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Somehow recently it became necessary to measure the capacity of one battery in a smartphone, as it began to discharge too quickly, and, of course, I wanted to order another trifle on AliExpress. As a result, after spending a couple of minutes searching, we found it on AliExpress, for sure, but there was another promotion on aliexpress and the price turned out to be more profitable. If you wake up to buy, then check for yourself, perhaps at that time the situation will change, but do not forget that, therefore, do not be lazy and calculate for yourself where it will be more profitable for you to make a purchase. But let's not deviate from the topic and return to the actual review of the device itself.
Fortunately, we managed to find a device for measuring battery capacity, which has already sold more than two thousand of these testers, and moreover, customer reviews about the product are only positive. If you look for it yourself, then here's the original name of this tester "" for your reference, perhaps at the time of your purchase a better offer will turn up. At the time of the order, the price of the tester for measuring the battery capacity was $4.26, since we got on some kind of promotion, the regular price was $7.10, but we managed to buy it even cheaper thanks to the cashback service on aliexpress. In the end, we paid $3.90, delivery was indicated, the order was placed, all that remained was to wait.
As a result, after about 20 days, the package arrived. By the way, the track code was without letters, it was ordinary digital and was tracked only until the moment of export from China, after which it was only necessary to wait, since the parcel arrived quickly, but a trifle usually always arrives faster than large parcels, so nothing surprising. The seller packed the device for measuring battery capacity in a standard yellow international envelope, after wrapping it with several layers of pimply film, for which special thanks to him. Everything inside the envelope turned out to be exactly as indicated in the product description. On the reverse side of our device for measuring battery capacity, there is information on both the permissible input and output voltage and the maximum capacity level of the indicator. This information is mainly for fans of experiments who love games with sockets, but since we bought it for simple household needs, like measuring the battery capacity in a smartphone, tablet, camera, we simply took this information into account and decided to check the performance of the tester.
First of all, we connected the tester to, using a USB cable, which is built into the case on one side, and on the other, we inserted a USB cable from the phone. Immediately, all the necessary information appeared on the screen, about voltage, current strength, and a counter started showing the amount of transferred charge, which is measured in mAh ( milliamp hours). Actually, the device for measuring battery capacity already performs its main function and copes with it quite well. But if you look closely, you will notice a small button next to the display. It is needed for comparative measurements, in other words, this memory of 10 cells, in which the indicators of your measurements are saved. This function works according to the following principle - with short presses on the button, you can scroll through the readings of saved measurements, you can activate the viewing of cells with one double press, and reset with one long one. As for us, the function itself is not particularly necessary, but perhaps someone will come in handy.
We tested a device for measuring battery capacity both on smartphones, tablets, and on (Original Xiaomi Power Bank 16000mAh), which we recently ordered from. Of the declared 16000mAh, in an almost new external charger, we managed to count 15874, which is very good. They also connected to, the results were also pleasing, for 3 months of use, the battery capacity decreased by only 2%, however, the original Xiaomi products have not been satisfactory for a long time.
If you want to accurately measure the volume of your battery, we recommend that you connect the battery capacity meter to a completely discharged device, and only then put it on charge.
Of course, you can’t expect super accurate readings from a device for a couple of dollars, but it’s a necessary thing in everyday life, especially for all sorts of geeks who love to do all sorts of experiments. Definitely, the functions of this tester are more than enough to measure the battery capacity in your smartphones and tablets.
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We present a project of a self-made active electronic load. The active load itself is nothing special, but here the base extension is a microcontroller used to measure current, voltage and power and test the capacity of any battery from 100 mAh to 99 Ah with automatic load disconnection from the source after reaching the set discharge voltage. An additional action of the microcontroller is to control the fan speed depending on the heatsink temperature.
