What voltage should be on the phone battery. The main rules for charging a phone battery. What are lithium batteries
How to Extend Battery Life? Why does my smartphone drain so quickly? We will check the popular myths that you can find on the Internet and tell you the whole truth about modern gadgets.
Myth: Charging at night will shorten battery life.
Should I charge my phone at night? Let's figure it out.
- At the heart of this myth is the danger of overcharging the battery. But this problem is not relevant for modern smartphones.
- Even old lithium-ion batteries rarely overheat if they are connected to a charger for too long. Modern batteries, however, are smart enough to withstand an overnight charge.
- Unfortunately, there is some truth to this myth: the battery does lose its charging capacity if you leave it. But these losses are so minimal that you will not notice them.
- Hence, you don't need to worry if you want to put your smartphone on charge overnight. The consequences will be far from what the owners of phones with old batteries feared.
Tip: The battery will last longer if it is constantly balanced in the 40 to 80 percent range.
Myth: Closing apps will increase battery life.
Many smartphone owners believe that they can extend the battery life of their gadgets by closing the unused ones. But this is a myth, because modern mobile phones are designed for multitasking.
- For example, if you exit an app on iOS, it will be frozen. This means that the program will stop doing anything and will not consume energy.
- By completely shutting down the application, you delete its data from the gadget's RAM. When you decide to open it again, the application will have to reload into the smartphone's memory. This process will require much more battery life than reopening.
Tip: Do not quit the application if you will be using it again soon.
- Instead of constantly closing apps, you can extend the battery life of your gadgets in other ways. For example, background software updates.
Myth: Use Only Original Chargers
Logically, most manufacturers want you to only use original chargers. Native accessories are quite expensive, but it's a myth that they are better for the battery. Other chargers can be used for many gadgets, and we'll show you why.
- Modern devices for charging smartphones are standardized. As a rule, the make-up time from a “non-native” device is slightly longer, but this does not affect the operation of the battery.
- You can charge your smartphone with almost anyone, but we do not recommend using only cheap accessories purchased from well-known Chinese sites.
- Third party chargers are a budget alternative that you can safely use as long as they are certified and charge your battery to the level you need.
Myth: Bluetooth, Wi-Fi, and location services drain your battery faster.
Some applications drain the smartphone battery very quickly. But that doesn't apply to features like Bluetooth, Wi-Fi and location.
- Bluetooth and Wi-Fi don't drain your battery as quickly as many think. When we tested smartphones, the activity of these functions reduced the overall battery life of the gadget by only 30 minutes on average. Agree, these are insignificant losses if the smartphone works for 24 hours.
- But in the past, everything was different: and Bluetooth used other modules, which required much more power to operate than modern counterparts. Progress does not stand still, and now these services do not consume as much energy.
- Turning off location tracking will not increase the overall battery life. But if you are not using this feature, it is best to disable it.
Tip: Most of the energy is spent on the display backlight. Turn off the screen when you are not using a smartphone. Dimming the display can save a lot of battery power.
Myth: Always completely discharge your battery before charging.
Many people think that the battery should always be completely discharged before connecting it to the mains. But we are ready to dispel this myth too.
- This rule was relevant in the days of nickel-cadmium or nickel-metal hydride. It was they who had the so-called "memory effect", in which the total capacity of the battery decreases, and it does not charge above a certain level.
- Today only lithium-ion or lithium-polymer batteries are installed in smartphones, which no longer have a "memory effect". However, some manufacturers still recommend calibrating the battery if the gadget starts to discharge quickly or turns off completely at a certain level of battery charge.
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 diagrams, 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, which contain electrodes and electrode mass.
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 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 | FROM | |
| 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 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 impulse charging.
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 battery capacity).
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 to go 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 operation is its complete disconnection from the battery after charging. This is due to the fact that for lithium batteries it is extremely undesirable for them to stay 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 stay means tens of hours or more.
During the second stage of charging, the battery manages to gain 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 with a constant current of a reduced value until the voltage on the battery reaches 2.8 V.
