How to judge the remaining capacity of the mobile phone battery

First, use the voltmeter plus load to detect the battery storage capacity

Detecting the battery storage capacity, it is difficult to be accurate only by using the voltmeter or the multimeter's voltage block without load to check whether the storage of the battery is sufficient. When measuring voltage alone, the current consumption is extremely small, so there is no large voltage drop inside the battery, so the display voltage is not low, but if a considerable load is added, such as turning on the headlight (load current 10 to 15A), press The horn (load current 6 ~ 12A), the battery will make the light dim, the horn is hoarse, thus showing insufficient power storage.

The correct and reliable detection method is to turn on the starter to detect the battery voltage in the car. The steps are as follows: at the normal temperature of the engine, connect a voltmeter to the positive and negative poles of the battery, and pull out the injector wire to make the engine unable to launch. Start the engine for 5 to 10 seconds continuously, and observe the degree of the voltmeter. When the starter and the line are well connected, the battery voltage of 12V is 9.6V or higher than 9.6V, indicating that the battery technology is in good condition; if the voltage is low at the above values, the battery is in a depleted state and the amount of stored electricity is insufficient.

Second, use the hydrometer to detect the battery storage capacity

It is also a common method to use a hydrometer to detect the storage capacity of a battery. Generally, the standard weight of the electrolyte at 20 ° C is 1.25 ~ 1.29 kg / l; if the battery at 20 ° C when the specific gravity of the electrolyte is less than the above value, greater than 1.06 kg / l battery storage capacity is insufficient, need to be charged; When the battery has a specific gravity of 1.06 kg/l or less at 20 ° C, the battery has been completely discharged or damaged. According to this principle, the specific gravity of the battery electrolyte can be measured by a hydrometer to know the storage capacity of the battery, and the condition of the battery can be further determined.

Third, use the battery tester to detect the battery storage capacity

In the daily maintenance and repair, it is really necessary to quickly and accurately detect the amount of battery storage, or use a battery tester. When using the battery detector to the battery for 10 to 15 seconds, the voltage is maintained at 10.5 ~ 11.6V, indicating that the capacity is sufficient, the battery is not faulty; the voltage is maintained at 9.6V ~ 10.5V, indicating that the capacity is insufficient, the battery is not faulty; the voltage drops to Below 9.6V, it indicates that the capacity is seriously insufficient or the battery is faulty. The above is just a simple battery tester, which can only measure the battery voltage under the condition of large current discharge, and roughly judge the storage capacity of the battery. In addition to the start-up discharge, the more advanced battery tester can accurately measure the cold start current (CCA).

Fourth, the conclusion

In summary, the capacity detection methods of the automobile battery include: a voltage gauge or a multimeter's voltage block plus load detection, a hydrometer detection capacity method, and a dedicated battery detector detection capacity method.

Battery capacity is now typically calculated using a 10 hour discharge rate. The discharge current is set to I10 (10% of the nominal capacity), the discharge termination voltage is set to 90% U (90% of the nominal voltage), and the discharge starts. If the battery does not reach the termination voltage after 10 hours, the battery capacity is 100. %, if it reaches 5 hours, it will reach the termination voltage, indicating that the capacity is only 50%, and so on!

[Battery Introduction]

A device that converts chemical energy into electrical energy is called a chemical battery, and is generally referred to as a battery. After discharge, the internal active material can be regenerated by charging - storing electrical energy as chemical energy; and converting the chemical energy into electrical energy when discharging is required. Such a battery is called a battery (storage battery), which is also called a secondary battery. The so-called battery is an electrical chemical device that stores chemical energy and discharges electric energy when necessary.

The nominal capacity of the battery is ampere (AH), where the (A) discharge current and the time (H) is the discharge time. Therefore, accurate measurement of battery capacity is the product of discharge current and discharge time.

The required materials are: battery, ammeter, voltmeter, high-power discharge resistor (loading appliance), switch, stop watch.

First fully charge the battery to be measured to ensure that the capacity is optimal.

Pass the battery through the switch series ammeter, high power discharge resistor, and connect the voltmeter across the resistor. The regulation resistor is used to control the discharge current. (Note that no discharge resistor can be replaced by a load device).

Make a record at the beginning of the measurement. Close the switch and press the stopwatch at the same time. Record the reading of the voltmeter and ammeter. Observe the readings of the voltmeter and the ammeter. When the readings of the two meters start to decrease, stop the stopwatch and record the time.

The current value for calculating the battery capacity is ampere, the time is hour, and multiplying the recorded current by the time is the capacity of the battery.

First, the definition of the battery capacity is defined: a fully charged battery is discharged according to a predetermined constant current, and the time taken when discharging to a predetermined voltage is multiplied by the current to obtain the capacity of the battery.

For example, a lithium battery takes 65 minutes to discharge from full charge (4.2V) at 600mA to 2.75V. The capacity of the battery is 600mA*(65/60)h=650mAh.

How to judge the remaining capacity of the mobile phone battery

When a battery is discharged, the voltage of the battery will gradually decrease as the battery power is lost. In this way, a relatively simple and effective correspondence can be obtained, that is, voltage versus capacity.

Obtain a discharge curve of a normal battery (such as 50mA discharge), and divide the time into 4 equal parts. Take a lithium battery with a charge limit voltage of 4.2V as an example, and you can list such a correspondence.

4.20V----100%

3.95V----75%

3.85V----50%

3.73V----25%

3.50V----5% (because the mobile phone cannot completely use the power of the battery, it may automatically shut down when it is lower than 3.50V)

2.75V----0%

In the hidden menu of many mobile phones, you can call up the engineering mode to check the battery voltage. Of course, the above correspondence varies depending on the type of battery and different manufacturers, but it is similar and can be used for reference. With such a correspondence, the power display of the mobile phone is relatively simple. The single chip samples the voltage value of a battery. For example, if the voltage is 3.90V, it displays 3 grids (4 grids are full), and so on.

How to judge the remaining capacity of the mobile phone battery

How to judge the remaining capacity of the mobile phone battery

If the mobile phone wants to display the precise capacity of the battery, it must always perform the integration of the discharge current and the time. This process is complicated and requires a dedicated chip to complete. One battery has one chip (the cost goes up), and the lithium battery of the notebook power is There are such management chips to accurately obtain the capacity of the battery, and lithium-ion batteries such as smart lithium batteries have similar chips. As far as I know, Texas Instruments' BQ26231 can achieve this function, so their user interface has a percentage of battery capacity. Display, more comfortable, otherwise we can only see the rough "grid" of electricity.

The capacity display of some models (such as 936, S1200, 8288 including the old 818, 838 and other old fighters) is somewhat unconventional. Take the S1200 as an example. His capacity grid is defined as follows:

4.20V~3.76V----4

3.76V~3.72V----3

3.72V~3.70V----2

3.70V~3.60V----1 grid

3.60V below ------0 grid, battery alarm

3.40V self-shutdown

Compared with the normal capacity relationship, when the remaining 3 grids are displayed, it is 3.76V, the actual battery is only about 30% of the power, which explains why the S1200 mobile phone (the above mentioned mobile phones are the same) The first grid can be used for a long time, while the next 3 grids are finished in one day.

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