Which battery can be charged. How to charge a car battery

Many people know that portable energy sources are rechargeable and ordinary. It is believed that if the batteries are knocked against the wall or slightly changed in shape, then their service life can be extended by several hours. And this is absolutely true. However, there are other proven and original ways do it yourself at home.

How to know if you can recharge

The battery differs from an ordinary battery with a capacity of mAh. Often the manufacturer makes this inscription in large letters. The higher this indicator, the longer the battery will work.

If during the purchase you saw the inscription "do not recharge", then the element not rechargeable... Another difference is cost. Battery devices cost much more than conventional energy cells. Moreover, the cost is formed from the cycles of recharging and power.

It is noteworthy that craftsmen have learned to charge ordinary devices as well. To do this, they came up with a lot of ways.

You should immediately pay attention to the fact that you can independently recharge only alkaline (alkaline) cells. Saline is not suitable for this. In addition, recharging them can be dangerous and result in to very undesirable consequences: explosion, contact of electrolyte in the eyes, etc.

Charging can be done different ways... Therefore, you do not need to throw away the device immediately after it has become unusable.

Use of special devices

There are many special chargers on the market today, such as the Battery Wizard. With the help of such a device, you can charge ordinary finger devices several times. Consumers speak of this device as a profitable and economical purchase.

For recharging, the batteries are placed inside a special design, which can have different shapes: square, rectangular, round, etc.

Then the device is connected to a 220 V power supply. After the elements become slightly warm, they need pull out immediately... If overheating occurs, this will lead to sad consequences.

Better buy special rechargeable batteries and a charger included. Also pay attention to the manufacturer.

Danger of charging batteries

A large number of companies produce galvanic cells... You can buy them at any electronic goods and household equipment store. The AA batteries contain caustic alkali. In a confined space, when an electric current passes, the device can easily explode.

If the battery easily survives the charge / discharge cycle, then its capacity will significantly decrease with subsequent recharges. In addition, electrolyte often starts to leak, which can cause damage to the device installed in the battery.

Is it possible to extend the service life

Ordinary salt-type batteries do not function very well in freezing temperatures and heat. Therefore, it is better not to use them in such weather conditions. The electrolyte inside is converted to gas or freezes, which adversely affects its conductivity.

A discharged battery will work a little longer if its case lightly crush with pliers... But this must be done as carefully as possible in order to prevent damage.

Reagents often clump into small lumps that prevent the reaction from proceeding smoothly. inside the battery... In order to facilitate the process, you can knock the finger-type battery on some solid surface. This will add about 6-7 percent power to the element.

You should also pay attention to the fact that alkaline devices tend to self-discharge. Therefore, when buying, you should take into account the date of manufacture... Old elements will quickly deteriorate.

To achieve maximum battery life, not worth installing in one device different types... The same goes for installing new elements to old ones. It is best to always have an extra kit in stock. When one has lost its charge, it can be quickly and easily replaced. In this case, you will not need to think about whether the batteries can be charged.

Often we miss good shots in the forest or at sea, we can be late or stumble in the dark, because a simple battery from a camera, clock or flashlight suddenly runs out. When exactly the charge will be used up, it is difficult to say, except that this is not a Duracell model with an indicator. But don't despair! Thanks to a few tips, you can avoid unpredictable situations and take the planned photos with a digital camera, find out the exact time, illuminate the road, etc. In this article, we will show you how to charge batteries at home without a charger, which will make life much easier in unpredictable situations.

Be aware that you can use a special charger to charge alkaline batteries. charger capable of relatively quickly restoring a discharged object. But each charge session will reduce its life by about 1/3. In addition, leaks are possible.

Note! At home you can charge: alkaline (alkaline) penlight batteries... Not allowed: saline. The possibility of leakage or even explosion is not excluded!

Charging can be done in a variety of ways. Therefore, you should not throw out the element as soon as it has ceased to serve. A few recommendations - and he is back in the ranks. The first method, using which you can independently charge finger-type batteries without a charger. We connect the power supply to the network. Next, using the wires for connection, we connect the spent battery to the unit. Do not forget about the polarity: the plus is connected to the plus, and the minus is connected to the minus. It is quite easy to find where the “- \ +” of the discharged object is: they are marked on the case.

Having connected the battery to the power source, we wait until it heats up to fifty degrees, and turn off the power. Then we wait a few minutes for the heated object to cool down. Otherwise, it may explode. Then, while the AA is still warm, it needs to be charged in a different way. It consists in the following: we connect the power supply to electricity and disconnect. This takes about 120 seconds. Next, we place the object for charging in the “freezer” for 10 minutes, then we take it out and wait 2-3 minutes for it to warm up. That's it, the charge is restored right at home without a charger! You can safely use it for the same computer mouse.

Main rules:

1. The charge is not workable if you arrange + and - in a different way. On the contrary, the battery will run out even faster.
2. Charge the object at home 1-2 times.
3. In the way described above, you can only charge simple finger-type alkaline batteries.
4. The charge is feasible in any ambient temperature conditions.