The operation of the basic active load circuit is quite simple - a power transistor is connected in series with a source power measurement resistor with a power source (for example, a power supply, a battery). The transistor is controlled by an error signal generated in the instrumentation amplifier based on the voltage signal received from the instrumentation resistor and the voltage signal supplied from the control potentiometer. The difference in these signals causes the transistor to open or close through the measuring amplifier to equalize them. This affects the amount of current flowing through the transistor and hence the current from the source under test. A voltage proportional to the current flowing through it in accordance with Ohm's law is applied to the measuring resistor.
Of course, this basic circuit has many different modifications, such as more than one power transistor, additional control transistors, a MOSFET instead of bipolar transistors, improved versions of operational amplifiers, and so on.
In this project, the simplest version was used with one STW20NB50 field effect transistor in the TO-247 package. The transistor is directly driven by a dual op-amp LM358 powered by a single 9V voltage. The measured voltage from the power resistor (2 parallel 0R1 5W resistors) is fed through a simple RC filter to the inverting input of the first amplifier, and to the non-inverting input of the other op-amp to amplify the voltage. before transfer to the microcontroller - current measurement.
The voltage of the two control potentiometers connected in series is also applied to the input of the non-inverting first amplifier, creating a coarse and fine adjustment system absorbed by the current load. In the first op-amp, an error signal is generated that controls the power transistor. The transistor operates linearly, which is somewhat unusual for a MOSFET, but perfectly normal in this case.
Attention: this active load circuit may not be able to withstand the reverse connection of the power supply under test!
The project is based on the ATtiny26 microcontroller. It is controlled by an internal oscillator with a frequency of 8 MHz, which, during the first few triggers, is calibrated "manually" by trial and error, changing the parameter entered in the OSCCAL generator register at the beginning of the program (correcting several times, compiling and programming). Although the circuit has a function for measuring battery capacity, which consists in calculating the received load as a function of time, we do not consider it necessary to stabilize the time using quartz, since this is not a laboratory equipment, and small deviations in the counted time (after calibrating the generator) have little effect on the battery measurement result . If someone wants to stabilize the timer with quartz, you can do that.
The program was written entirely in assembler and occupies the available processor memory, only 2 KB.
The ADCs are fed through a blocking capacitor at the end of the AVCC and use an internal voltage of 2.56 V as the reference voltage source. Measurements are taken cyclically every 200 ms in the main program cycle.
In order to view the current and voltage with an accuracy of 0.01, the ADC processing accuracy was increased from 10 to 12 bits by software. Without this procedure, the accuracy of the voltage indication in the assumed range of 30 V was 30 V / 1023 (ADC) = ~ 0.03 V, which is not very good.
Thanks to oversampling to 12 bits, the accuracy of the voltage readings was 30 V / 4095 (ADC)<0,01 В. Для тока с предполагаемым диапазоном 10 А избыточная дискретизация была по существу ненужной, потому что 10 А / 1023 (АЦП) = ~ 0,01 А, что достаточно.
With each measurement, many "fast" readings are taken from the ADC, from which the average value is extracted, which then falls into a "free" circular buffer, which is cyclically filled with each measurement. The average value of this buffer is taken only for further correct current or voltage calculations. As a result, the readings are quite stable and respond quickly enough to changes in the measured values.
The temperature of the radiator is measured by the circuit on the Dallas sensor (it can be 18B20 or 18S20 - the program recognizes and adjusts) with an accuracy of the nearest degrees, and on this basis it is determined how quickly to turn the radiator fan - the hotter it is, the faster the rotation. When the power is turned on, the fan starts at high speed and after a while reaches the minimum speed according to the temperature.
The measurement of battery capacity consists mainly of summing up the current readings at given time intervals (here 1 s) and then integrating this sum for intervals of a certain time (here 1 h = 3600 s). For example, let it be the current measurement 1 A; if we sum it up for an hour every second, then we get the sum of the readings \u003d 1 A x 3600 s \u003d 3600 Ac; if we divide it by a constant integration period equal to 3600 s (1 hour), we get 3600 As / 3600 s = 1 A per hour.
