The voltage of a car battery is the potential difference across the pole terminals. For greater accuracy, it is recommended to measure the voltage when the transients caused by the charging or discharging current have ended. Their duration can be several hours, and the voltage change can reach 0.6-1.8 Volts. Although it is generally accepted that car starter batteries have a nominal voltage of 12 Volts, in reality the voltage of a new charged battery is in the range of 12.7-13.3 Volts.

The capacity of the battery is characterized by the amount of electricity, measured in ampere-hours, received from the battery when it is discharged to a set final voltage of 10.5 Volts and a temperature of 20 degrees. During normal operation, it is not recommended to discharge a car battery below its final voltage. Otherwise, its service life is sharply reduced.

The value of the battery capacity allows you to calculate the approximate time it delivers (or operates) the average current to the load. The capacity depends on the strength of the discharge current, so during testing the discharge conditions are standardized. The discharge current is set to 0.05 Cp for a 20-hour discharge mode and 0.1 Cp for 10 hours. For a battery with a capacity of 60 Ah, it is, respectively, 3 Amperes and 6 Amperes. At such currents, the capacity of the new one corresponds to the nominal value. And for a discharge current of 25 Amps, the typical capacity of this battery is 40 Ah. This capacity will provide power to electrical equipment for 96 minutes.

40 Ah x 60 minutes / 25 Ampcr = 96 minutes.

The current value of 25 A was not adopted in the tests by chance. It is believed that this is the current consumption of the electrical equipment of a typical passenger car. With starter currents, the capacity of a car battery can drop 5 times relative to the nominal value. So, for a 6ST-55A battery with a starter current of 250 A and a temperature of minus 18 degrees, the capacity is only 10 Ah instead of 55 Ah. And yet this value will provide a total starter cranking time of 2.4 minutes.

10 Ah x 60 minutes / 250 Amps = 2.4 minutes.

The capacity of a car battery decreases very sharply at negative temperatures and already at minus 20 degrees it decreases to 40-50%

Reducing the cold cranking current and the capacity of the 6ST-55 battery as the temperature drops.

With a larger capacity, a car battery also produces a higher cold cranking current. For example, a 55 Ah capacity provides a current of 420-480 Ampere according to the EN standard and 250-290 Ampere according to DIN, a battery with a capacity of 62 Ah provides a current of 510 Ampere according to the EN standard and 340 Ampere according to DIN, and a 77 Ah battery already provides 600 Ampere according to EN and 360 Amps according to DIN.

Cold start current (Cold Cranking Ampere - CCA) of a car battery, requirements of DIN 43539 T2, EN 60095-1, SAE, IEC 95-1 (IEC 95-1).

The cold start current of a car battery determines its maximum starting capacity, that is, how much current the battery can deliver at a temperature of minus 18 degrees at the end of a given time interval, until the battery voltage drops to the required minimum level. The DIN and EN standards provide for two checks on the process of discharging a car battery to a voltage of 6 Volts.

The first check is carried out 30 seconds from the start of the discharge, and it measures the voltage U30 of the battery, which for the DIN standard must be greater than 9 Volts, and for the EN standard - greater than 7.5 Volts. The second check consists of measuring the duration of the T6v discharge until the battery voltage reaches 6 Volts, which should be at least 150 seconds.

There are four standards, DIN 43539 T2, EN 60095-1, SAE, IEC 95-1, which define the duration of the test interval and the permissible minimum voltage of a car battery, the requirements for which are indicated in the table below

The SAE and IEC standards only define the limiting voltage value U30. For ease of comparison, the cold cranking current values ​​of a car battery can be converted from one standard to another. Currents are recalculated using the following formulas.

Isae = 1.5Idin + 40 (A)
Iiec = Idin/0.85 (A)
Ien = Idin/0.6 (A)
Idin = 0.6Ien (A)

Values ​​in the EN standard are rounded.

— At a current of less than 200 A in 10 A increments.
— At a current of 200-300 A in steps of 20 A (220, 240, 260, 280 A).
- At a current of 300-600 A in steps of 30 A (330, 360, 390 A, etc.).

For example, a VARTA battery with a capacity of 55 Ah has a DIN current of 255 Ampere. Using the above formulas, we get for Isae = 422.5 Ampere, Iiec = 300 Ampere, Ien = 425 Ampere, rounding - 420 A.

Typically, the cold start current of a car battery is 6.5-7.5 times higher than the nominal capacity. The number of possible engine starts over the entire service life of a car battery ranges from 4,000 for low-maintenance batteries and up to 12,000 for specially designed batteries, such as the Optima battery, according to the manufacturer.

It is believed that in one year, during operation of moderate intensity, from 1,000 to 2,000 engine starts are made. Thus, the service life of a car battery can be from 4 to 2 years. We note in view of the importance that the cold start current CCA, in accordance with the standards, is standardized by each car battery manufacturer only for a temperature of minus 18 degrees. The manufacturer does not provide data for lower temperatures.

For fully charged and new battery with a capacity of 50-60 Ah, the cold cranking current is in the range of 300-500 Amperes. If the starting current of a typical 6ST-55 battery at a temperature of plus 25 degrees is 400 Amperes, then at a temperature of minus 30 degrees it will drop to 200 A. With each new attempt at an unsuccessful start, its value will be less and less. Although battery production technologies are improving, these changes have had almost no effect on the degree to which their starting current decreases at subzero temperatures.

Reserve capacity (RC - residual capacity) of a car battery.