Another charging method is the conventional heating method. But it is fraught with consequences (explosion). This way, again, small alkaline batteries can be recovered at home. You can also charge them more in a simple way- place the discharged objects in hot water, but for no more than 20 seconds, otherwise sad results are possible. Another uncomplicated way is to flatten or reduce the volume of the element with your own hands. So you can charge various finger-type batteries. There is an example when a person, upon expiration of the charge of a casting-ion battery, simply took out and trampled it, after which the charge indicators showed one hundred percent.

You can also restore the charge without a charger like this: we make 2 holes with an awl near each coal rod, three-quarters deep from the height of the element itself. Pour liquid into them, and seal them, covering them with resin or plasticine. You can fill in not just a liquid, but an eight to ten percent solution of hydrochloric acid or double vinegar. Fill the solution several times for sufficient saturation. This method allows you to charge up to seventy to eighty percent of the initial capacity.

Video instruction on how to restore Duracell using telephone charging

Another way to charge the product: open the cover of the element with a knife. If the zinc cylinder, object shaft, and carbon powder are intact, then immerse the object in a salt solution. Its ratio is as follows: 2 tablespoons of table salt for several glasses of liquid. Next, boil the solution together with the element for about ten to fifteen minutes. Then we return to the place the gaskets responsible for sealing, and cover with wax or plasticine.

Alternative charging method

In this article, we have shown you how to charge your batteries at home without a charger. The suggested tips apply only to finger-type batteries, since, unlike the little fingers, flat (tablets) used for lasers, they are most often used in everyday life. You can now properly charge required elements even if there is no electricity!

Also read:

When operating a car with serviceable electrical equipment, problems associated with the battery of this car usually do not arise. Of course, if you do not leave powerful consumers of electricity on for a long time when the car engine is not running. But it is worth blowing out the fuse that protects the generator excitation circuit, and the next attempt to start the car engine will not be crowned with success. After that, a previously irrelevant question will arise before the car owner: "how to charge the battery correctly?" With the availability of a charger, nothing complicated by itself correct charging does not represent a car battery at home. Charging the car battery with an automatic charger is the most simple and does not need control over the process.

The car battery (ACB) is used to start the car engine and as an auxiliary source of electricity when the car engine is not running.

Battery health assessment

The fact that the starter of the car "sluggishly" turns, not necessarily a consequence of the fact that the automobile chemical source of electricity is depleted. Therefore, before dragging the car battery for charging, it is recommended to check it.

Measurements are taken when the car engine is not running. A fully charged car battery has an electrolyte density of 1.27 to 1.29 g / cm 3 and a terminal voltage from 12.3 to 12.9 V. When 70% of the charge remains in it, its electrolyte density will be from 1.23 to 1.25 g / cm 3, and the voltage from 12.0 to 12.1 V. A half-discharged current source will have an electrolyte density of 1.16 to 1.18 g / cm 3 and show a voltage from 11.8 to 12, 0 V. Fully discharged, it will have a density of 1.11 to 1.13 g / cm 3, and the voltage will drop below 11 V.

Preparing the battery for charging

In order to properly charge the battery at home, follow this sequence:

Charging methods

There are three ways to properly charge the battery:

The first two ways to charge the battery have both pros and cons. The first method consists in connecting the battery to a source of electricity with a constant current strength of not more than 16.2 V. The current strength when charging for 20 hours can be calculated if the battery capacity is divided by 20 hours. For example, your machine has a 50 Ah battery, then 50 Ah / 20 h = 2.5A. With a 10 hour charge, to determine the current strength of the battery charge, the capacity is divided by 10 hours. That is, in order to properly charge the same battery in 10 hours, you need a charging current of 5 A. One of the most important advantages of this method is that the battery is fully charged. Among the disadvantages can be noted the need to stabilize the current strength, significant gas evolution, and heating of the electrolyte.

It is recommended to charge in this way in two stages - first, make the charging current equal to 1/10 of the nominal capacity, and after reaching the voltage of one cell of 2.4 V, reduce it by 2 times. The end of charging is determined by the appearance of intense gassing - "boiling" of the electrolyte.

Alternative

The second method is to stabilize the charging voltage, while the current strength varies depending on the resistance of the battery. This technique allows you to charge the battery up to 85–90%. The advantages of the method:

• quick bringing the battery into working condition;
• most of the energy consumed at the beginning of the process is spent on restoring the active mass of the plates.

The main disadvantage is the strong heating of the electrolyte due to great strength current at the beginning of charging. Equalizing charge is designed to eliminate the consequences of deep discharges. It very well eliminates the increasing sulfation of the electrodes.

The forced technique is used to quickly restore the operating state of the source after a deep discharge. Allows an increase in current at the beginning of charging up to 70% of the value of the nominal capacity, but not more than half an hour. The next 45 minutes the charging current is reduced to half of the rated capacity. For another 1.5 hours, the charge goes with a current equal to 30% of the nominal capacity. This charging requires mandatory monitoring of the electrolyte temperature. If the temperature rises to 45 ◦ C, stop charging.