Let's check if the current = 4 A for 10 hours, then what happens? 4 A x 36000 s = 144000 Ac -> 144000/3600 = 40 Ah.
To measure the capacity of a battery, it must be connected to a load with the minimum coarse and fine potentiometers (load shedding) and with the maximum cutoff voltage adjustment potentiometer. The display should show battery voltage, eg 12.15V, and no load current. The unit of voltage should be written as “V” (with a capital letter), if it is a small letter “v”, the button should be pressed briefly to activate the load-shedding function to return to a large “V”.
Now adjust the cutoff voltage for the potentiometer, for example for a 12V acid battery it will be a total discharge voltage of 10.20V (1.7V/cell, different sources may give slightly different sizes, especially depending on its manufacturer). Long press (more than 3 seconds) the load disconnect function button until the letter “V” changes to a small “v”. Turn the voltage potentiometer to the maximum value and leave already - with the isolating load will return to standby.
Now it is enough to set the desired load current, preferably for 20 hours (usually in accordance with the recommendations for acid batteries), for example, 2.5 A for a 50 A / h battery, and wait for the completion signal - beeping. Depending on the condition of the battery, this may take several hours. With the load cut function, you don't have to worry about missing a full discharge and damaging the battery - the load will turn off automatically. On the display we can read the value of the capacitance and the measurement time that has passed.
Capacitance measurement is activated automatically upon detection of a current of at least 50 mA without any operation by pressing the button and adjusting the trip voltage described above - they only serve to activate the voltage control mode and disconnect the load.
One of the processor outputs has a 9600 8N1 USART software transmission in a one second cycle that includes information identical to that shown on the display as ASCII codes. You can send data transmission to, for example, a computer via any RS232-TTL / USB adapter and read the information directly on any terminal by pointing to the appropriate COM port of the adapter. The transmitted data includes ASCII codes that control the terminal, namely CR + LF codes at the ends of the line and a CLRSCR code to clear the screen at the beginning of each transmission, so that the data is displayed in the terminal window in a fixed place (window scrolling when receiving data is not performed) .
The microcontroller directly drives the 2x16 alphanumeric LCD in 4-bit mode. The display shows 6 parameters,
There are several potentiometers in the circuit. They are used to correct voltage and current measurements, as well as display contrast, and to adjust the load current level (coarse and fine), as well as to set the cutoff voltage for A/h measurements.
The power supply is a 3W, 12V power transformer. The standard built-in regulator in the SMD version provides 5V to power the entire circuit, while the 9V regulator in the TO-92 package for the op-amp is soldered on the track side, voltage filtered. several electrolytic capacitors and ceramics.
The electronic circuit was divided into two printed circuit boards: a processor board with interacting circuits and a load board with a transistor and resistors. They are designed to be split in two or left as one large board. In the case of splitting, the boards are connected using short lengths of wires, preferably cables, and placed in the housing so that they are as close to each other as possible (as short as possible connecting wires). The power transistor is attached to a fairly large heatsink with a fan.
The whole circuit was placed in a typical metal case from an ATX computer power supply. A front panel with a hole for the display is attached to one of the walls. In addition to the display, there are also banana plugs for connecting the source under test and adjustment potentiometers. Due to the fact that this is a case from a computer power supply, there is already a connector for a 220 V power cord.
Hello. In my review today, I will talk about a battery tester. It is by no means a measuring device. You can call it a battery conductivity tester, a battery analyzer, a battery status indicator, or simply a "display meter". But its essence does not change from this. It will allow you to quickly find out the status of your car battery or uninterruptible power supply. This type of tester is able to determine whether the battery is in good condition, whether it needs to be recharged or whether it is time to change it. If you are interested - welcome under cat.
I'll warn you right away. These testers are not designed to measure the cold cranking current (CCA) of new batteries, they are designed to check and evaluate the condition of used batteries. Any indication of the CCA or the current state of health (state of health) of the battery cannot be considered completely reliable.