The reserve capacity or residual capacity of a car battery is rarely indicated in the battery data sheet, but it is important for the consumer because it shows the time during which the battery will keep the car running if the car fails. At the same time, current consumption by all vehicle systems is normalized to 25 Amperes.

The reserve capacity of a car battery is defined as the period of time in minutes during which the battery can maintain a discharge current of 25 Amps until the voltage drops to 10.5 Volts. The standards do not establish a requirement for the amount of reserve capacity. For many batteries with a capacity of 55 Ah, the reserve capacity reaches 100
minutes, which is a good indicator.

Internal resistance of a car battery.

Typical internal resistance values ​​for a new car battery are 0.005 ohms at room temperature. It consists of the resistance between the electrodes and the electrolyte and the resistance of the internal connections. Towards the end of its service life, the internal resistance of a car battery increases many times, which leads to the fact that the battery cannot crank.

Based on materials from the book “Tutorial for installing car theft protection systems.”
Naiman V. S., Tikheev V. Yu.

4.2 - 0.22 = 3.98 Volts.

And this is a completely different matter... If we take and connect five such parallel sections in series, we will get a battery with a voltage -

Ubat=3.98V*5=19.9 Volts, capacity -
Sbat=2.2A/h*5=11A/h….

capable of delivering a current of 10 Amperes to the load....
Something like that…

P.S. ….I caught myself thinking that pleasure can also be measured in A/h…..

____________________

I agree that the method described above can lead to a large error in measuring internal resistance, but..., in fact, the absolute value of this resistance is of little interest to us - what is important to us is the method itself, which will make it possible to objectively and quickly assess the “health” of each element …Practice has shown that the resistances of elements differ significantly…, and knowing only the value of internal resistance, you can easily find “simulators”….
Measuring the internal resistance of LiFePO4 elements designed for very high discharge currents may cause some difficulties associated with the need to load them with very high currents... but I can’t say anything about this, since I practically haven’t done this....

How to measure the internal resistance of a battery

If we close the plus and minus of the battery, we get current short circuit Ie = U/Re, as if there is resistance inside Re. Internal resistance depends on the electrochemical processes inside the element, including current.

If the current is too high, the battery will deteriorate and may even explode. Therefore, do not short the plus and minus. Enough thought experiment.

Size Re can be estimated indirectly by changes in current and voltage across the load Ra. With a slight decrease in load resistance Ra to Ra‑dR, the current increases from Ia to Ia+dI. The voltage at the output of the element Ua=Ra×Ia decreases by the amount dU = Re × dI. Internal resistance is determined by the formula Re = dU / dI

To estimate the internal resistance of a battery or battery, I added a 12-ohm resistor and a toggle switch (a button is shown in the diagram below) to change the current by dI = 1.2 V / 12 Ohm = 0.1 A. At the same time, you need to measure the voltage on the battery or resistor R .

Can be done simple diagram only for measuring internal resistance according to the pattern shown in the figure below. But it’s still better to first discharge the battery a little and then measure the internal resistance. In the middle, the discharge characteristic is flatter and the measurement will be more accurate. The result is an “average” value of internal resistance, which remains stable for quite a long time.

Example of determining internal resistance

We connect the battery and voltmeter. Voltmeter shows 1.227V. Press the button: the voltmeter shows 1.200V .
dU = 1.227V – 1.200V = 0.027V
Re = dU / dI = 0.027V / 0.1A = 0.27 Ohm
This is the internal resistance of the element at a discharge current of 0.5A

The tester does not show dU, but simply U. In order not to make mistakes in the mental calculation, I do this.
(1) I press the button. The battery begins to discharge and the voltage U begins to decrease.
(2) At the moment when the voltage U reaches a round value, for example 1.200V, I press the button and immediately see the value U+dU, for example 1.227V
(3) New numbers 0.027V - and there is the desired dU difference.

As batteries age, their internal resistance increases. At some point you will find that the capacity of even a freshly charged battery cannot be measured, since when you press the button Start The relay does not turn on and the clock does not start. This happens because the battery voltage immediately drops to 1.2V or less. For example, with an internal resistance of 0.6 ohms and a current of 0.5 A, the voltage drop will be 0.6 × 0.5 = 0.3 volts. Such a battery cannot operate at a discharge current of 0.5A, which is required, for example, for a ring LED lamp. This battery can be used at a lower current to power a watch or wireless mouse. It is precisely because of the large value of internal resistance that modern charging device, like the MH-C9000, determine that the battery is faulty.

Internal resistance of a car battery

To evaluate the internal resistance of the battery, you can use a lamp from a headlight. It should be an incandescent lamp, for example, a halogen, but not an LED. A 60W lamp consumes 5A current.

At a current of 100A, the internal resistance of the battery should not lose more than 1 Volt. Accordingly, at a current of 5A, more than 0.05 Volts (1V * 5A / 100A) should not be lost. That is, the internal resistance should not exceed 0.05V / 5A = 0.01 Ohm.