A preliminary stage is necessary to prevent swelling and depressurization (or even explosion with fire) of damaged batteries, for example, 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 precharge 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 control 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 is the 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 an 18650 battery 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 \u003d 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?
All lithium batteries charge the same way. It doesn't matter if it's 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 forbidden to use lithium batteries in household appliances unless they have a built-in protection board. Therefore, all batteries from cell phones always have a PCB board. 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 were supplied with 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 \u200b\u200bthe 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 protected battery easily turns 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 charging 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 the charging current and the 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 the 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 a penny in general (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 LM350 instead of LM317. True, it will be more expensive - 11 rubles / piece.
The printed circuit board and assembly are shown below: 
The old Soviet transistor KT361 can be replaced with a similar p-n-p 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 charging current is typically 280mA.
The microcircuits have built-in overheating protection. Even so, the circuit continues to operate, decreasing the charge current by 17 mA for every degree above 110 ° C.
There is a precharge 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 under no circumstances can 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. In general, 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 circuit output.
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 charger produces a fairly low charging current, so 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 wiring diagram is taken from: 
An important advantage of the circuit is the absence of low-resistance power resistors limiting 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 kΩ.
The charging assembly looks like this: 
The microcircuit heats up quite well during operation, but this does not seem to interfere with it. Performs its function.
Here is another PCB option with smd LED and micro USB connector: 
LTC4054 (STC4054)
A very simple circuit, a 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 \u003d 1000 / R... You should not set 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 "earthy" 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 for the LTC4054 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 allows for more efficient heat dissipation. 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 constant current, then with constant voltage and falling current. Everything is scientific. If you disassemble the charging step by step, then you can distinguish several stages:
- Monitoring the voltage of the connected battery (this happens constantly).
- Pre-charge 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 \u003d 1.2 kOhm) to the level of 2.9 V.
- Charging with maximum constant current (1000mA at R prog \u003d 1.2 kOhm);
- 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.
- When the current reaches 1/10 of that programmed by the R prog resistor (100mA at R prog \u003d 1.2kOhm), the charger turns off.
- 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 \u003d 1200 / R prog... The allowed maximum is 1000 mA.
The 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 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 the middle lead of a cell phone battery). 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 seal 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 chips to increase the charging current and with reverse polarity protection (example).
LTC1734
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 in general 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. For example, a circuit is shown with control of the end of charge using the comparator LT1716. 
The comparator LT1716 in this case can be replaced with a cheap LM358.
TL431 + transistor
Probably, it is difficult to come up with 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 does any power supply 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 transition to the voltage stabilization phase and a smooth 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, a very budgetary charging option (and inexpensive!) Is obtained. 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 can provide high-quality soldering of such miniature elements. 
Of the indisputable advantages, I would like to note the following:
- The minimum number of body kit parts.
- The ability to charge a fully discharged battery (precharge with a current of 30mA);
- Determination of the end of charging.
- Programmable charging current - up to 1000 mA.
- Charge and error indication (capable of detecting non-rechargeable batteries and signaling about it).
- 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 also not so high (~ $ 1) to refuse to use it. If you are friends with a soldering iron, I would recommend opting for this option.
A 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 a 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, but 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 \u003d 5 - 2.8 \u003d 2.2 Volts
Suppose our 5V 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 probability 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 \u003d U / I \u003d 2.2 / 1 \u003d 2.2 Ohm
Resistor Dissipation Power:
P r \u003d I 2 R \u003d 1 * 1 * 2.2 \u003d 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 \u003d (U ip - 4.2) / R \u003d (5 - 4.2) / 2.2 \u003d 0.3 A
That is, as we can see, all the values \u200b\u200bdo 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 very poorly tolerate even a short-term overvoltage - 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. Upon reaching a certain voltage on the battery, the board will disconnect it from the charger by itself. 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 \u200b\u200bfor the given battery (unfortunately, protection boards do not know how to limit the charge current).
Charging with a laboratory power supply
If you have a power supply with current limiting protection, then 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).
