Battery capacity meter. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Chargers, batteries, galvanic cells

 Comments on the article

During the operation of batteries, it is recommended to periodically monitor their electrical capacity, measured in ampere-hours (Ah). To determine this parameter, it is necessary to discharge a fully charged battery with a stable current and record the time after which its voltage decreases to a predetermined value. To assess the condition of the battery more fully, it is necessary to know its capacity at various values ​​of the discharge current.

For this, the proposed device is intended. In order to simplify its design, a household electronic-mechanical clock powered by a single 1,5 V galvanic cell was used to count the discharge time (it must be removed before using the clock in the device).

The meter circuit is shown in fig. one.

Fig. 1

On the DA2 chip, a battery discharge current stabilizer and a clock supply voltage stabilizer are assembled.

The discharge current is selected by the SA1 switch. In its first position ("50 mA"), the DA2 stabilizer is loaded with a resistor R6 permanently connected to its output. In the "250 mA" and "500 mA" positions, resistors R7 and R8 are connected in parallel with it, respectively. The HL1 LED indicates the discharge mode, the current through it is stabilized by the field effect transistor VT3.

Parallel voltage regulator DA1 is used as a comparator. Using transistor VT1, he controls a powerful field-effect switching transistor VT2.

Before starting the measurement, an electronic-mechanical clock is connected to the device, the hands of which are pre-set to 12 h 0 min (conditional 0 counting of the discharge time). Then the switch SA1 selects the discharge current, and the variable resistor R4 sets the voltage in the range of 3 ... 12 V, to which the battery should be discharged. After connecting it, press the button SB1 "Start".

Since the voltage of the charged battery is greater than the set value, the voltage at the control input of the stabilizer DA1 will exceed 2,5 V and its output current will increase. As a result, transistor VT1, followed by VT2, will open, and after lowering the SB1 button, the discharge process will continue, as indicated by the HL1 LED.

At the same time, the clock will start counting down the discharge time.

As the battery discharges, the voltage on it decreases, and when it becomes less than the set value, the current through the stabilizer DA1 will decrease sharply, so the transistors VT1, VT2 will close. The discharge will stop, the HL1 LED will go out, the supply voltage to the clock will stop flowing and it will stop. The battery capacity is calculated by multiplying the discharge current by the time recorded by the clock.

All parts of the meter, except for switch SA1, button SB1 and variable resistor R4. mounted on a printed circuit board made of one-sided foil fiberglass, the drawing of which is shown in fig. 2.

Fig. 2

The board is designed to install fixed resistors. P1-4, C2-33, ceramic capacitor K10-17 (C1) and oxide TK series from Jamicon (the rest), TL431CLP microcircuits in the TO-92 package. The terminals of the LM317T (DA2) stabilizer are soldered on the side of the printed conductors, after which it is fixed with a screw and nut on a heat sink with an area of ​​at least 100 cm2 (Fig. 3).

Fig. 3

To avoid short circuits, an insulating gasket made of thin plastic is placed between it and the board, which is glued with epoxy glue to the board and heat sink. The device assembled and tested in operation is placed in a plastic case of suitable dimensions, on the wall of which the SA1 switch (for example, SPl 12-DP3T, SLF-2301-7R), the SB1 button (any small-sized self-returning one, for example, PKN159) and the variable resistor R4 are mounted (SPZ-46M). Opposite the HL1 LED, a hole is drilled in the wall.

Instead of the KT361B transistor, any KT208, KT209, KT361, KT3107 series can be used in the device, instead of KP303B - a transistor of this series with indices A, B and G. We can replace the AL307BM LED with any one with a forward voltage of 1,8 ... 2,5 V and sufficient the brightness of the glow at a current of 2 ... 3 mA.

Establishment begins with measuring the discharge current in various positions of the SA1 switch. To do this, the device is connected through a milliammeter with a measurement limit of 0 ... 5 A to an adjustable power source with an output voltage of about 5 V and a load current of at least 500 mA.