Connect a voltmeter and a lamp in parallel to the battery. Remember the voltage value. Turn off the lamp. Notice how much the voltage has increased. If, say, the voltage increases by 0.2 Volt (Re = 0.04 Ohm), then the battery is damaged, and if by 0.02 Volt (Re = 0.004 Ohm), then it is working. At a current of 100A, the voltage loss will be only 0.02V * 100A / 5A = 0.4V

Internal battery resistance. What is the internal resistance of a battery?
1. What is the internal resistance of a battery? Let's take a lead acid battery with a capacity of 1 A*hour and a rated voltage of 12 V. In a fully charged state, the battery has a voltage of approximately U= 13 V. What is the current I will flow through the battery if a resistor with resistance is connected to it R=1 Ohm? No, not 13 amperes, but somewhat less - about 12.2 A. Why? If we measure the voltage on the battery to which the resistor is connected, we will see that it is approximately equal to 12.2 V - the voltage on the battery has dropped due to the fact that the diffusion rate of ions in the electrolyte is not infinitely high. Electricians are used to making calculations electrical circuits from elements with several poles. Conventionally, one can imagine a battery as a two-terminal network with EMF (electromotive force - voltage without load) E and internal resistance r. It is assumed that part of the battery EMF drops at the load, and the other part drops at the internal resistance of the battery. In other words, it is assumed that the formula is correct: Why is the internal resistance of a battery a conditional value? Because a lead battery is a fundamentally nonlinear device and its internal resistance does not remain constant, but changes depending on the load, battery charge and many other parameters, which we will talk about a little later. Therefore, accurate calculations of battery performance must be made using the discharge curves provided by the battery manufacturer, and not the internal resistance of the battery. But to calculate the operation of circuits connected to the battery, the internal resistance of the battery can be used, each time being aware of what value we are talking about: the internal resistance of the battery during charging or discharging, the internal resistance of the battery during DC or variable, and if variable, then what frequency, etc. Now, returning to our example, we can roughly determine the internal resistance of a 12 V, 1 Ah DC battery. r = (E - U) / I = (13V - 12.2V) / 1A = 0.7 Ohm. 2. How are the internal resistance of a battery and the conductivity of a battery related? By definition, conductivity is the reciprocal of resistance. Therefore, the conductivity of the battery S is the inverse of the internal resistance of the battery r. The SI unit of battery conductivity is Siemens (Sm). 3. What does the internal resistance of a battery depend on? The voltage drop across a lead battery is not proportional to the discharge current. At high discharge currents, ion diffusion electrolyte discharge occurs in free space, and at low battery discharge currents it is strongly limited by the pores of the active substance of the battery plates. Therefore, the internal resistance of the battery at high currents is several times (for lead battery) is less than the internal resistance of the same battery at low currents.	As you know, high-capacity batteries are larger and more massive than small-capacity batteries. They have a larger working surface of the plates and more space for electrolyte diffusion inside the battery. Therefore, the internal resistance of high-capacity batteries is less than the internal resistance of smaller-capacity batteries. Measurements of the internal resistance of batteries at constant and alternating current show that the internal resistance of the battery is highly dependent on frequency. Below is a graph of battery conductivity versus frequency, taken from the work of Australian researchers. It follows from the graph that the internal resistance of a lead-acid battery has a minimum at frequencies of the order of hundreds of hertz. At high temperatures, the rate of diffusion of electrolyte ions is higher than at low temperatures. This dependence is linear. It determines the dependence of the internal resistance of the battery on temperature. At higher temperatures, the internal resistance of the battery is lower than at low temperatures. During battery discharge, the amount of active mass on the battery plates decreases, which leads to a decrease in the active surface of the plates. Therefore, the internal resistance of a charged battery is less than the internal resistance of a discharged battery. 4. Can the internal resistance of the battery be used to test the battery? Devices for testing batteries have been known for quite some time, the operating principle of which is based on the relationship between the internal resistance of the battery and the battery capacity. Some devices (load forks and similar devices) offer to evaluate the condition of the battery by measuring the voltage of the battery under load (which is similar to measuring the internal resistance of a battery at direct current). The use of others (alternating current battery internal resistance meters) is based on the connection of internal resistance with the state of the battery. The third type of devices (spectrum meters) allows you to compare the spectra of internal resistance of batteries running on alternating current of different frequencies and draw conclusions about the condition of the battery based on them. The internal resistance (or conductivity) of the battery itself allows only a qualitative assessment of the condition of the battery. In addition, manufacturers of such devices do not indicate at what frequency the conductivity is measured and with what current the test is performed. And, as we already know, the internal resistance of the battery depends on both frequency and current. Consequently, conductivity measurements do not provide quantitative information that would allow the user of the device to determine how long the battery will last the next time it is discharged to the load. This drawback is due to the fact that there is no clear relationship between the battery capacity and the internal resistance of the battery. The most modern battery testers are based on analyzing the oscillogram of the battery's response to a special waveform. They quickly estimate the battery capacity, which allows you to monitor the wear and aging of a lead battery, calculate the duration of the battery discharge for a given state, and make a forecast of the remaining life of the lead battery.
Protect the environment. Do not throw away worn-out batteries - take them to a specialized company for recycling.

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The impedance of a lead-acid battery is the sum of polarization resistance and ohmic resistance. Ohmic resistance is the sum of the resistances of the battery separators, electrodes, positive and negative terminals, connections between cells and electrolyte.

The resistance of the electrodes is influenced by their design, porosity, geometry, lattice design, state of the active substance, the presence of alloying components, and the quality of the electrical contact of the lattice and coating. The resistance values ​​of the negative electrode arrays and the sponge lead (Pb) on them are approximately the same. At the same time, the resistance of lead peroxide (PbO2), which is applied to the positive electrode grid, is 10 thousand times greater.

During the discharge of a lead-acid battery, lead sulfate (PbSO4) is released on the surface of the electrodes. This is a poor conductor, which significantly increases the resistance of the electrode plates. In addition, lead sulfate is deposited in the pores of the plate coating and significantly reduces the diffusion of sulfuric acid from the electrolyte into them. As a result, by the end of the discharge cycle of a lead-acid battery, its resistance increases by 2-3 times. During the charging process, lead sulfate dissolves and the battery resistance returns to its original value.