Use the method of forced charging of the battery on the trail as little as possible, since it regular use significantly reduces its service life.

About battery capacity

Among car owners, there is an opinion that it is unacceptable to install a battery with an increased capacity on a car, since with a larger capacity, the car battery allegedly will not have time to charge. However, the amount of energy spent on starting the car engine does not depend on the battery capacity. Therefore, with a working generator, it will be replenished in a battery of larger and smaller capacity at the same time. This means that installing a battery with a capacity greater than the recommended one on a car will not do any harm.

Charging device

The charger (charger) serves to charge electric batteries from the mains alternating current... The charger consists of a voltage converter (transformer or pulse rectifier), a voltage stabilizer, a controller that regulates the charging current and sometimes an indication unit consisting of dial or LED ampere-voltmeters. Chargers differ in the type of rechargeable batteries, their operating voltage and capacity.

Designation of the charger for car batteries: X B / C, where X is the name of the charger, B is the maximum capacity of the rechargeable battery in Ampere-hours, C is the maximum operating voltage of the rechargeable battery in volts. If the charger has a B value exceeding 170 Ah, then it can be used not only for charging, but also to help start the car engine.

Assessing the characteristics of a particular charger is difficult without understanding how an exemplary charge of a li-ion battery should actually flow. Therefore, before proceeding directly to the circuits, let's recall the theory a little.

What are lithium batteries

Depending on what material the positive electrode of a lithium battery is made of, there are several varieties of them:

• with lithium cobaltate cathode;
• with a cathode based on lithiated iron phosphate;
• based on nickel-cobalt-aluminum;
• based on nickel-cobalt-manganese.

All these batteries have their own characteristics, but since these nuances are not of fundamental importance for the general consumer, they will not be considered in this article.

Also, all li-ion batteries are produced in various standard sizes and form factors. They can be both in a case design (for example, the popular 18650 today) and in a laminated or prismatic design (gel-polymer batteries). The latter are hermetically sealed bags made of a special film, in which the electrodes and electrode mass are located.

The most common sizes of li-ion batteries are shown in the table below (they all have a nominal voltage of 3.7 volts):

Designation	Standard size	Similar size
XXYY0, where XX- indication of the diameter in mm, YY- length value in mm, 0 - reflects the execution in the form of a cylinder	10180	2/5 AAA
	10220	1/2 AAA (Ø corresponds to AAA, but half the length)
	10280
	10430	AAA
	10440	AAA
	14250	1/2 AA
	14270	Ø AA, length CR2
	14430	Ø 14 mm (like AA), but shorter
	14500	AA
	14670
	15266, 15270	CR2
	16340	CR123
	17500	150S / 300S
	17670	2xCR123 (or 168S / 600S)
	18350
	18490
	18500	2xCR123 (or 150A / 300P)
	18650	2xCR123 (or 168A / 600P)
	18700
	22650
	25500
	26500	WITH
	26650
	32650
	33600	D
	42120

Internal electrochemical processes proceed in the same way and do not depend on the form factor and design of the battery, therefore everything said below applies equally to all lithium batteries.

How to properly charge lithium-ion batteries

The most correct way to charge lithium batteries is to charge in two stages. This is the method used by Sony in all of its chargers. Despite the more sophisticated charge controller, this provides a fuller charge for li-ion batteries without compromising their lifespan.

Here we are talking about a two-stage charging profile of lithium batteries, abbreviated as CC / CV (constant current, constant voltage). There are also options with pulsed and step currents, but they are not considered in this article. You can read more about charging with a pulsed current.

So, let's consider both stages of charging in more detail.

1. At the first stage constant charging current must be ensured. The current value is 0.2-0.5C. For accelerated charging, it is allowed to increase the current to 0.5-1.0C (where C is the capacity of the battery).

For example, for a battery with a capacity of 3000 mA / h, the nominal charge current at the first stage is 600-1500 mA, and the accelerated charge current can be in the range of 1.5-3A.

To provide a constant charging current of a given value, the charger circuit (charger) must be able to raise the voltage at the battery terminals. In fact, at the first stage, the charger works like a classical current stabilizer.

Important: if you plan to charge batteries with a built-in protection board (PCB), then when designing the memory circuit, you must make sure that the open circuit voltage of the circuit can never exceed 6-7 volts. Otherwise, the protection board may be damaged.

At the moment when the voltage on the battery rises to a value of 4.2 volts, the battery will gain approximately 70-80% of its capacity (the specific value of the capacity will depend on the charge current: with accelerated charging it will be slightly less, with nominal - slightly more). This moment is the end of the first stage of charging and serves as a signal for the transition to the second (and last) stage.

2. Second stage of charging- this is a battery charge with constant voltage, but gradually decreasing (falling) current.

At this stage, the charger maintains a voltage of 4.15-4.25 volts on the battery and controls the current value.

As the capacity increases, the charging current will decrease. As soon as its value decreases to 0.05-0.01C, the charging process is considered complete.

