Why is the third contact on the screwdriver battery

Why do you need three contacts on a phone battery?

Some users send us a question about why there are three contacts on the phone battery. There are different opinions on this matter, the emergence of which is facilitated by the lack of documentation on this matter. Confusion is also caused by a large number of phone and battery manufacturers, who often change the assignment of contacts at their discretion. In addition, there are a huge number of counterfeit Chinese batteries and phones. In most of them, the third contact, if present, may not carry any functional load at all..

third, contact, screwdriver, battery

Why do I need three contacts on a phone battery?

In most normal (not “left”) smartphone batteries, the third contact is informational. It serves to transmit data to the phone about the state of the battery. This information contact is halfway between plus and minus. Quality products are usually marked “” and “-“. Therefore, it is sometimes mistakenly referred to as an intermediate conclusion..

Phone battery contact markings

But in lithium batteries of smartphones there is only one bank and there are no intermediate conclusions. In general, through the middle connector, the phone receives information about the serial number of the battery, its nominal capacity, current voltage, and temperature. Other service information may be transmitted depending on the telephone set and the battery..

How is information retrieved? There is very little information on this. The most reasonable explanation for this is the following. The third contact is a thermistor with a certain resistance. By the value of the resistance of this resistor, the phone determines the manufacturer and other information about the battery. To do this, the values ​​of the resistors used are entered into the phone’s firmware..

Naturally, all this works if it is supported at the smartphone and battery level. Therefore, it becomes impossible to talk about such an exchange of information in the case of a counterfeit battery or, conversely, a telephone. And one more detail. On the forums, you can often find recommendations for gluing the third battery contact, in case of problems with charging. This is hardly a good idea. After all, overheating of a lithium battery can lead to very unpleasant consequences..
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Why do I need four contacts on the phone battery?

Nowadays, batteries are often found where 4 contacts are removed..

Temperature controller and sensor

In simplified battery configurations, a 1-Wire module (thermistor and charge controller) is connected to each of the contacts.

Why 3 contacts on the phone battery

Depending on the power scheme, a certain number of connectors are created. Two, three or four. Which on the left and right denote and., Which defines the positive, negative power pin. The third, middle contact is present on the battery as a source of transmission of service information, which includes: state of charge, temperature and other useful data.

A sensor built into the battery is responsible for the temperature. For charge control controller. The sensor monitors the temperature during the charging process. It transmits information about the charge as a percentage, turns it off in case of overcharge or overdischarge. The process allows you to extend the service life, which allows you not to spend money on a new battery. An urgent question for owners who have a non-removable battery.

In “fancy” smartphones, the third contact transmits information about technical characteristics: serial number, information about the phone, about the manufacturer, etc..

third, contact, screwdriver, battery

Important! It is li-ion batteries for mobile devices that are equipped with a third connector, for the reasons described above.

But what if the phone has 4 contacts on the battery instead of 3?

You will find four-pin batteries in almost every laptop, sometimes in tablets or new smartphones..

We just figured out why a device might need a third contact with the 1-Wire protocol, which can perform a fairly large number of tasks. But what are the manufacturers doing with the fourth?

temperature sensor

In almost all phones on the third contact you will find a thermistor for measuring temperature – it provides a simple and safe configuration of the power system.

Battery Upgradation on Bosch GSR ProDrive Profesional ScrewDriver

Data transmission (1-Wire protocol)

In most cases, it is this protocol that is used, which provides communication with low-speed data transfer from 15.4 kbps to 125 kbps.

Data transfer for 3 and 4 pins (I2C protocol)

In new generations of smartphones and portable electronics, manufacturers strive to achieve maximum safety by tying on the third contact as much data as possible to help determine the threat of overheating or failure of the battery cell..

Why does the battery have 3 contacts instead of 2?

Developers of battery-powered gadgets use the third contact differently. It is for this reason that there is no single explanation – there is no unified standard or requirement for certification, for example. What then are the options, you ask?

For this reason, there is no single correct explanation for the presence of a third contact – no one invented the standard, there are no requirements for certification, for example. Everyone is free to do what is most convenient for him.

But there are basic (generally accepted) applications for the third contact. To find out which one is on your phone, you need to disassemble the battery and see the controller diagram.

Branded and patented solutions

There may be various add-ons, like Sony gadgets. But manufacturers don’t talk about their solutions when it comes to technologies that are easy to copy..