The resistance of the lead-acid battery has a significant impact on the resistance of the electrolyte. This value, in turn, strongly depends on the concentration and temperature of the electrolyte. As the temperature decreases, the resistance of the electrolyte increases and reaches infinity when it freezes.

With an electrolyte density of 1.225 g/cm3 and a temperature of +15 C, it has a minimum resistance value. As the density decreases or increases, the resistance increases, which means the internal resistance of the battery also increases.

The resistance of separators changes depending on changes in their thickness and porosity. The amount of current that flows through the battery affects the polarization resistance. A few words about polarization and the reasons why it occurs. The first reason is that in the electrolyte and on the surface of the electrodes (double electric layer) electrode potentials change. The second reason is that when current passes, the electrolyte concentration changes in the immediate vicinity of the electrodes. This leads to a change in the electrode potentials. When the circuit opens and the current disappears, the electrode potentials return to their original values.

One of the features of lead-acid batteries is their low internal resistance compared to other types of batteries. Thanks to this, they can deliver high current (up to 2 thousand amperes) in a short time. Therefore, their main area of ​​application is starter motors. rechargeable batteries on vehicles with internal combustion engines.

It is also worth noting that the internal resistance of the battery at alternating or direct current strongly depends on its frequency. There are a number of studies whose authors observed the internal resistance of a lead-acid battery at a current frequency of several hundred hertz.

How can you estimate the internal resistance of a battery?

As an example, consider a 55 Ah car lead-acid battery with a nominal voltage of 12 volts. A fully charged battery has a voltage of 12.6-12.9 volts. Let's assume that a resistor with a resistance of 1 ohm is connected to the battery. Let the voltage of the open battery be 12.9 volts. Then the current should theoretically be 12.9 V / 1 Ohm = 12.9 amperes. But in reality it will be below 12.5 volts. Why is this happening? This is explained by the fact that in an electrolyte the rate of diffusion of ions is not infinitely large.

The image shows the battery as a 2-pole power source. It has an electromotive force (EMF), which corresponds to the open circuit voltage, and internal resistance. In the diagram they are designated E and Rin. When the circuit is closed, the emf of the battery partially drops across the resistor, as well as through the internal resistance itself. That is, what happens in the circuit can be described by the following formula.

E = (R + Rin) * I.

You can see in the images below EMF values car battery in an open circuit and voltage when connecting a load in the form of two car light bulbs connected in parallel.

This may be of interest to those who like to measure the internal resistance of batteries. The material in some places does not qualify as entertaining reading. But I tried to present it as simply as possible. Don't shoot the pianist. The review turned out to be huge (and even in two parts), for which I offer my deepest apologies.
A short list of references is provided at the beginning of the review. The primary sources are posted in the cloud, there is no need to search.

0. Introduction

I bought the device out of curiosity. It’s just that on various chat rooms in RuNet on the issues of measuring the internal resistance of galvanic elements, somewhere on page 20-30, messages appeared about the wonderful Chinese device YR1030, which measures this very internal resistance both confidently and absolutely correctly. At this point, the debate subsided, the topic collapsed and smoothly went into the archives. Therefore, links to lots with YR1030 were lying around on my wish list for a year and a half. But the toad was strangling, there was always a reason to dump the “accumulated by back-breaking labor” into something more interesting or useful.
When I saw the first and only lot of YR1035 on Ali, I immediately understood: the hour had struck, I had to take it. It's either now or never. And I’ll figure out the confusing question about internal resistance before the device reaches me. post office. I paid for the purchase and began to figure it out. I wish I hadn't done this. As they say: the less you know, the better you sleep. The results of the proceedings are summarized in Part II of this report. Check it out at your leisure.

I bought the YR1035 in the maximum configuration. On the product page it looks like this:


And I have never regretted what I did (in terms of the completeness of the package). In fact, all 3 ways to connect the YR1035 to a battery/battery/whatever are needed (or can be useful) and complement each other very well.
The front panel in the photo looks bruised, but it is not. The seller just removed the protective film first. Then I thought about it, stuck it back and took a photo.
The whole thing cost me 4,083 rubles ($65 at current exchange rates). Now the seller has raised the price a little, because at least sales have begun. And the reviews on the product page are overwhelmingly positive.
The set was packed very well, in some kind of strong box (I’m writing from memory, everything was thrown away a long time ago). Inside, everything was laid out in separate zip-top bags made of polyethylene and packed tightly, without hanging out anywhere. In addition to the probes in the form of paired tubes (pogo pins), there was a set of spare tips (4 pcs.). There is information about these same pogo pins here.

GLOSSARY of abbreviations and terms

HIT- chemical current source. There are galvanic and fuel. Further we will talk only about galvanic HIT.
Impedance (Z)– complex electrical resistance Z=Z’+iZ’’.
Admittance– complex electrical conductivity, the reciprocal of impedance. A=1/Z
EMF– “purely chemical” potential difference between the electrodes in a galvanic cell, defined as the difference in the electrochemical potentials of the anode and cathode.
NRC- the voltage of an open circuit, for single elements is usually approximately equal to the EMF.
Anode(chemical definition) – the electrode at which oxidation occurs.
Cathode(chemical definition) – the electrode at which reduction occurs.
Electrolyte(chemical definition) – a substance that in a solution or melt (i.e. in a liquid medium) disintegrates into ions (partially or completely).
Electrolyte(technical, NOT chemical definition) - a liquid, solid or gel-like medium that conducts electricity due to the movement of ions. To put it simply: electrolyte (technical) = electrolyte (chemical) + solvent.
DES- double electrical layer. Always present at the electrode/electrolyte interface.