So, what is cold scroll current in a battery? And this is one of the most important characteristics of the battery. If the battery capacity affects only the number of attempts to start your car, then the cold scroll current is the maximum current given by the battery for 3 to 30 seconds at a temperature of -18 degrees (this depends on the measurement technique. We mainly use the EN standard) . On the marking of car batteries, in addition to capacity, this value is always present. Starting current is a relative value. And it is very different in the new and old battery. Therefore, it is better to choose a battery with a margin for starting current, so that over time you will not experience problems with starting. Especially in cold weather. For example, if your starter draws 250 amps, you should not choose a battery with a starting current of less than 350 amps. Otherwise, your battery will die prematurely. But let's not talk about sad things ...
So, as I wrote above, we have the most common method for determining the cold scroll current EN:
EN (European standard EN 50342.1 2006, formerly EN 60095-1)The test is also carried out at -180C. EN requirements are divided into 2 methods - EN1 and EN2.
EN1 - Battery voltage after 10 seconds should be 7.5 V. Then a break is taken for 10 seconds, and the battery is discharged further at the initial current multiplied by 0.6. The second stage lasts 73 seconds, and in general the entire period of the discharge takes 90 seconds (assuming that the initial period is 10 seconds / 0.6 = 16.7 seconds).
EN2 - Same as EN1 except that the second discharge period is to 6V for 133 seconds and the total test time is 150 seconds. The ratio of discharge currents corresponding to both methods depends largely on the type of battery and can vary from car to car and from design to design. Based on a comparative analysis, the following relationship between EN1 and EN2 can be derived:
EN2 = 0.85% to 0.92% EN1.
You can do without this plate. Roughly speaking, CCA is about 10% higher than EN.
The first such testers under the brand name "Kulon" were and are being produced by a Russian manufacturer. But these testers cost, and are worth a lot of insane money. If you are interested, you can find the price yourself, so that I would not be accused of advertising.
Therefore, it is time to go directly to the hero of today's review and see how this tester evaluates the condition of the battery.
The order was made on December 6th. In fact, it was pre-ordered. And, after the AE300 tester appeared in stock, it was shipped on December 27 by a courier company. And, since there is no representative office in my city, the company sent a package from the city closest to me using EMS and on January 18, just on my birthday, I had it:
The tester itself comes in a blister pack:
In addition to the tester, the kit includes an instruction in English:
Instruction
And here is the hero of today's review - the AE300 battery tester:
Crocodiles are made with high quality and have contact pads made of non-ferrous metal:
Two wires are suitable for each crocodile, each soldered to its contact pad on both sides:
The opening width of crocodiles is 3 centimeters:
There are five buttons on the front panel of the tester:
The up and down arrows are used to select the CCA digits of the battery before starting the measurement, the SEL button selects the digit of the number. Button "OK" - serves to confirm, as well as start testing. On / off button - serves, as you might guess, to turn the tester on and off. The tester does not have its own power source and is powered by a connected battery.
Behind - there is a sticker with the name of the tester:
Let's open it:
The tester determines the internal resistance of the battery using the principle.
When measuring with a tester, the battery is not discharged and a whole series of measurements can be carried out without the risk of "landing" the battery, which is impossible with other methods of verification, for example, by discharge or a load plug.
The tester uses an eight-bit microcontroller with flash memory -:
What formulas and constants for calculating the capacity are hardwired into the controller, unfortunately, is not known. As the firmware of the tester "Pendant" is still unknown. But whatever it is, it works.
AE300 board from the front:
So, the tester allows you to check the CCA of the battery. But what if you need to check the battery, where CCA is not indicated? For example, a battery from a UPS? You can check!
And although, as I wrote above, the tester was created to test batteries already in use, but only a new one was at hand, out of the box, a 7 Ah UPS battery:
Let the readings be incorrect, but using his example, I will tell you how to check batteries that do not have CCA current indicated.