If you have a three-pin battery, and the device has four contacts for the battery, then this cannot be the cause of discharge or malfunction. Most likely, during the development of a specific gadget model, in order to save money, the manufacturer unified a single general type of battery for several models (this is often done in Huawei, for example, and Xiaomi).

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Which batteries are best for a screwdriver – an overview and comparison of all types

To find out which batteries are best for a screwdriver, consider their types and characteristics, and also compare with each other. This will help you choose the right battery type that can deliver the power you need and keep your tool powered for a long time..

Lithium-ion (Li-Ion)

One of the new generations of batteries, which first appeared in 1991. Japanese radio engineering companies began to actively use them, and subsequently they managed to increase their power and use them with power tools.

This type is used in mobile phones, laptops and electric vehicles. Their cathode and anode are made of aluminum and copper foil, between which a perforated separator is installed. A valve may be present to release internal pressure.

Response to tool operation at full power

When you need to drill a hole in a dense material or screw a thick and long self-tapping screw, you have to use the tool at full power. In this case, active consumption of charge begins, and the ability to complete the process qualitatively without a drawdown of revolutions depends on the battery’s reaction to this phenomenon..

In view of this, modern Li-Ion batteries are significantly inferior to earlier counterparts. The most powerful in this regard are NiCd and NiMh. When maximum energy output is required, then they are chosen.

What batteries can be used for screwdrivers

Power tool manufacturers always indicate in the characteristics of screwdrivers which batteries are recommended for working with them. The battery type is spelled out in several English letters. To know which battery to choose a screwdriver with, you need to understand the decoding of the abbreviation and know the advantages and disadvantages of each type of battery.

For cordless models, the power and rotation speed of the screwdriver depends on the battery voltage, which must correspond to the parameters of the tool:

  • For screwdrivers, the maximum indicator is 36 V. These are the most powerful devices for working with metal and hard wood..
  • 12-18 V – average value, suitable for most processes in repair and installation.
  • 3-10 V – refer to low-power, and are used only for assembling soft materials or small diameter fasteners.

Installing a battery with a higher capacity on a weaker model will sooner damage the latter. A 12 V battery on an 18 V device will, on the contrary, limit the power of the tool, so the voltage indicator of the drive must exactly match the value on the screwdriver.

Keep in mind that if you take two batteries with the same capacity, the longer operation of the tool will be provided by the one with the higher voltage..

Comparison of batteries used for screwdrivers

Having briefly considered the types of batteries, let’s compare them with each other in ten parameters, which will help to figure out which batteries are better for screwdrivers. We will warn you right away that there is no absolute leader in all categories, and you need to pay attention to those advantages that are useful for a specific activity and scope of use..

Why 3 contacts on the phone battery

Depending on the power scheme, a certain number of connectors are created. Two, three or four. Which on the left and right denote and., Which defines the positive, negative power pin. The third, middle contact is present on the battery as a source of transmission of service information, which includes: state of charge, temperature and other useful data.

A sensor built into the battery is responsible for the temperature. For charge control controller. The sensor monitors the temperature during the charging process.

It transmits information about the charge as a percentage, turns it off in case of overcharge or overdischarge. The process allows you to extend the service life, which allows you not to spend money on a new battery. An urgent question for owners who have a non-removable battery.

In “fancy” smartphones, the third contact transmits information about technical characteristics: serial number, information about the phone, about the manufacturer, etc..

Important! It is li-ion batteries for mobile devices that are equipped with a third connector, for the reasons described above.

Why do I need three contacts on a phone battery?

In most normal (not “left”) smartphone batteries, the third contact is informational. It serves to transmit data to the phone about the state of the battery. This information contact is halfway between plus and minus. Quality products are usually marked “” and “-“. Therefore, it is sometimes mistakenly referred to as an intermediate conclusion..

Phone battery contact markings

But in lithium batteries of smartphones there is only one bank and there are no intermediate conclusions. In general, through the middle connector, the phone receives information about the serial number of the battery, its nominal capacity, current voltage, and temperature. Other service information may be transmitted depending on the telephone set and the battery..