LITERATURE – everything is posted in the library ON THE CLOUD

A. According to internal measurements. resistance and attempts to extract at least some useful information from this
01. [I highly recommend reading Chapter 1, everything is very simple there]
Chupin D.P. Parametric method for monitoring the performance characteristics of rechargeable batteries. Diss... uch. Art. Ph.D. Omsk, 2014.
Read only chapter 1 (Literary review). Next up is another invention of the wheel...
02. Taganova A.A., Pak I.A. Sealed chemical current sources for portable equipment: Handbook. St. Petersburg: Khimizdat, 2003. 208 p.
Read – Chapter 8 “Diagnostics of the state of chemical power sources”
03. [it’s better not to read this, there are more errors and typos, but nothing new]
Taganova A. A., Bubnov Yu. I., Orlov S. B. Sealed chemical current sources: elements and batteries, equipment for testing and operation. St. Petersburg: Khimizdat, 2005. 264 p.
04. Chemical current sources: Handbook / Ed. N.V. Korovina and A.M. Skundina. M.: Publishing house MPEI. 2003. 740 p.
Read – section 1.8 “Methods of physical and chemical research of chemical chemicals”

B. By impedance spectroscopy
05. [classics, three books below are simplified and shortened books by Stoinov, manuals for students]
Stoinov, 3.B. Electrochemical impedance / 3.B. Stoinov, B.M. Grafov, B.S. Savova-Stoinova, V.V. Elkin // M.: “Nauka”, 1991. 336 p.
06. [this is the shortest version]
07. [this is a longer version]
Zhukovsky V.M., Bushkova O.V. Impedance spectroscopy of solid electrolytic materials. Method. allowance. Ekaterinburg, 2000. 35 p.
08. [this is an even more complete version: expanded, in-depth and chewed]
Buyanova E.S., Emelyanova Yu.V. Impedance spectroscopy of electrolytic materials. Method. allowance. Ekaterinburg, 2008. 70 p.
09. [you can scroll through Murzilka - a lot of beautiful pictures; I found typos and obvious blunders in the text... Attention: it weighs ~100 MB]
Springer Handbook of Electrochemical Energy
The most interesting section: Pt.15. Lithium-Ion Batteries and Materials

V. Inf. leaflets from BioLogic (impact spectroscopy)
10. EC-Lab - Application Note #8-Impedance, admittance, Nyquist, Bode, Black
11. EC-Lab - Application Note #21-Measurements of the double layer capacitance
12. EC-Lab - Application Note #23-EIS measurements on Li-ion batteries
13. EC-Lab - Application Note #38-A relation between AC and DC measurements
14. EC-Lab - Application Note #50-The simplicity of complex number and impedance diagrams
15. EC-Lab - Application Note #59-stack-LiFePO4(120 pcs)
16. EC-Lab - Application Note #61-How to interpret lower frequencies impedance in batteries
17. EC-Lab - Application Note #62-How to measure the internal resistance of a battery using EIS
18. EC-Lab - White Paper #1-Studying batteries with Electrochemical Impedance Spectroscopy

D. Comparison of internal measurement methods. resistance
19. H-G. Schweiger et al. Comparison of Several Methods for Determining the Internal Resistance of Lithium Ion Cells // Sensors, 2010. No. 10, pp. 5604-5625.

D. Reviews (both in English) on SEI - protective layers on the anode and cathode in Li-Ion batteries.
20. [short review]
21. [full review]

E. GOST standards - where would we be without them... Not everything is in the cloud, only those that are at hand.
GOST R IEC 60285-2002 Alkaline batteries and accumulators. Nickel-cadmium batteries sealed cylindrical
GOST R IEC 61951-1-2004 Rechargeable batteries and rechargeable batteries containing alkaline and other non-acid electrolytes. Portable sealed batteries. Part 1. Nickel-cadmium
GOST R IEC 61951-2-2007 Rechargeable batteries and batteries containing alkaline and other non-acid electrolytes. Portable sealed batteries. Part 2. Nickel-metal hydride
GOST R IEC 61436-2004 Rechargeable batteries and batteries containing alkaline and other non-acid electrolytes. Sealed nickel-metal hydride batteries
GOST R IEC 61960-2007 Rechargeable batteries and batteries containing alkaline and other non-acid electrolytes. Lithium batteries and rechargeable batteries for portable use
GOST R IEC 896-1-95 Lead-acid stationary batteries. General requirements and test methods. Part 1. Open types
GOST R IEC 60896-2-99 Lead-acid stationary batteries. General requirements and test methods. Part 2. Closed types

1. Briefly for those who use the YR1030 or at least know why it is needed
(if you don’t know yet, then skip this point for now and go straight to step 2. It’s never too late to return)

In short, the YR1035 is essentially the YR1030 with some improvements.

What do I know about the YR1030?

(translation of Mooch - “Beggar” ;))



Here is a video of how our craftsman built one that connects to the YR1030.
There are several sellers selling Ali YR1030, 1-2 are on eBay. Everything that is sold there does not come with the “Vapcell” label. I visited the Vapcell website and found it with great difficulty.
I got the impression that Vapcell has about the same relationship to the development and production of YR1030 as Muska has to the Bolshoi Theater ballet. The only thing Vapcell brought to the YR1030 was to translate the menu from Chinese to English and package it in a beautiful cardboard box. And he raised the price by 1.5 times. After all, it’s a “brand” ;).

YR1035 differs from YR1030 in the following ways.