All you need to do to charge the li-ion is to set 4.2 volts on the power supply and set the desired current limit. 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 switch to 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 to be recharged, 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 passivating 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, leading to 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 (be it a phone battery, 18650 battery or any other li-ion battery) was discussed at the beginning of the article.
The owners of modern mobile phones are constantly faced with such a problem - the battery ceases to hold a charge. Therefore, the phone question? "Is quite logical, because you almost never want to buy a new battery.
Why the battery does not hold a charge well
Battery capacity drops over time, a physical process that cannot be prevented. The battery has its own shelf life, and when it comes to an end, the properties of the battery begin to deteriorate. However, the answer to the question "Is it possible to reanimate the battery for the phone?" remains positive - it is quite possible to extend its service life, and below we will tell you how.
In addition, the battery may be less able to hold a charge due to a physical problem - dirty contacts or swelling. Here, most likely, you will need to replace it.
Why the phone won't charge
The battery does not charge usually due to some kind of physical malfunction. Can you reanimate your phone battery in such a situation? No, most likely it is not possible, since a breakdown will not allow doing this. However, it so happens that the battery cannot be charged if it has been completely discharged long ago, that is, a deep discharge has occurred. And in this case, the phone battery can still be helped.
after deep discharge with a battery
If it has not been fully charged for a long time, then it may well not respond to normal charging. In this case, you can try charging it with another battery. For this procedure you will need:
- Nine volt battery.
- Ten centimeters of duct tape.
- Two conventional thin electrical wires.
- Directly "killed" battery.
- Wrap electrical tape around the wires, leaving free edges on both sides.
- Connect one wire with one end to the positive terminal and the other to the negative terminal. You can understand the contacts by marking. Be sure to use two different wires.
- Tape the wires with electrical tape.
- Connect the other ends of the wires to the plus and minus of the battery, respectively. Be sure to connect the battery plus to the battery plus, and the battery minus to the battery minus! Failure to do so could result in a short circuit, resulting in electric shock and damage to both power supplies.
- Tape the wires to the battery with electrical tape.
After these manipulations, wait until the phone's battery heats up a little. This usually takes about a minute. Then let the battery cool down and place it in the phone. If the phone turns on, then congratulations - you've just learned how to reanimate your phone's battery!
How to reanimate a phone battery at home with a "frog"
Another fairly simple way to restore the battery is to charge it with the "frog" device. This device allows you to quickly charge even a completely discharged battery. It is a block that plugs into an outlet. The battery is connected to it, then the "frog" contacts are connected to the "patient" contacts and charging begins. As a rule, it does not take much time. This method helps many, although it is not always effective.
Freezing the battery
Many of us have heard the question "How to reanimate the phone battery in the freezer?" This seems like a strange question, but it's actually a very effective method. It is carried out in several stages:
- Remove the fully discharged battery from the phone.
- Place it in a bag. It must be plastic and sealed so that water does not get on the battery.
- Place the battery pack in the freezer for about 12 hours.
- Better to put something under the bag to keep it from freezing to the bottom of the freezer.
- After 12 hours, remove the battery and let it warm up to room temperature. Never insert a cold battery into your phone!
- Wipe the battery off moisture, insert it into the phone and turn on the mobile.
- If the phone turns on, then put it on charge.
The low temperature restores the battery's energy slightly and allows it to be charged efficiently with conventional chargers. By the way, sometimes it helps even if the battery just became worse to hold a charge.
Important warnings
- Never leave the battery connected to a 9-volt battery for long periods of time, as it may explode.
- Sometimes if you leave them in the freezer for a long time. This is due to the fact that too long exposure to low temperatures is no less destructive for the battery.
- If you think the battery is defective, check first to see if there is a problem with the charger. Perhaps the phone is not charging due to the fact that it was it that broke.
- Try to charge only fully discharged batteries with a 9V battery. If the battery works, it can easily catch fire or explode altogether.
- Be sure to place the battery in the freezer in an airtight bag so it won't spoil your food if it suddenly leaks.
If you follow these tips, then the question of how to reanimate the phone battery will be solved for you quickly and without problems.