There is a formula according to which the approximate CCA of a battery is equal to the battery capacity divided by 0.0725. Later, in the video, using the example of an already used UPS battery, you can see that this value is chosen quite correctly. Based on this, it is possible to convert the SSA value of similar batteries obtained by the tester into Ah by multiplying the obtained value by the same constant - 0.0725. Just do not forget, this is an approximate capacity that allows you to assess the condition of the battery.
So, since the battery is 7 Ah, we divide 7 by 0.0725. We get 96.55. The closest value that can be set on the tester is 95.
We connect the tester first to the plus, and then to the minus of the battery, observing the polarity. We press the power button. The countdown from 0 to 9 will start on the screen. After the countdown, press the "OK" button, otherwise the countdown will be repeated until you press the button.
4 zeros will appear, the digit of the number that can be changed will flash. We set the desired value with the up / down arrows. The digit of the number is changed with the "SEL" button:
When the desired value is entered, press the "OK" button. The measurement will begin, taking just a few seconds:
When the measurement is completed, the tester will display the results and beep periodically. We press "OK". The beep will turn off.
So what do we see. And we see the bar at the top, filled to 100%. This is the general state of battery life. The state is written above the bar. If the condition is poor, you should think about purchasing a new battery.
Below is the voltage, measured quite accurately. Given that it measures correctly.
And the bottom line is the internal resistance of the battery. For 7 Ah UPS batteries, it should be in the range of 20-25 mOhm. If the resistance is higher, the battery must be replaced.
Press the "SEL" button and get to the second page of measurements:
And, if everything is correct on the first page, then the second page will be unreliable, since the battery is new and has not yet been used.
095 is the SSA we recorded.
130.9 is the measured SSA. This will happen with new batteries. But, for example, when buying a new one, you can take a measurement, and focus more on internal resistance than on capacitance. Although the measured SSA, which is less than the prescribed one, is a reason to be wary, but are you being sold a battery in the store that had been lying on the shelf for several years before the sale? And such a battery is better not to buy.
After the measurement, we press the shutdown button, and then disconnect the negative clamp from the battery, and then the positive one.
Let's move on to the car battery.
The battery has been in operation for three and a half years. The measurements were performed at negative temperatures. Accordingly, the parameters will be somewhat underestimated. The amendments are also written in the instructions for the tester.
As you can see, here the starting current of 520A (EN) is indicated on the battery case. Let's convert it to SSA. According to the table at the beginning of the review, 520A EN = 550 CCA. Therefore, before measuring, enter the number 550 into the tester and measure:
Battery internal resistance = 7.21 mΩ. For car batteries - the norm of internal resistance is 5 - 8 mOhm. If the resistance is higher, it's time to change the battery.
The overall battery life is just above 60%. What is rated by the tester as OK, in contrast to GOOD in the case of a UPS battery. When the battery condition is from 40 to 60% - it's time to think about replacing it. Less than 40% - you run the risk of not starting even in the summer.
Switch with the "SEL" key to the second screen:
With the specified cold scroll current of 550A CCA, we have a total of 324.7A CCA. This suggests that by next winter it is worth thinking about replacing the battery.
I shot a short video, though not of very high quality, because it was inconvenient to shoot a video with a camera, while manipulating the tester. But in the video you can see the measurement results of various batteries, and there will also be several consecutive measurements to check the repeatability of the result:
Well, the most valuable thing is the ability to assess the condition of the batteries without disconnecting them from the circuit. This is very convenient, especially when there are hundreds of batteries. I have already managed to identify many batteries that are on the verge of exhaustion and need to be replaced. Selective testing of batteries rejected by the tester confirmed his correctness.
Thank you for your attention.
The product was provided for writing a review by the store. The review is published in accordance with clause 18 of the Site Rules.
I plan to buy +38 Add to favorites Liked the review +77 +113Greetings, citizens of Datagoria! Let me introduce you to my next creation - a battery capacity tester. The device, of course, is not for every day, but sometimes the seams without it!