1. Added 1 digit in the voltmeter line. There are 2 surprising things here.
A) Amazingly high accuracy of potential difference measurements. It is the same with top-end DMMs for 50 thousand samples (a comparison with Fluke 287 will be made below). The device has clearly been calibrated, which is good news. So that category was added for a reason.


b) A rhetorical question:
Why is it needed, such incredible accuracy, if this voltmeter is used for its intended purpose, i.e. for measuring NRC (open circuit voltage)?
A very weak argument:
On the other hand, a device for 50-60 Baku can periodically act as a home standard DC voltmeter. And none and their signs are from the Chinese, who often turn out to be outright misinformation.

2. Finally a dull USB, to which the electrodes/probes are connected in the YR1030, was replaced with a much more sane four-pin cylindrical connector (I couldn’t find the name, I think the comments will tell you the correct name).
UPD. The connector is called XS10-4P. Thank you !


Responsible both in terms of fastening and in terms of durability/reliability of contacts. Of course, the probes for the coolest (stationary) meters are at the end of each of the 4 wires via BNS, but molding 4 mating parts onto a small lightweight box of the YR1035 housing... That would probably be too much.

3. The upper limit of voltage measurement was raised from 30 volts to 100. I don’t even know how to comment on this. Personally, I won't risk it. Because I don't need it.

4. The charging connector (micro-USB) was moved from the top to the bottom end of the body. It has become more convenient to use the device while recharging the built-in battery.

5. Changed the color of the case to dark, but left the front panel glossy.

6. A bright blue edging was made around the screen.

So, an unknown Chinese company worked hard to improve the YR1030 ---> YR1035 and made at least two useful innovations. But which ones exactly – each user will decide for himself.

2. For those who don’t know what it is and why it is needed

As you know, there are people in the world who are interested in such a parameter of HIT as its internal resistance.
“This is probably very important for users. There is no doubt that the option to measure internal resistance will contribute to the growth of sales of our wonderful test chargers,” the Chinese thought. And they stuck this thing into all sorts of Opuses, Liitocals, iMaxes and so on and so forth... The Chinese marketers were not mistaken. Such a feature cannot but cause anything but quiet joy. Only now this is implemented in one place. Well, then you will see for yourself.

Let's try to apply this “option” in practice. Let's take [for example] Lii-500 and some kind of battery. The first one I came across was a “chocolate” one (LG Lithium Ion INR18650HG2 3000mAh). According to the datasheet, the internal resistance of the chocolate bar should be no more than 20 mOhm. I made 140 consecutive measurements of R in all 4 slots: 1-2-3-4-1-2-3-4-... etc., in a circle. The result is a plate like this:

Green indicates values ​​of R = 20 mOhm and less, i.e. "just what the doctor ordered." There are 26 of them in total or 18.6%.
Red - R = 30 mOhm or more. There are 13 of them in total or 9.3%. Presumably, these are so-called misses (or “departures”) - when the resulting value differs sharply from the “hospital average” (I think many have guessed why half of the departures are in the first two rows of the table). Perhaps they should be discarded. But to do this reasonably, you need to have a representative sample. To put it simply: make the same type of independent measurements many, many times. And document it. Which is exactly what I did.
Well, the overwhelming number of measurements (101 or 72.1%) fell within the range of 20< R< 30 мОм.
This table can be transferred to the histogram (values ​​68 and 115 are discarded as obvious outliers):


Oh, something is already becoming clearer. Here, after all, the global maximum (in statistics – “mode”) is 21 mOhm. So this is the “true” value of the internal resistance of the LG HG2? True, there are 2 more local maxima on the diagram, but if you build a histogram according to the rules of applied statistics. processing, they will inevitably disappear:

How it's done

Open the book (on page 203)
Applied statistics. Fundamentals of econometrics: In 2 volumes – T.1: Ayvazyan S.A., Mkhitaryan V.S. Probability theory and applied statistics. – M.: UNITY-DANA, 2001. – 656 p.

We build a grouped series of observations.
Measurements in the range of 17-33 mOhm form a compact set (cluster) and all calculations will be made for this cluster. What to do with the measurement results 37-38-39-68-115? 68 and 115 are obvious misses (departures, emissions) and should be discarded. 37-38-39 form their own local mini-cluster. In principle, it can also be ignored further. But it is possible that this is a continuation of the “heavy tail” of this distribution.
Number of observations in the main cluster: N = 140-5 = 135.
a) R(min) = 17 mOhm R(max) = 33 mOhm
b) Number of intervals s = 3.32lg(N)+1 = 3.32lg(135)+1 = 8.07 = 8 (rounded to the nearest integer)
Interval width D = (R(max) – R(min))/s = (33 – 17)/8 = 2 mOhm
c) Midpoints of intervals 17.5, 19.5, 21.5…

The diagram shows that the distribution curve is asymmetrical, with the so-called. "heavy tail" Therefore, the arithmetic average for all 140 measurements is 24.9 mOhm. If we discard the first 8 measurements while the contacts were “grinding” against each other, then 23.8 mOhm. Well, the median (distribution center, weighted average) is a little more than 22...
You can choose any of the methods for estimating the value of R. Because the distribution is asymmetric and therefore the situation is ambiguous***:
21 mOhm (mode on histogram No. 1),
21.5 mOhm (mode on histogram No. 2),
22 mOhm (median),
23.8 mOhm (arithmetic mean with correction),
24.9 mOhm (arithmetic mean without correction).
***Note. In the case of an asymmetric distribution in statistics, it is mildly recommended to use the median.