An important nuance of the correct charger is its complete shutdown from the battery after charging. This is due to the fact that for lithium batteries it is extremely undesirable for them to be under increased voltage for a long time, which usually provides a charger (i.e. 4.18-4.24 volts). This leads to an accelerated degradation of the chemical composition of the battery and, as a consequence, a decrease in its capacity. A long-term stay means tens of hours or more.

During the second stage of charging, the battery manages to gain approximately another 0.1-0.15 of its capacity. The total battery charge thus reaches 90-95%, which is an excellent indicator.

We have covered two main stages of charging. However, coverage of the issue of charging lithium batteries would be incomplete if one more stage of charging was not mentioned - the so-called. precharge.

Pre-charge stage (pre-charge)- this stage is used only for deeply discharged batteries (below 2.5 V) to bring them back to normal operating conditions.

At this stage, the charge is provided direct current reduced value until the battery voltage reaches 2.8 V.

A preliminary stage is necessary to prevent swelling and depressurization (or even explosion with fire) of damaged batteries, for example, having an internal short circuit between the electrodes. If a large charge current is immediately passed through such a battery, this will inevitably lead to its warming up, and then how lucky.

Another benefit of precharging is to preheat the battery, which is important when charging at low ambient temperatures (in an unheated room during the cold season).

Intelligent charging should be able to monitor the voltage on the battery during the preliminary stage of charging and, if the voltage does not rise for a long time, conclude that the battery is faulty.

All stages of charging a lithium-ion battery (including the precharge stage) are schematically depicted in this graph:

Exceeding the rated charging voltage by 0.15V can cut the battery life in half. Lowering the charge voltage by 0.1 volt reduces the capacity of a charged battery by about 10%, but significantly extends its life. The voltage of a fully charged battery after removing it from the charger is 4.1-4.15 volts.

To summarize the above, we will outline the main theses:

1. What current to charge a li-ion battery (for example, 18650 or any other)?

The current will depend on how quickly you would like to charge it and can range from 0.2C to 1C.

For example, for a battery of size 18650 with a capacity of 3400 mAh, the minimum charge current is 680 mA, and the maximum is 3400 mA.

2. How long does it take to charge, for example, the same 18650 rechargeable batteries?

The charging time directly depends on the charging current and is calculated by the formula:

T = C / I charge.

For example, the charging time of our 3400 mAh battery with a current of 1A will be about 3.5 hours.

3. How to properly charge the lithium polymer battery?

Any lithium batteries are charged the same way. It doesn't matter if it is lithium polymer or lithium ion. For us consumers, there is no difference.

What is a protection board?

The protection board (or PCB - power control board) is designed to protect against short circuit, overcharge and overdischarge of the lithium battery. As a rule, overheating protection is also built into the protection modules.

For safety reasons, it is prohibited to use lithium batteries in household appliances if they do not have a built-in protection board. Therefore, all batteries from cell phones always have a PCB board. The output terminals of the battery are located directly on the board:

These boards use a six-legged charge controller based on specialized mikruh (JW01, JW11, K091, G2J, G3J, S8210, S8261, NE57600, etc. analogs). The task of this controller is to disconnect the battery from the load when the battery is fully discharged and disconnect the battery from charging when it reaches 4.25V.

For example, here is a diagram of the BP-6M battery protection board, which was supplied to the old Nokia phones:

If we talk about 18650, then they can be produced with or without a protection board. The protection module is located in the area of ​​the negative terminal of the battery.

The board increases the length of the battery by 2-3 mm.

Batteries without a PCB are usually included in batteries with their own protection circuits.

Any battery with protection can easily turn into a battery without protection, you just need to gut it.

To date, the maximum capacity of the 18650 battery is 3400mAh. Protected batteries must be marked on the case ("Protected").

Do not confuse PCB with power charge module (PCM). If the former serve only to protect the battery, the latter are designed to control the charging process - they limit the charge current at a given level, control the temperature and, in general, provide the entire process. The PCM board is what we call the charge controller.

I hope now there are no questions left, how to charge an 18650 battery or any other lithium battery? Then we turn to a small selection of ready-made circuitry solutions for chargers (those same charge controllers).

Charging schemes for li-ion batteries

All circuits are suitable for charging any lithium battery, it remains only to decide on charging current and element base.

LM317

Diagram of a simple charger based on the LM317 microcircuit with a charge indicator:

The circuit is simple, the whole setup is reduced to setting the output voltage of 4.2 volts using a trimmer resistor R8 (without a connected battery!) And setting the charge current by selecting resistors R4, R6. The power of the resistor R1 is at least 1 Watt.

As soon as the LED goes out, the charging process can be considered complete (the charging current will never decrease to zero). It is not recommended to keep the battery in this charge for a long time after it is fully charged.

The lm317 microcircuit is widely used in various voltage and current stabilizers (depending on the switching circuit). It is sold on every corner and costs just a penny (you can take 10 pieces for only 55 rubles).