Ремонт аккумулятора шуруповерта. Screwdriver battery repair

How is information retrieved? There is very little information on this. The most reasonable explanation for this is the following. The third contact is a thermistor with a certain resistance. By the value of the resistance of this resistor, the phone determines the manufacturer and other information about the battery. To do this, the values ​​of the resistors used are entered into the phone’s firmware..

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Naturally, all this works if it is supported at the smartphone and battery level. Therefore, it becomes impossible to talk about such an exchange of information in the case of a counterfeit battery or, conversely, a telephone. And one more detail. On the forums, you can often find recommendations for gluing the third battery contact, in case of problems with charging. This is hardly a good idea. After all, overheating of a lithium battery can lead to very unpleasant consequences..
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Why 4 contacts on the phone battery

If on three-contact batteries the third (middle) output is responsible for controlling the temperature, overcharging, transmission of service information, then the fourth output, possibly, takes over part of the functions of the third contact, as on similar phones.

Important! In this case, it is impossible to answer exactly what the third connector is responsible for, and what the fourth is responsible for. Charger manufacturers do not advertise this issue..

On mobile devices 4, the contact can act as a protection when it is not inserted into the “native” device. The charging process will not take place, because the information transmitted through this contact will not correspond to that used in the “real” device.

For example, you have a Samsung phone. And you cannot find a battery of the same brand for it. Look for an analog that works. Perhaps it has a similar battery layout, like a licensed brand battery.

After reading the article, it becomes clear that the third and fourth contacts on the battery of a mobile device play an important role. Helps prevent overcharge and overdischarge. Flushes information to the processor. Extends the operating time of the phone, which is important in everyday life, when it is already uncomfortable to go out without a smartphone.

The performance depends entirely on the charge, so it is so important to know what all the connectors on the battery are used for. Useful when you need to deal with charging another device.

Do you have any questions about the contacts on the phone battery or do you have something to add? Then write us about it in the comments, this will make the material more useful, complete and accurate..

Why does a battery on digital technology need 3 contacts, if it can be charged from two?

The third contact is used for data transmission via the 1-Wire protocol (on batteries with 4 or more contacts, for example, in laptops, the i2c protocol is used).
The battery has a built-in temperature sensor and a charge control controller, which reports the charge in percent and is able to turn off the battery in case of overdischarge or overcharge. There are also more stupid batteries, where the third pin is connected to a thermistor and serves only to measure temperature..
The battery can also be charged with cooler functionality. In Sony cameras, the battery controlled the display backlight, in the PSP, the battery controlled the service mode for starting the set-top box, in the last revision even AES encryption and key exchange were put in there. Yes, all this is on the third contact.

And what happens to the battery when it is charged to the maximum and is left to charge further, plugged into the network? The charger has some kind of safety mode after the battery is fully charged?

the lithium battery is charged according to the CC-CV (Constant Current – Constant Voltage) scheme. At the initial stage of charging, the charger makes sure that the charging current does not go beyond the permissible limits (usually about 1C, that is, approximately equal to the battery capacity in mAh). As soon as the battery voltage approaches the maximum allowable (4.2 V for conventional, sometimes 4.35 V for high-capacity batteries, 3.6 V for high-current LiFePO4), charging limits the current so that the voltage does not exceed this bar. That is, the charging itself makes sure that an overcharge never happens. It can be compared to filling a bucket first with a fast flow of water, as far as the hose allows, then reducing the flow of water so that the splashing water does not overflow, at the end it is carefully added drop by drop to completely fill and not spill.

And the charging speed of the battery depends on the diameter of the wires in the charging transformer?
There is also a ratio of 230 on the primary and 6 on the secondary?

Some users send us a question about why there are three contacts on the phone battery. There are different opinions on this matter, the emergence of which is facilitated by the lack of documentation on this matter. Confusion is also caused by a large number of phone and battery manufacturers, who often change the assignment of contacts at their discretion. In addition, there are a huge number of counterfeit Chinese batteries and phones. In most of them, the third contact, if present, may not carry any functional load at all..

Why does the phone battery have 3 contacts

All rechargeable batteries used in mobile devices have contacts on the edge. With the help of them, the charging process is performed.

third, contact, screwdriver, battery

The article deals with the questions: what each of the contacts is responsible for and how the power supply of three-pin batteries differs from four-pin batteries. It is considered what function they perform, how they help to function better.

Why do I need four contacts on the phone battery?

Nowadays, batteries are often found where 4 contacts are removed..