I needed to measure the remaining capacity of the acid battery, because in winter every Ampere counts, maybe it's time to replace the battery? Simple tests with a load fork and density measurement did not suit me, they did not give me information about whether I had enough energy to warm up the car for 40 minutes on the PZhD (about 8 A / h) and then start the car with a starter.
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Controlled Discharge Controller
Arrangement of fuses when programming MK ATmega8A
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Igor Kotov, editor-in-chief of Datagor magazine
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Each car owner is wondering what kind of device is needed to measure battery capacity. This value is often measured during scheduled maintenance, but it will be useful to learn how to determine it yourself.
Battery capacity is a parameter that determines the amount of energy given off by the battery at a certain voltage in one hour. It is measured in A / h (Ampere per hour), and depends on which is determined by a special device - a hydrometer. When buying a new battery, the manufacturer indicates all the technical parameters on the case. But this value can be determined by yourself. For this, there are special devices and methods.
The easiest way is to take a special tester, for example "Pendant". This is a modern device for measuring the capacity of a car battery, as well as its voltage. In this case, you will spend the minimum amount of time and get a reliable result. To check, you need to connect the device to the battery terminals and within a few seconds it will determine not only the capacity, but also the battery voltage and the condition of the plates. However, there are other battery capacities.
For example, a multimeter can be used as a device for measuring the capacity of a car battery, but you will not get accurate readings with it. A prerequisite for this method (called the test discharge method) is that the battery is fully charged. First you need to connect a powerful consumer to the battery (a regular 60W light bulb is quite suitable).
You can also use the method in which the battery is discharged through a resistor using a special circuit. Using a stopwatch, we determine the time spent on the discharge. Since energy will be lost at a voltage within 1 Volt, we can easily determine using the formula I \u003d UR, where I is the current, U is the voltage, R is the resistance. In this case, it is necessary to avoid the complete discharge of the battery, using, for example, a special relay.
If it is not possible to purchase a ready-made device, you can always assemble a device for measuring battery capacity with your own hands.
To determine the degree of charge and capacity of the battery, you can use There are many models of ready-made plugs for sale, but you can assemble it yourself. The following is one of the options.
This model uses an extended scale, which achieves high measurement accuracy. There is a built-in load resistor. The scale is divided into two ranges (0-10 V and 10-15 V), which further reduces the measurement error. The device also has a 3 volt scale and a different measuring device lead, making it possible to test individual battery cells. The 15V scale is achieved by reducing the voltage on the diode and zener diode. The current value of the device increases if the voltage value exceeds the opening level of the zener diode. When a voltage of the wrong polarity is applied, the protective function is performed by the diode.
In the diagram: R1- transmits the required current to the zener diode; R2 and R3 - resistors selected for the M3240 microammeter; R4 - determines the width of the narrow range of the scale; R5 - load resistance, switched on by the SB1 toggle switch.
The load current strength is determined by Ohm's law. Load resistance is taken into account.
The capacity of AA batteries is measured in mAh (milliamps per hour). To measure such batteries, you can use special chargers that determine the current, voltage and capacity of the battery. An example of such a device is the AccuPower IQ3 battery capacity meter, which has a power supply with a voltage range of 100 to 240 volts. To measure, you will need to insert batteries into the device, and all the necessary parameters will appear on the display.
Also, the capacity can be determined using a conventional charger. Having determined the magnitude of the charge current (it is indicated in the characteristics of the device), it is necessary to fully charge the battery and record the time spent on this. After multiplying these two values, we get the approximate capacity.
More accurate readings can be obtained using another method, for which you will need a fully charged battery, a stopwatch, a multimeter and a consumer (you can use, for example, a flashlight). We connect the consumer to the battery, and with the help of a multimeter we determine the current consumption (the smaller it is, the more reliable the results). We note the time during which the flashlight shone, and multiply the result by the current consumption.