LM317 comes in different housings:

Pin assignment (pinout):

Analogs of the LM317 microcircuit are: GL317, SG31, SG317, UC317T, ECG1900, LM31MDT, SP900, KR142EN12, KR1157EN1 (the last two are of domestic production).

The charging current can be increased to 3A if you take the LM350 instead of the LM317. True, it will be more expensive - 11 rubles / piece.

The PCB and schematic assembly are shown below:

The old Soviet transistor KT361 can be replaced with a similar one pnp transistor(for example, KT3107, KT3108 or bourgeois 2N5086, 2SA733, BC308A). It can be removed altogether if the charge indicator is not needed.

Disadvantage of the circuit: the supply voltage must be within 8-12V. This is due to the fact that for normal operation of the LM317 microcircuit, the difference between the voltage on the battery and the supply voltage must be at least 4.25 volts. Thus, it will not work from the USB port.

MAX1555 or MAX1551

The MAX1551 / MAX1555 are dedicated Li + battery chargers that can be powered by USB or a separate power adapter (such as a phone charger).

The only difference between these microcircuits is that the MAX1555 gives a signal for the indicator of the charging process, and the MAX1551 gives a signal that the power is on. Those. 1555 in most cases is still preferable, so 1551 is now difficult to find on sale.

A detailed description of these microcircuits from the manufacturer -.

The maximum input voltage from the DC adapter is 7 V, when powered from USB - 6 V. When the supply voltage drops to 3.52 V, the microcircuit is turned off and the charge stops.

The microcircuit itself detects at which input the supply voltage is present and is connected to it. If the power is supplied via the YUSB bus, then the maximum charge current is limited to 100 mA - this allows you to stick the charger into the USB port of any computer without fear of burning the south bridge.

When powered by a separate power supply, the typical charging current is 280mA.

The microcircuits have built-in overheating protection. Even so, the circuit continues to operate, decreasing the charge current by 17mA for every degree above 110 ° C.

There is a pre-charge function (see above): as long as the voltage on the battery is below 3V, the microcircuit limits the charge current to 40 mA.

The microcircuit has 5 pins. Here is a typical connection diagram:

If there is a guarantee that the voltage at the output of your adapter will under no circumstances exceed 7 volts, then you can do without the 7805 stabilizer.

The USB charging option can be assembled, for example, on this one.

The microcircuit does not need external diodes or external transistors. Generally, of course, gorgeous mikruhi! Only they are too small, it is inconvenient to solder. And they are also expensive ().

LP2951

The LP2951 stabilizer is manufactured by National Semiconductors (). It provides the implementation of the built-in current limiting function and allows you to form a stable level of the charging voltage of the lithium-ion battery at the output of the circuit.

The charge voltage is 4.08 - 4.26 volts and is set by resistor R3 when the battery is disconnected. The tension is held very precisely.

The charge current is 150 - 300mA, this value is limited by the internal circuits of the LP2951 microcircuit (depending on the manufacturer).

Use a diode with a small reverse current. For example, it can be any of the 1N400X series that you can purchase. The diode is used as a blocking diode to prevent reverse current from the battery into the LP2951 microcircuit when the input voltage is disconnected.

This charging provides a fairly low charging current, so that any 18650 battery can be charged overnight.

The microcircuit can be bought both in a DIP package and in a SOIC package (the cost is about 10 rubles per piece).

MCP73831

The microcircuit allows you to create the right chargers, and it is also cheaper than the hyped MAX1555.

A typical connection diagram is taken from:

An important advantage of the circuit is the absence of low-resistance power resistors that limit the charge current. Here the current is set by a resistor connected to the 5th pin of the microcircuit. Its resistance should be in the range of 2-10 kOhm.

The complete charger looks like this:

The microcircuit heats up quite well during operation, but this does not seem to interfere with it. Performs its function.

Here's another option printed circuit board with smd LED and micro USB connector:

LTC4054 (STC4054)

Highly simple circuit, great option! Allows charging with current up to 800 mA (see). True, it tends to get very hot, but in this case, the built-in overheating protection reduces the current.

The circuit can be greatly simplified by throwing out one or even both LEDs with a transistor. Then it will look like this (you must admit, it's nowhere easier: a pair of resistors and one condenser):

One of the PCB options is available from. The board is designed for elements of standard size 0805.

I = 1000 / R... It is not worth setting a large current right away, first look at how much the microcircuit will heat up. For my own purposes, I took a 2.7 kOhm resistor, while the charge current turned out to be about 360 mA.

A radiator for this microcircuit is unlikely to be able to adapt, and it is not a fact that it will be effective due to the high thermal resistance of the crystal-case transition. The manufacturer recommends making the heat sink "through the pins" - making the tracks as thick as possible and leaving the foil under the microcircuit case. In general, the more "earthen" foil is left, the better.

By the way, most of the heat is dissipated through the 3rd leg, so you can make this track very wide and thick (fill it with excess solder).

The package of the LTC4054 chip can be labeled LTH7 or LTADY.