How to restore the previous battery capacity
If your battery has not "died", but simply became worse to hold a charge, then at home, with the help of a few manipulations, you can return its capacity for a while. To do this, you will need this part, a power supply with voltage regulation, a rheostat and a voltmeter.
- Connect a rheostat and a voltmeter in parallel to the battery.
- Reduce the voltage to one volt, but not below 0.9 volts.
- Make sure the battery is not hotter than 50 ° C. If it gets hotter, turn it off and cool to room temperature.
- Wait about 15 minutes.
- Connect battery and ammeter in series and voltmeter and current source in parallel. Connect one contact of the voltmeter with the free pole of the battery, and the other with the contact of the ammeter.
- After that, slowly attach the temperature sensor to the battery and set the minimum voltage with the regulator.
- Then lift it up carefully until the amperage is equal to one tenth of the battery capacity.
- Raise the voltage level every five minutes, and when the amperage begins to decrease, do it every hour.
- When the voltage reaches 1.5 volts, just leave the battery charging.
- After 5-6 hours or less, the amperage will drop to zero. Disconnect charging at this point.
- Wait about half an hour and put the phone on a regular charge.
Sometimes this procedure needs to be repeated several times, but the results can be really impressive.
Now you know how to reanimate your phone battery in various, even the most difficult situations. For some methods, you will need almost nothing, while for others, you will need minimal skills in handling electricity. If you think that you do not have them, then try taking the battery to a service center. Sometimes, not so large sums are taken for its restoration.
If you still cannot restore the battery, then think about buying a new one - anyway, any device has one or another service life, and it is far from always possible to extend it. And batteries, even branded ones, are not that expensive today.
With long-term storage and non-compliance with the charging and discharging modes of operation, cell phone batteries become unusable. An attempt to restore the capacity of batteries with a long charge or special modes of charging and restoring the capacity does not always lead to the desired result. Nickel-cadmium and nickel-metal hydride batteries used in cellular communications, in comparison with lithium-ion batteries, have a "memory effect", do not allow long-term connection to a charger, and require training cycles. Lithium-polymer batteries use a solid dry electrolyte made of polymer, the disadvantage is poor conductivity, the advantage is very small thickness, resistance to overcharge.
The battery after prolonged use does not have sufficient capacity for operation, it quickly discharges and takes a long time to charge.
Aging of batteries is caused by increased crystallization. The crystals have high resistance and reduce the charge-discharge current. The use of impulse chargers with a control system and trickle charging allows to extend the battery life.
It is possible to discharge the battery with currents not exceeding the standby transmission currents of 150-200 mA, loading with large currents - the protection circuit will disconnect the battery from the load in 10-20 ms. after connection, the circuit is locked and the discharge current drops to almost zero, when the discharge circuit is re-closed, the discharge current reappears. This is to prevent the lithium-ion battery from exploding after the formation of lithium metal and the danger of leakage.
The discharge current during battery diagnostics can be obtained in a pulsed mode with a certain pulse repetition rate, the so-called pulse discharge.
To determine the technical condition of a cell phone battery, it is necessary to load it with a pulsed discharge current.
This solution is also applicable for diagnostics of alkaline and acid batteries of any capacity, it all depends on the capacity of the batteries and discharge circuits.
The internal resistance of cell phone batteries should not exceed 0.3 Ohm, a large value will not allow normal operation for a long time, the voltage drops rapidly, and soon the screen goes out with the transition to the energy-saving storage mode. For the recombination of lithium ions in the battery after a full charge, it is recommended to rest the battery for 3 to 5 hours. The shape and time of the discharge pulse of the cell phone battery diagnostic device must repeat the shape of the battery load current in the digital signal transmission mode in the GSM standard - the transmission pulse current is 1.5 Amperes, the duration is 567 μs and the repetition rate is 4.61 ms. The current consumption during pauses is 200mA. The lithium battery protection unit consists of two microcircuits, one operates in the comparator mode, the second contains two series field-effect transistors with built-in diodes turned on in the opposite position with the following functions: protection against over-discharge (when the voltage on the battery during discharge is below the set level, the closing delay of the field-effect transistor VT1 is 12ms), protection against short-circuiting the battery terminals (when the voltage on the field-effect transistors exceeds a certain threshold, the transistor VT1 closes at a speed of 0.4 ms), protection against exceeding the permissible charging current (someone else's charger - VT2 closes), charging highly discharged batteries (cell voltage is more than 1.5 Volts).