The exact values ​​​​of the discharge current are set by a selection of resistors R6-R8 (starting from the first).

The variable resistor R4 is provided with a scale, which is graduated as follows. By connecting the device and a voltmeter with the appropriate measurement limit to the output of an adjustable power source and moving the slider of the resistor R4 to the lower (according to the diagram) position, turn on the source and set the voltage at its output, to which it is permissible to discharge this battery during operation.

Then they briefly press the SB1 button and, slowly turning the slider, make the HL1 LED go out, after which they make an appropriate mark on the scale, similarly put marks on the scale corresponding to the values ​​​​of the discharge voltage of other batteries.

Author: I. Nechaev, Moscow

See other articles Section Chargers, batteries, galvanic cells.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Machine for thinning flowers in gardens 02.05.2024

In modern agriculture, technological progress is developing aimed at increasing the efficiency of plant care processes. The innovative Florix flower thinning machine was presented in Italy, designed to optimize the harvesting stage. This tool is equipped with mobile arms, allowing it to be easily adapted to the needs of the garden. The operator can adjust the speed of the thin wires by controlling them from the tractor cab using a joystick. This approach significantly increases the efficiency of the flower thinning process, providing the possibility of individual adjustment to the specific conditions of the garden, as well as the variety and type of fruit grown in it. After testing the Florix machine for two years on various types of fruit, the results were very encouraging. Farmers such as Filiberto Montanari, who has used a Florix machine for several years, have reported a significant reduction in the time and labor required to thin flowers. ... >>

Advanced Infrared Microscope 02.05.2024

Microscopes play an important role in scientific research, allowing scientists to delve into structures and processes invisible to the eye. However, various microscopy methods have their limitations, and among them was the limitation of resolution when using the infrared range. But the latest achievements of Japanese researchers from the University of Tokyo open up new prospects for studying the microworld. Scientists from the University of Tokyo have unveiled a new microscope that will revolutionize the capabilities of infrared microscopy. This advanced instrument allows you to see the internal structures of living bacteria with amazing clarity on the nanometer scale. Typically, mid-infrared microscopes are limited by low resolution, but the latest development from Japanese researchers overcomes these limitations. According to scientists, the developed microscope allows creating images with a resolution of up to 120 nanometers, which is 30 times higher than the resolution of traditional microscopes. ... >>

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

Random news from the Archive Plastic that decomposes in soil in six weeks 02.08.2018 A team of scientists from Austria and Switzerland studied the process of biodegradation of PBAT plastic, which is used to make some types of packaging and garbage bags. As a result of the experiment, the researchers found that such material decomposes faster and will allow agricultural companies to reduce the amount of garbage polluting the soil. Agricultural companies often resort to mulching to increase yields. Mulch consists of layers of gravel and plastic sheeting that cover the ground and protect it from overheating or freezing. Often, when cleaning the coating, the film breaks and its pieces remain in the soil, polluting it and reducing fertility. Biodegradation of film particles takes from 700 to 1 thousand years. Scientists have found that film degradation time can be significantly reduced by using PBAT instead of polyethylene. During the experiment, the researchers added PBAT to a glass container with soil, as well as the carbon isotope 13C. Six weeks later, the biologists checked the carbon content and found that the bacteria and filamentous fungi were able to completely destroy the plastic.

Other interesting news:

▪ Smartphones charge faster and understand voice

▪ Photo recognition determines your exact location

▪ comets carrying water

▪ RPS-30/45/65 - compact medical power supplies

▪ Promising material for lithium-ion batteries

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Dosimeters. Selection of articles

▪ article Music plays, standard jumps. Popular expression

▪ article Who Invented the Elevator? Detailed answer

▪ article Guarantees of workers' rights to labor protection

▪ stun gun article. Encyclopedia of radio electronics and electrical engineering

▪ article Arrow indicators. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024