LTH7 differs from LTADY in that the first one can lift a badly dead battery (on which the voltage is less than 2.9 volts), and the second one cannot (you need to swing it separately).

The microcircuit came out very successful, therefore it has a bunch of analogues: STC4054, MCP73831, TB4054, QX4054, TP4054, SGM4054, ACE4054, LP4054, U4054, BL4054, WPM4054, IT4504, Y1880, PT6102, PT6181, VS6102, CX6001, LC9050 EC49016, CYT5026, Q7051. Before using any of the analogs, check the datasheet.

TP4056

The microcircuit is made in the SOP-8 case (see), has a metal heat collector on its belly that is not connected to the contacts, which makes it possible to remove heat more efficiently. Allows you to charge the battery with a current of up to 1A (the current depends on the current-setting resistor).

The connection diagram requires the very minimum of hinged elements:

The circuit implements the classic charging process - first, charging with a constant current, then with a constant voltage and a falling current. Everything is scientific. If you disassemble the charging step by step, then you can distinguish several stages:

1. Monitoring the voltage of the connected battery (this happens constantly).
2. Precharge stage (if the battery is discharged below 2.9 V). Charge with a current of 1/10 from the programmed resistor R prog (100mA at R prog = 1.2 kOhm) to the level of 2.9 V.
3. Charging with maximum constant current (1000mA at R prog = 1.2 kOhm);
4. When the battery reaches 4.2 V, the voltage on the battery is fixed at this level. A gradual decrease in the charging current begins.
5. When the current reaches 1/10 of the programmed by the R prog resistor (100mA at R prog = 1.2kOhm), the charger is turned off.
6. After the end of charging, the controller continues to monitor the battery voltage (see item 1). The current consumed by the monitoring circuit is 2-3 μA. After the voltage drops to 4.0V, the charging turns on again. And so in a circle.

The charge current (in amperes) is calculated by the formula I = 1200 / R prog... The allowed maximum is 1000 mA.

A real charging test with a 18650 battery at 3400 mAh is shown in the graph:

The advantage of the microcircuit is that the charge current is set by just one resistor. Powerful low-resistance resistors are not required. Plus there is an indicator of the charging process, as well as an indication of the end of charging. When the battery is not connected, the indicator blinks once every few seconds.

The supply voltage of the circuit should be within 4.5 ... 8 volts. The closer to 4.5V, the better (this way the chip heats up less).

The first leg is used to connect the temperature sensor built into the lithium-ion battery (usually this is the middle terminal of the battery cell phone). If the voltage at the output is below 45% or above 80% of the supply voltage, then charging is suspended. If you don't need temperature control, just place that foot on the ground.

Attention! This circuit has one significant drawback: the absence of a battery polarity reversal protection circuit. In this case, the controller is guaranteed to burn out due to exceeding the maximum current. In this case, the supply voltage of the circuit goes directly to the battery, which is very dangerous.

The sign is simple, done in an hour on the knee. If time is running out, you can order ready-made modules. Some manufacturers of ready-made modules add protection against overcurrent and overdischarge (for example, you can choose which board you need - with or without protection, and with which connector).

You can also find ready-made boards with a lead-out contact for the temperature sensor. Or even a charging module with several paralleled TP4056 microcircuits to increase the charging current and with reverse polarity protection (example).

LTC1734

This is also a very simple scheme. The charge current is set by the resistor R prog (for example, if you put a 3 kΩ resistor, the current will be 500 mA).

Microcircuits are usually marked on the case: LTRG (they can often be found in old phones from Samsung).

The transistor will do at all any p-n-p, the main thing is that it is designed for a given charging current.

There is no charge indicator on the indicated diagram, but the LTC1734 says that pin "4" (Prog) has two functions - setting the current and monitoring the end of the battery charge. As an example, a circuit with control of the end of charge using the LT1716 comparator is shown.

The comparator LT1716 in this case can be replaced with a cheap LM358.

TL431 + transistor

Probably, it is difficult to come up with a circuit from more affordable components. The tricky part here is finding the TL431 voltage reference. But they are so widespread that they are found almost everywhere (rarely any power supply can do without this microcircuit).

Well, the TIP41 transistor can be replaced with any other with a suitable collector current. Even the old Soviet KT819, KT805 (or less powerful KT815, KT817) will do.

Setting up the circuit is reduced to setting the output voltage (without battery !!!) using a trimming resistor at 4.2 volts. Resistor R1 sets the maximum charging current.

This circuit fully implements a two-stage process of charging lithium batteries - first, charging with direct current, then the transition to the voltage stabilization phase and a gradual decrease in the current to almost zero. The only drawback is the poor repeatability of the circuit (capricious in tuning and demanding on the components used).

MCP73812

There is another undeservedly neglected microcircuit from Microchip - MCP73812 (see). On its basis, it turns out very a budget option charging (and inexpensive!). The whole body kit is just one resistor!

By the way, the microcircuit is made in a case convenient for soldering - SOT23-5.

The only negative is that it gets very hot and there is no charge indication. It also somehow does not work very reliably if you have a low-power power supply (which gives a voltage drop).