Four contacts on the phone battery

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Here, again, data on them are scarce. But, most likely, in addition to “” and “-“, one contact transmits information about the charge level, and the second is a thermistor.

Checking by resistance value

The normal functioning of each battery can be verified by comparing the internal resistance of the “banks”. The value is determined by dividing the operating parameters voltage by current and deducting the load resistance.

The operating voltage is measured without fail under load. As a load, you should take a resistor with a resistance of 10 ohms and a power of 25 watts. Each battery is tested. Measure the working amperage and voltage.

For a better understanding, here are some approximate calculations. Let’s say, during the measurement under load, data were obtained for one “can”: operating voltage – 1.19 V and operating current – 112 mA. Before making the calculation, do not forget to convert the current value from mA to A – 0.112 A. We perform the appropriate actions (1.19 / 0.112) – 10 = 0.63 Ohm. Recall that the subtracted in our expression is the load resistance of the resistor (10 Ohm).

Checking the Drive Batteries

So, let it turn out that with the help of preliminary checks, the presence of faulty elements in the drive was established. Then it is necessary to disassemble the battery and remove the batteries connected in series – “banks”. As mentioned above, the battery consists of 10-12 such cells with a voltage of 1.2 V.

First, a visual inspection of the joints of the elements is carried out for violations. They can degrade the overall battery performance..

After inspection, you should measure the voltage of each of the “cans”. The voltage of one cell should not be less than 1.2 V. During measurements, the battery cells should be disconnected from the connections with any kind of sensors. The measuring device is connected to the battery poles. Reduced voltage “banks” must be replaced. If during a simple measurement no faulty elements were found, you should try on the “banks” under load.

Shorted the battery bank

Modern batteries can last up to 10 years before they need to be replaced. Unfortunately, even such elements cannot be completely protected from premature failure, especially as a result of sulfation of plates or closure of cans. The latter problem is especially relevant if the battery was operated in difficult conditions..

Inspection tools

The electrical storage can be checked using:

  • DC voltmeter 15 V;
  • ammeter and DC voltmeter;
  • tester;
  • multimeter.

From the tools you should acquire:

  • pliers;
  • a screwdriver;
  • with a knife;
  • soldering iron.

Checking other parameters

Each type of battery has a certain self-discharge rate.

So, within a month of storage:

  • Nickel-cadmium battery can be discharged by 20%;
  • nickel metal hydride – 30%;
  • lithium-ion storage – up to 8%.

Self-discharge is monitored by measuring the voltage every day for a month.

Checking the power supply elements for the presence of the “memory effect” is carried out by fully charging the battery and completely discharging it. Several charge-discharge cycles (3 or 4) are performed. The battery can be discharged using a 12V lamp. During the operation, the residual operating voltage and the open circuit voltage are measured. After repeated cycles, the “memory effect” will disappear.

Should I try to repair the battery

In old batteries, this is an “age-related disease”. In this case, the most correct solution would be to scrap the battery and purchase a new one. In the event that the malfunction is caused by a crumbling active substance, the battery can be restored.

If the body is made of light plastic, then it is easy to notice an accumulation of dark mass in the lower part of the closed jar, which should be removed. Efforts are justified to restore the battery by washing the can from debris only if the remaining battery cells are in full working order.

Important! If the bank is closed, then it is better not to restore the battery and purchase a new one, since it will still not work to return the former capacity, starting current and voltage.

How to check for a short circuit

The easiest way to check for a short circuit is a serviced or low-maintenance battery. To do this, just unscrew all the covers and put the battery on charge. At some point, serviceable cans will begin to boil, while in a closed one nothing will happen at all. By the way, under load, on the contrary, it is a closed bank that will boil..

If, after that, the density of the electrolyte is measured in each jar, it turns out that in serviceable there will be a normal value (

1.27), and in the dead, the float will rise to the lowest value (slightly more than one). In addition, when starting the engine, a voltage drop of up to 9 volts will appear.

Note! Indirect evidence will be white bloom, which can be observed in the cans through the holes, this is sulfation.

In maintenance-free batteries, there is no open access to the banks, so it will be a little more difficult to determine the short circuit. The easiest way to determine is by a voltage drop of up to 9 volts at the start of the engine. This will not be enough to start and the engine simply will not start. When charging, the battery voltage will not rise above 10.7 Volts.