The schematic diagram of the device for diagnosing cell phone batteries (Fig. 1) consists of a waiting multivibrator of pulses on an analog timer DA1, with a manual external start and setting the generator frequency, a discharge circuit on a bipolar transistor VT1 and an analog indicator of the capacity of the battery under study on a DA3 microcircuit. The power supply of the circuit diagram is made from the mains source through the DA4 voltage regulator.
In the initial state, at the output 3 of the DA1 timer, the voltage level is close to zero, since at the initial moment of power supply at the input of the lower comparator, the voltage level is higher than 1/3 Un. In this stable state, the circuit can remain for as long as necessary.
When you press the SB1 button - "Start", a trigger pulse appears at input 2 of DA1 in the form of a low voltage level, the lower timer comparator is triggered and the internal trigger switches, which will close the reset transistor at the 7DA1 input, the capacitor C2 will start charging through the resistors R3, R4, during this time, the output of 3DA1 is kept high. Generation of rectangular pulses will continue with time T1 \u003d 1.1 C1 (R1 + R2).
Upon reaching a voltage of 2/3 Un on the capacitor C2, the upper comparator is triggered and zeroes the trigger, the internal reset transistor discharges the capacitor C2 through the resistor R5.
When the voltage across the capacitor C1 reaches more than 1/3 Un, the timer will stop working.
The duration of a single pulse at the 3DA1 output T2 \u003d 1.1C2 (R3 + R4) can be smoothly changed with a variable resistor R4.
Pin 5 of DA1 allows direct access to the divider point with a voltage level of 2/3 Un, which is the reference for the operation of the upper comparator. Using this pin allows you to change this level to obtain circuit modifications. This pin is used in this cell phone battery diagnostic device to stabilize the measurement mode and correct the effect of external temperature. The voltage modification at pin 5DA1 is performed using the DA2 microcircuit - an adjustable parallel voltage regulator and is used as a reference voltage source - an adjustable zener diode. The microcircuit of the stabilizer has its own protection devices against overload and increased input voltage. Thermistor RK1 allows you to correct changes in the technical condition of the battery, taking into account the increase or decrease in the external temperature.
With an increase in the voltage at the load R9 in the emitter circuit of the bipolar transistor VT1, the parallel stabilizer opens at the control input 1DA2, the cathode-anode resistance decreases and the voltage at pin 5 of DA1 drops, the frequency at the output of the 3DA1 timer increases, which leads to a decrease in the voltage at the load R9. The purpose of the transistor VT1 in the diagnostic circuit is to connect the load, the discharge resistor R9 to the GB1 battery. The tested battery is connected to the collector circuit of the transistor; in addition to the load, the voltage and temperature control circuits of the negative feedback circuit RК1, R11, R10 and the battery capacity level control circuit R12, R13, R14 are connected to the emitter circuit.
The voltage of the batteries of different versions is slightly different, the adjustment can be done with the resistor R11. The voltage drop across the load - resistor R9 when the transistor VT1 is opened with the next pulse of the generator, creates a voltage drop, the greater the larger the battery capacity and the lower its internal resistance. From the variable resistor R13 through the resistor R14, the control voltage is supplied to the input amplifier of the five-channel timer DA3. LEDs are connected to the conclusions of the keys of the comparators K1-K5. The increase in voltage at the 8DA3 input, after amplification, goes to the internal signal voltage divider, the keys at the internal comparator inputs will open when this voltage is exceeded. The higher the signal level, the more keys will be opened. When the voltage at the 8DA3 input is 0.25 Volts, all LEDs are on.
LEDs should be distributed in the following order according to their glow: red, full discharge - HL1, orange HL2 - minimum battery capacity, green HL3, HL4 - 50 -75 percent charged, blue HL5 -100%. When fully charged, the ZQ1 siren will sound.