In general, if the charge indication is not important for you, and the current of 500 mA suits you, then the MCP73812 is a very good option.

NCP1835

A fully integrated solution is offered - NCP1835B, providing high stability of the charging voltage (4.2 ± 0.05 V).

Perhaps the only drawback of this microcircuit is its too miniature size (DFN-10 case, size 3x3 mm). Not everyone is able to provide high-quality soldering of such miniature elements.

Of the indisputable advantages, I would like to note the following:

1. The minimum number of body kit parts.
2. The ability to charge a completely discharged battery (precharge with a current of 30mA);
3. Determination of the end of charging.
4. Programmable charging current - up to 1000 mA.
5. Charge and error indication (capable of detecting non-rechargeable batteries and signaling about it).
6. Protection against continuous charge (by changing the capacitance of the capacitor C t, you can set the maximum charge time from 6.6 to 784 minutes).

The cost of the microcircuit is not that cheap, but not so high (~ $ 1) to refuse to use it. If you are friends with a soldering iron, I would recommend opting for this option.

More detailed description is in .

Can a lithium-ion battery be charged without a controller?

Yes, you can. However, this will require tight control over the charging current and voltage.

In general, charging the battery, for example, our 18650 without a charger at all, will not work. All the same, you need to somehow limit the maximum charge current, so at least the most primitive charger is still required.

The simplest charger for any lithium battery is a resistor in series with the battery:

The resistance and power dissipation of the resistor depends on the voltage of the power supply that will be used for charging.

Let's calculate the resistor for a 5 volt power supply as an example. We will charge a 18650 battery with a capacity of 2400 mAh.

So, at the very beginning of charging, the voltage drop across the resistor will be:

U r = 5 - 2.8 = 2.2 Volts

Suppose our 5-volt power supply is rated for a maximum current of 1A. The circuit will consume the largest current at the very beginning of the charge, when the voltage on the battery is minimum and is 2.7-2.8 Volts.

Attention: these calculations do not take into account the possibility that the battery can be very deeply discharged and the voltage on it can be much lower, down to zero.

Thus, the resistance of the resistor required to limit the current at the very beginning of the charge at the level of 1 Ampere should be:

R = U / I = 2.2 / 1 = 2.2 Ohm

Resistor Dissipation Power:

P r = I 2 R = 1 * 1 * 2.2 = 2.2 W

At the very end of the battery charge, when the voltage on it approaches 4.2 V, the charge current will be:

I charge = (U ip - 4.2) / R = (5 - 4.2) / 2.2 = 0.3 A

That is, as we can see, all values ​​do not go beyond the permissible for a given battery: the initial current does not exceed the maximum allowable charge current for a given battery (2.4 A), and the final current exceeds the current at which the battery stops gaining capacity ( 0.24 A).

The main disadvantage of such charging is the need to constantly monitor the voltage on the battery. And manually disconnect the charge as soon as the voltage reaches 4.2 Volts. The fact is that lithium batteries do not tolerate even a short-term overvoltage very badly - the electrode masses begin to degrade quickly, which inevitably leads to a loss of capacity. At the same time, all the prerequisites for overheating and depressurization are created.

If your battery has a built-in protection board, which was discussed a little above, then everything is simplified. When a certain voltage is reached on the battery, the board will automatically disconnect it from the charger. However, this charging method has significant drawbacks, which we talked about in.

The protection built into the battery will not allow it to be recharged under any circumstances. All that remains for you to do is to control the charge current so that it does not exceed the permissible values ​​for this battery (unfortunately, the protection boards do not know how to limit the charge current).

Charging with a laboratory power supply

If you have a current-limited power supply at your disposal, you are saved! Such a power source is already a full-fledged charger that implements the correct charge profile, which we wrote about above (CC / CV).

Everything you need to do for charging li-ion- this is to set 4.2 volts on the power supply and set the desired current limitation. And you can connect the battery.

Initially, when the battery is still discharged, the laboratory power supply will operate in current protection mode (i.e., it will stabilize the output current at a given level). Then, when the voltage on the bank rises to the set 4.2V, the power supply will go into voltage stabilization mode, and the current will begin to drop.

When the current drops to 0.05-0.1C, the battery can be considered fully charged.

As you can see, a laboratory PSU is almost an ideal charger! The only thing that he does not know how to do automatically is to make the decision to fully charge the battery and turn off. But this is a trifle that is not even worth paying attention to.

How do I charge lithium batteries?

And if we are talking about a disposable battery that is not intended for recharging, then the correct (and only correct) answer to this question is NONE.

The fact is that any lithium battery (for example, the widespread CR2032 in the form of a flat tablet) is characterized by the presence of an internal passivation layer that covers the lithium anode. This layer prevents the anode from chemically reacting with the electrolyte. And the supply of external current destroys the above protective layer causing damage to the battery.

By the way, if we talk about a non-rechargeable CR2032 battery, that is, the LIR2032, which is very similar to it, is already a full-fledged battery. It can and should be charged. Only her voltage is not 3, but 3.6V.