But with any choice, it turns out that R is greater than [the maximum permissible for a living, healthy, well-charged battery] 20 mOhm.

I have a request to readers: repeat this experiment on your own copy of an internal resistance meter like Lii-500 (Opus, etc.). Just at least 100 times. Make a table and draw a distribution histogram for some battery with a known datasheet. The battery should not necessarily be fully charged, but close to it.
If you think of preparing the contacting surfaces - cleaning, degreasing (which the author did not do), then the scatter between measurements will be smaller. But he will still be there. And noticeable.

3. Who is to blame and what to do?

Next, two natural questions arise:
1) Why do the readings fluctuate so much?
2) Why is the internal resistance of the chocolate bar, found using any of the above criteria, always greater than the limit value of 20 mOhm?

To the first question There is a simple answer (known to many): the very method of measuring small R values ​​is fundamentally wrong. Because a two-contact (two-wire) connection circuit is used, sensitive to TSC (transient contact resistance). The PSC is comparable in magnitude to the measured R and “walks” from measurement to measurement.
And you need to measure using a four-pin (four-wire) method. This is exactly what is written in all GOST standards. Although no, I’m lying – not in all of them. This is in GOST R IEC 61951-2-2007 (extreme for Ni-MeH), but not in GOST R IEC 61960-2007 (for Li)***. The explanation for this fact is very simple - they simply forgot to mention it. Or they didn’t consider it necessary.
***Note. Modern Russian GOSTs for HIT are international IEC (International Electrotechnical Commission) standards translated into Russian. The latter, although they are advisory in nature (a country may or may not accept them), but once adopted, become national standards.
Under the spoiler are pieces of GOST standards mentioned above. Something that relates to the measurement of internal resistance. You can download full versions of these documents from the cloud (link at the beginning of the review).

Measurement of internal resistance of HIT. How it should be implemented. From GOST 61960-2007 (for Li) and 61951-2-2007 (for Ni-MeH)

By the way, under the spoiler is answer to the second question(why does the Lii-500 produce R>20 Ohms).
Here is a place from the LG INR18650HG2 datasheet, where these same 20 mOhms are mentioned:


Pay attention to what is highlighted in red. LG guarantees the internal resistance of the element is no more than 20 mOhm, if it is measured at 1 kHz.
For a description of how this should be done, look under the spoiler above: paragraphs “Measurement of internal resistance using the a.c.” method.
Why was 1 kHz frequency chosen and not another? I don't know, that's what we agreed on. But there were probably reasons. This point will be discussed in the next section. very detailed.
Moreover, in all the alkaline type HIT datasheets (Li, Ni-MeH, Ni-Cd) that I had to look through, if internal resistance was mentioned, it referred to a frequency of 1 kHz. True, there are exceptions: sometimes there are measurements at 1 kHz and at direct current. Examples under the spoiler.

From datasheets of LG 18650 HE4 (2.5Ah, aka “banana”) and “pink” Samsung INR18650-25R (2.5Ah)

LG 18650 HE4


Samsung INR18650-25R

Devices like YR1030/YR1035 allow you to measure R (more precisely, total impedance) at a frequency of 1 kHz.
R(a.c.) of this instance LG INR18650HG2 ~15 mOhm. So everything is fine.


And at what frequency does all this happen in the “advanced” test chargers under consideration? At a frequency equal to zero. This is mentioned in GOST standards “Measurement of internal resistance using the d.c. method.”
Moreover, in test chargers this is not implemented as described in the standards. And not the way it is implemented in diagnostic equipment from different manufacturers (CADEX and the like). And not in the way it is considered in scientific and pseudo-scientific studies on this matter.
And “according to concepts” known only to the manufacturers of those same test kits. The reader may object: what difference does it make how to measure? The result will be the same... Well, there is an error, plus or minus... It turns out there is a difference. And noticeable. This will be discussed briefly in section 5.

The main thing you need to realize and come to terms with:
A) R(d.c.) and R(a.c.) are different parameters
b) the inequality R(d.c.)>R(a.c.) always holds

4. Why are the internal resistance of the HIT at direct current R(d.c.) and alternating current R(a.c.) different?

4.1. Option #1. The simplest explanation

This is not even an explanation, but rather a statement of fact (taken from Taganova).
1) What is measured at direct current R(d.c.) is the sum of two resistances: ohmic and polarization R(d.c.) = R(o) + R(pol).
2) And when at AC, and even at the “correct” frequency of 1 kHz, R(pol) disappears and only R(o) remains. That is, R(1 kHz) = R(o).
By at least, IEC experts, Alevtina Taganova, as well as many (almost everyone) who measure R(d.c.) and R(1 kHz) would like to hope for this. And by simple arithmetic operations he obtains R(o) and R(pol) separately.
If this explanation suits you, then you don’t have to read Part II (formatted as a separate review).

Suddenly!
…
Due to the limited scope of reviews on Muska, sections 4 and 5 were removed. Well, like, “Appendix”.
...

6. YR1035 as a voltmeter

This additional option present in all decent devices of this kind (battery analyzer, battery tester).
A comparison was made with the Fluke 287. The devices have approximately the same voltage resolution. The YR1035 even has a little more - 100 thousand samples, and the Fluke - 50 thousand.

The Corad-3005 LBP acted as a source of constant potential difference.


The results obtained are in the table.