The adjustment of the basic diagram for diagnosing cell phone batteries begins with checking the operation of the generator on the DA1 timer, if there is no oscilloscope, the pulses at the output 3 of the DA1 timer can be determined by the LED or a voltmeter at a high level by pressing the "Start" button.
Having connected a freshly charged cell phone battery in the correct polarity, set the HL5 LED to glow with resistor R13.
When diagnosing batteries with a service life of more than 6 months, the number of LEDs on will decrease. Lowering the voltage across the battery with a high internal resistance will reduce the voltage drop across the discharge resistor R9. The connection of the tested battery to the diagnostic device is carried out with the sharp tips of the control cords used from the testers.
The measurement time is set by the resistor R1, the pulse repetition rate within 400 -1000 Hertz is set by the resistor R4.
The LEDs are mounted in the holes in the front panel of the case in an acceptable order. All radio components are small-sized and mounted on a printed circuit board.
A mains transformer for an output voltage of 2 * 9 volts 100mA is mounted in the case separately from the printed circuit board. The mains supply, in a portable version of using the device, can be replaced with a 9-volt Krona battery.
Literature:
- V.Konovalov "Charger and recovery device for Ni-Ca batteries" Radio №3 / 2006 p.53.
- V.Konovalov "Measuring instrument R-vn AB" Radiomir No. 8.2004. page 14.
- V. Konovalov "Pulse diagnostics of batteries". No. 7.2008 page 15
- D.A. Khrustalev "Accumulators" Moscow 2003
- IP Shelestov "Useful schemes for radio amateurs" book 5.
- Chips for protecting lithium batteries. Radio No. 8 2004, p. 49.
- Small-sized network transformers. Radio No. 8/2004 p.44.
- I. Nechaev "Voltage stabilizers with a microcircuit KR142EN19A." Radio No. 6.2000 p. 57.
List of radioelements
| Designation | A type | Denomination | number | Note | Score | My notebook |
|---|---|---|---|---|---|---|
| DA1 | Programmable timer and oscillator | TLC555M | 1 | Into notepad | ||
| DA2 | Voltage reference IC | TL431 | 1 | Into notepad | ||
| DA3 | Chip | AN6884 | 1 | Into notepad | ||
| DA4 | Linear regulator | LM7809 | 1 | Into notepad | ||
| VT1 | Bipolar transistor | KT829A | 1 | Into notepad | ||
| VD1 | Diode | KD512B | 1 | Into notepad | ||
| VD2 | Diode assembly | F12C20C | 1 | Into notepad | ||
| C1 | 47 uF | 1 | Into notepad | |||
| C2 | Capacitor | 0.1 uF | 1 | Into notepad | ||
| C3 | Capacitor | 0.01 μF | 1 | Into notepad | ||
| C4 | Capacitor | 0.22 | 1 | Into notepad | ||
| C5, C7 | Electrolytic capacitor | 470 uF 16 V | 2 | Into notepad | ||
| C6 | Electrolytic capacitor | 10 μF 16 V | 1 | Into notepad | ||
| R1 | Trimmer resistor | 1 MOhm | 1 | Into notepad | ||
| R2 | Resistor | 100 kΩ | 1 | Into notepad | ||
| R3 | Resistor | 33 k Ohm | 1 | Into notepad | ||
| R4 | Trimmer resistor | 330 k Ohm | 1 | Into notepad | ||
| R5, R10 | Resistor | 510 Ohm | 2 | Into notepad | ||
| R6, R8 | Resistor | 1.5 k Ohm | 2 | Into notepad | ||
| R7 | Resistor | 12 kΩ | 1 | Into notepad | ||
| R9 | Resistor | 3 ohm | 1 | 5 watts | Into notepad | |
| R11 | Variable resistor | 2.2 k Ohm | 1 | Into notepad | ||
| R12, R15 | Resistor | 5.6 k Ohm | 2 |
In modern life, no one is surprised that the Internet can be used anywhere and everywhere, regardless of where a person is. Portable mobile devices in the form of smartphones provide constant communication with the outside world. This is due to the numerous base stations and the presence of a small but rather capacious battery inside our gadgets. However, with intensive use, the battery on the phone sooner or later runs out, and the question arises of how to check the phone's battery so that the battery failure is not taken by surprise.