How to charge lithium batteries (whether it be a phone battery, 18650 battery or any other li-ion battery) was discussed at the beginning of the article.

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For the normal operation of any battery, you must always remember "Rule of Three Rs":

1. Do not overheat!
2. Do not recharge!
3. Do not overdischarge!

The following formula can be used to calculate the charging time for a NiMH or multi-cell battery:

Charging time (h) = Battery capacity (mAh) / Charger current (mA)

Example:
We have a 2000mAh battery. The charge current in our charger is 500mA. We divide the battery capacity by the charge current and get 2000/500 = 4. This means that at a current of 500 milliamperes, our battery with a capacity of 2000 milliamperes will be charged to full capacity for 4 hours!

And now in more detail about the rules that you need to try to follow for normal operation of a nickel-metal hydride (Ni-MH) battery:

1. Store Ni-MH rechargeable batteries with a small amount of charge (30 - 50% of its nominal capacity).
2. Nickel-metal hydride batteries are more sensitive to heat than nickel-cadmium (Ni-Cd) batteries, so do not overload them. Overloading can adversely affect the current output of the battery (the ability of the battery to hold and deliver stored charge). If you have an intelligent charger with “ Delta Peak”(Interruption of battery charging upon reaching the peak voltage), then you can charge the batteries with practically no risk of overcharging and destruction thereof.
3. Ni-MH (nickel metal hydride) batteries can (but not necessarily!) Be "trained" after purchase. 4-6 charge / discharge cycles for batteries in a high-quality charger allows you to reach the limit of capacity, which was lost during the transportation and storage of batteries in questionable conditions after leaving the assembly line of the manufacturing plant. The number of such cycles can be completely different for batteries from different manufacturers... High-quality batteries reach their capacity limit after 1-2 cycles, and batteries of questionable quality with artificially high capacity cannot reach their limit even after 50-100 charge / discharge cycles.
4. After discharging or charging, try to allow the battery to cool down to room temperature (~ 20 o C). Charging batteries in temperatures below 5 o C or above 50 o C can significantly affect battery life.
5. If you want to discharge a Ni-MH battery, do not discharge it to less than 0.9V for each cell. When the voltage of nickel batteries drops below 0.9V per cell, most chargers with "minimum intelligence" cannot activate the charge mode. If your charger cannot recognize a deeply discharged cell (discharged less than 0.9V), then you should resort to using a more "dumb" charger or connect the battery for a short time to a power source with a current of 100-150mA until the battery voltage reaches 0.9V.
6. If you constantly use the same battery assembly in electronic device in the recharge mode, sometimes it is worth discharging each battery from the assembly to a voltage of 0.9V and making it fully charged in an external charger. Such a complete cycling procedure should be performed once every 5-10 recharging cycles of the batteries.

Charge table for typical Ni-MH batteries

Capacity of elements	Standard size	Standard charging mode	Peak charge current	Maximum discharge current
2000 mAh	AA	200mA ~ 10 hours	2000 mA	10.0A
2100 mAh	AA	200mA ~ 10-11 hours	2000 mA	15.0A
2500 mAh	AA	250mA ~ 10-11 hours	2500 mA	20.0A
2750 mAh	AA	250mA ~ 10-12 hours	2000 mA	10.0A
800 mAh	AAA	100mA ~ 8-9 hours	800 mA	5.0 A
1000 mAh	AAA	100mA ~ 10-12 hours	1000 mA	5.0 A
160 mAh	1/3 AAA	16mA ~ 14-16 hours	160 mA	480 mA
400 mAh	2/3 AAA	50mA ~ 7-8 hours	400 mA	1200 mA
250 mAh	1/3 AA	25mA ~ 14-16 hours	250 mA	750 mA
700 mAh	2/3 AA	100mA ~ 7-8 hours	500 mA	1.0 A
850 mAh	FLAT	100mA ~ 10-11 hours	500 mA	3.0 A
1100 mAh	2/3 A	100mA ~ 12-13 hours	500 mA	3.0 A
1200 mAh	2/3 A	100mA ~ 13-14 hours	500 mA	3.0 A
1300 mAh	2/3 A	100mA ~ 13-14 hours	500 mA	3.0 A
1500 mAh	2/3 A	100mA ~ 16-17 hours	1.0 A	30.0 A
2150 mAh	4/5 A	150mA ~ 14-16 hours	1.5 A	10.0 A
2700 mAh	A	100mA ~ 26-27 hours	1.5 A	10.0 A
4200 mAh	Sub C	420mA ~ 11-13 hours	3.0 A	35.0 A
4500 mAh	Sub C	450mA ~ 11-13 hours	3.0 A	35.0 A
4000 mAh	4/3 A	500mA ~ 9-10 hours	2.0 A	10.0 A
5000 mAh	C	500mA ~ 11-12 hours	3.0 A	20.0 A
10000 mAh	D	600mA ~ 14-16 hours	3.0 A	20.0 A

The data in the table is valid for completely discharged batteries.