drops sharply.
How to avoid 4 mistakes when using and charging a lithium-ion battery
- In the event that you decide to recharge the lithium-ion battery using a store charge, you will have to make sure that it is not made in China. Typically, such devices are assembled from the cheapest materials, and the required technology is not always observed in them. As a result, this can lead to very sad consequences: fire and explosion.
- If you wish to assemble device, then you need to use a current to charge the battery, which is 10% of the battery capacity. The percentage may be higher, but not exceed 20%.
- When using ion batteries, do not violate the rules of storage and operation, otherwise overheating, fire and explosion may occur.
- If you follow all the rules operation, as well as the correct storage conditions, then the battery life will be extended.
Top 3 Best 18650 Battery Chargers
For high-quality battery charging, you should purchase good devices, which is already loved by many users.
- Nitecore Digicharger D4 - suitable for charging multiple batteries at once. Extremely easy to use.
- Nitecore i2 is one of the best options for modern devices. Clear and easy to use.
- Basen B21 is a universal device for different types of batteries.
Batteries play an important role in any off-line machine. Rechargeable batteries are quite expensive due to the fact that you need to purchase a charger with them. Batteries use different combinations of conductive materials and electrolytes - lead-acid, nickel-cadmium (NiCd), nickel-metal hydride (NiMH), lithium-ion (Li-ion), lithium-ion polymer (Li-Po).
I use lithium-ion batteries in my projects, so I decided to make my own charger for lithium 18650 batteries, and not buy expensive ones, so let's get started.
Step 1: Video
The video shows the assembly of the charger.
link to youtube
Step 2: List of electrical components
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List of components needed to assemble the 18650 battery charger:
- Charger module based on TP4056 chip with battery protection
- Voltage stabilizer 7805, you will need 1 piece
- Capacitor 100 nF, 4 pcs (not needed if there is a 5V power supply)
Step 3: List of Tools
To work, you will need the following tools:
- hot knife
- Plastic box 8x7x3 cm (or close in size)
Now that all the necessary tools and components are ready for work, let's take a look at the TP4056 module.
Step 4: Li-io battery charger module based on TP4056 chip
A little more about this module. There are two versions of these modules on the market: with and without battery protection.
The breakout board containing the protection circuit monitors the voltage with the power supply filter DW01A (Battery Protection Integrated Circuit) and FS8205A (N-Channel Transistor Module). Thus, the breakout board contains three integrated circuits (TP4056+DW01A+FS8205A), while the charger module without battery protection contains only one integrated circuit (TP4056).
TP4056 is a charging module for single-cell Li-io batteries with a linear charge of constant current and voltage. The SOP package and few external components make this module an excellent choice for DIY electrical applications. It charges over USB just as well as through a regular power bank. The pinout of the TP4056 module is attached (Figure 2), as is the Charging Cycle Chart (Figure 3) with constant current and constant voltage curves. Two diodes on the breakout board indicate the current charge status - charging, charging termination, etc. (Fig. 4).
In order not to damage the battery, 3.7 V Li-ion batteries should be charged at a constant current value of 0.2-0.7 of their capacity until the output voltage reaches 4.2 V, after which it will be charged at a constant voltage and gradually decreasing (up to 10% of the initial value) current. We cannot interrupt the charge at 4.2V, as the charge level will be 40-80% of the full capacity of the battery. The TP4056 module is responsible for this process. Another important point is that the resistor connected to the PROG pin determines the charging current. In modules on the market, a 1.2KΩ resistor is usually connected to this pin, which corresponds to a charging current of 1A (Fig. 5). To get other values \u200b\u200bof the charging current, you can try to put other resistors.
DW01A is a battery protection integrated circuit, Figure 6 shows a typical wiring diagram. MOSFETs M1 and M2 are connected externally by an FS8205A integrated circuit.
These components are installed on the TP4056 Lithium-Ion Battery Charger Breakout Board, referenced in Step 2. We only need to do two things: apply a voltage in the range of 4-8V to the input connector, and connect the battery terminals with the + and - terminals. module TP4056.
After that, we will continue to assemble the charger.
Step 5: Wiring Diagram
To complete the assembly of electrical components, we solder them in accordance with the diagram. I've attached a diagram in Fritzing and a photo of the physical connection.
- + we connect the contact of the power connector to one of the contacts of the switch, and - the contact of the power connector is connected to the GND pin of the stabilizer 7805
- The second contact of the switch is connected to the Vin pin of the stabilizer 7805
- Install three 100nF capacitors in parallel between the Vin and GND pins of the voltage regulator (use a breadboard for this)
- Install a 100nF capacitor between the Vout and GND pins of the voltage regulator (on the breadboard)
- Connect the Vout pin of the voltage regulator to the IN+ pin of the TP4056 module
- Connect the GND pin of the voltage regulator to the IN pin of the TP4056 module
- Connect the + terminal of the battery compartment to the B+ pin of the TP4056 module, and the - terminal of the battery compartment to the B-pin of the TP4056 module.
This completes the connections. If you are using a 5V power supply, skip all steps with connections to the 7805 voltage regulator, and connect the + and - of the power supply directly to the IN+ and IN- pins of the TP4056 module, respectively.
If you use a 12V power supply, the 7805 will heat up when passing 1A current, this can be fixed with a heat sink.
Step 6: Assembly Part 1: Cut Holes in the Case
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In order to properly fit all the electrical components in the case, you need to cut holes in it:
- Use a knife blade to mark the boundaries of the battery compartment on the case (Fig. 1).
- Use a hot knife to cut a hole along the marks made (fig. 2 and 3).
- After cutting the hole, the case should look like in Fig.4.
- Mark the place where the USB connector of the TP4056 module will be located (Fig. 5 and 6).
- Use a hot knife to cut a hole in the case for the USB connector (Fig. 7).
- Mark the places on the case where the diodes of the TP4056 module will be located (Fig. 8 and 9).
- Use a hot knife to cut holes for the diodes (Fig. 10).
- In the same way, make holes for the power connector and switch (Fig. 11 and 12)
Step 7: Assembly Part 2: Install Electrical Components
Follow the instructions to install the components in the chassis:
- Install the battery drawer so that the mounting points are outside the drawer/chassis. Glue the compartment with a glue gun (Fig. 1).
- Reinstall the TP4056 module so that the USB connector and diodes fall into the corresponding holes, fix with hot glue (Fig. 2).
- Replace voltage regulator 7805, secure with hot glue (Fig. 3).
- Install the power connector and switch in their places, fix them with hot glue (Fig. 4).
- The location of the components should look the same as in Fig.5.
- Secure the bottom cover in place with screws (fig.6).
- Later, I covered the rough edges left by the hot knife with black duct tape. They can also be smoothed out with sandpaper.
The completed charger is shown in Figure 7. now it must be tested.
Step 8: Test
Place the discharged battery in the charger. Turn on the power to the 12V socket or USB. The red diode should blink, which means that the charging process is in progress.
When the charge is complete, the blue diode should light up.
I am attaching a photo of the charger in the process of charging and a photo with a charged battery.
This completes the work.