Checking the phone battery yourself
Test the battery yourself using the simplest method. Make a free call to some number belonging to the service provider of the cellular operator, or just call a friend and stay on for about ten minutes. Then notice the number of bars that show the quality and duration of the battery on the phone display. Ideally, there should be no decrease in the number of divisions for ten minutes. If this happened, then, most likely, it is coming to an end.
Checking the phone battery using special applications
Systems of new and modern models of tablets and smartphones may already be equipped with similar programs. For example, there is such a program on Android. In order to activate it, you need to enter a certain combination of characters: * # * # 4636 # * # *. After typing in the menu, go to the "Battery Information" section, where you can find all the necessary data about the state of the battery and what its performance is at the moment.
There is a BatteryCare app that can be downloaded through the AppStore. It also checks the battery capacity of Androids and smartphones. In addition to it, there is also a good utility Nova Battery Tester, developed specifically for tablets and smartphones, with the option to determine the actual battery capacity. During the development of this program, the battery capacity indicators were checked for a long time in laboratory conditions.
If a similar program is not installed on the mobile phone, or, for some reason, it is impossible to download it,.
Checking the phone battery with a multimeter
As you know, many manufacturers, indicating their capacity on the case of batteries, often exaggerate these indicators. To correctly and to find out how to check the battery of a phone or any other gadget, you should use a mini multimeter or just a tester. Compared to a traditional multimeter that measures the performance of conventional AA batteries or other larger batteries, the tester looks like a small rectangular box with a USB cable. Such a device can be purchased at any online store, in particular, on AliExpress.
At the front end of the tester there is a display that displays all the necessary information:
- voltage;
- current strength;
- battery capacity in smartphone ;
- memory cell (switched by one button on the front side).
The USB cable connected to the multimeter should be connected to a power source (for example, a charger from a gadget or a computer). The tester has two connectors - USB and micro USB.
If you need to know the capacity of a tablet or mobile phone with a micro-USB input, you need to connect the supplied cable to the tester into the USB connector on the tester, and connect the other end of the cable to the phone. Beforehand, you should completely discharge the gadget.
We connect the tester to the charger, the cable to the tester and to the phone. We select a free memory cell on the tester's display, or we erase the old one and wait for the phone to be fully charged. At the end of the process, the charging indicator should be 100%, the current should be at zero, and the real indicator of the battery capacity will be visible.
After a simple check by the tester, the user can always be aware of the level of battery health in his mobile phone. If the capacity is small, and the battery is quickly discharged, do not immediately run to the service department. Before contacting a specialist, you can try to restore the battery capacity on your own using a simple method that is always at hand.
A simple method of restoring battery capacity: "swing"
The phone's battery should be checked regularly because it can lose its capacity level not only due to heavy use of the phone for communication on social networks. Do not forget that during storage the battery capacity also becomes smaller. This may apply to new, unused batteries during the initial purchase of the phone, as well as those that could lie without use for a long time.
In such situations, the so-called process of "swinging" the battery helps, thanks to which you can return its previous level of performance:
- charge the battery of your mobile phone or tablet completely ;
- then discharge it completely ;
- repeat the same three times .
If after the "buildup" the working time of the battery has increased, then it is not yet necessary to purchase a new one, but it is advisable to constantly monitor its performance. It never hurts to master a simple method of "swinging" after a preliminary analysis of the state of the battery. Carrying out the simplest actions with the battery yourself is much better than running to a service center for the first reason, where they can take money for each manipulation with the phone - and sometimes quite a lot.
Thus, any owner of a modern mobile phone can master a number of methods himself. In addition, most of the technical devices at hand can actually be purchased in online stores, they are affordable and easy to use. If the test showed a large loss of battery capacity, and it was not possible to "swing" it either, it is best to immediately replace the old battery with a new one.