Match to the fifth significant digit. It's funny. In fact, you rarely see such unanimity between two instruments calibrated on opposite ends of the world.
I decided to make a collage as a keepsake :)

7. YR1035 as an ohmmeter

7.1 Testing at “high” resistances

From what was found, an improvised “resistance store” was put together:


To which the YR1035 and Fluke were alternately connected:


Fluke’s original monstrous probes were forced to be replaced with more suitable situations, because with the “relatives” it is even very problematic to set the “delta” (due to their rubber-coated protection at level 80 600B+IV class - horror, in short):


The result is a table like this, expanded and supplemented:

Well what can I say.
1) For now, you should pay attention to the results obtained Mooch
2) Regarding what was received Danish at low resistances: apparently, with the zero setting on the YR1030 it didn’t work out very well - the reasons will be explained below.
By the way, it’s not clear from the Nordic stingy:
- resistance measurements what objects he carried out?
- How he did this, having in his hands a standard box from Vapcell with a device, a note in broken English and “4 terminal probes” = two pairs of Pogo pins? Photo from his review:

7.2 Test on a conductor with a resistance of ~5 mOhm

How can we do without the classics of the genre: determining the resistance of a single conductor according to Ohm’s law? No way. This is sacred.


The test subject was a copper core in blue insulation with a diameter of 1.65 mm (AWG14 = 1.628 mm) and a length of 635 mm. For ease of connection, it was bent into something meander-like (see photo below).
Before the measurement, zero was set on the YR1035 and compensation R was made (long press the “ZEROR” button):


In the case of Kelvin probes, it is more reliable to short-circuit as shown in the photo, and not “each other”. Well, this is the case that they are as simple as in this set, and not gilded.
Don't be surprised that as a result it was not possible to set 0.00 mOhm. On YR1035 0.00 mOhm - this happens extremely rarely. Usually it turns out from 0.02 to 0.05 mOhm. And then, after several attempts. The reason is unclear.

Next, the chain was assembled and measurements were taken.


It is interesting that the YR1035 itself acted as an accurate voltmeter (measuring the voltage drop ΔU on the core) (see the previous paragraph: YR1035 as a voltmeter is the same Fluke, but with a higher resolution). The source was a Corad-3005 LBP in voltage stabilization mode (1 V).
According to Ohm's law
R(exp) = ΔU(YR1035)/I(Fluke) = 0.01708(V)/3.1115(A) = 0.005489 Ohm = 5.49 mOhm
At the same time, YR1035 showed
R(YR1035) = 5.44 mOhm
Since “ZEROR” was 0.02 mOhm, then
R(YR1035) = 5.44 - 0.02 = 5.42 mOhm
Difference
R(exp) – R(YR1035) = 5.49 - 5.42 = 0.07 mOhm
This is an excellent result. In practice, hundreds of mOhms are hardly interesting to anyone. And correctly shown tenths are already enough through the roof.

The obtained result agrees well with the reference data.


In their opinion, 1 m of AWG14 core made of “correct” electrical copper should have a resistance of 8.282 mOhm, which means this sample should have given R(exp) ~ 8.282x0.635 = 5.25 mOhm. A if you correct for the actual diameter of 1.65 mm, you get 5.40 mOhm. It's funny, but The 5.42 mOhm obtained on the YR1035 is closer to the “theoretical” 5.40 mOhm, than what is obtained according to the “classics”. Maybe the “classic” chain is a little crooked? In the next paragraph this assumption will be tested.
By the way, the sign states that on a core of this diameter there is no need to be afraid of the intrigues of the skin effect up to a frequency of 6.7 kHz.
For those who did not take a general physics course at university:
1)
2)

7.3 Checking the adequacy of the test chain

Yes, this happens too. “Verification of verification” sounds funny (like “certificate that a certificate has been issued”). But where to go...

In the previous paragraph, an implicit assumption was made that a circuit assembled according to the Ohm value gives a slightly more accurate estimate of the value of the core resistance and the difference of 0.07 mOhm is a consequence of the larger error of YR1035. But a comparison with the “theoretical” plate suggests the opposite. So which method of measuring small R is more correct? This can be checked.
I have a pair of FHR4-4618 DEWITRON 10 mOhm high precision shunts ()


At relatively small currents (units of amperes), these resistors have a relative error not exceeding 0.1%.
The connection diagram is the same as in the case of a copper wire.
The shunts are connected using four wires (because this is the only correct way):


Measurements of 1 and 2 copies of FHR4-4618:




Calculation of resistances according to Ohm's law R(1, 2) = ΔU(YR1035)/I(Fluke).
sample No. 1 R(1) = 31.15(mV)/3.1131(A) = 10.006103… = 10.01 mOhm
sample No. 2 R(2) = 31.72(mV)/3.1700(A) = 10.006309… = 10.01 mOhm(round to 4th significant figure)
Everything fits together very well. It's a shame that ΔU couldn't be measured to 5 significant figures. Then one could rightfully state that the shunts are almost identical:
R(1) = 10.006 mOhm
R(2) = 10.006 mOhm

What does the YR1035 look like on those shunts?
And it basically shows *** this (on one, on the other):


Since in compensation mode 0.02 mOhm was again obtained, this is R = 10.00 mOhm.
De facto, this is an amazing coincidence with the Ohm shunt measurements.
Which is good news.
***Note. After compensation (0.02 mOhm), 20 independent measurements were made on each of the shunts. Then the YR1035 was turned off, turned on, compensation was made (again it turned out to be 0.02 mOhm). And again, 20 independent measurements were made. The first shunt almost always produces 10.02 mOhm, sometimes 10.03 mOhm. On the second - almost always 10.02 mOhm, sometimes - 10.01 mOhm.
Independent measurements: connected the crocodiles - measurement - removed the crocodiles - pause 3 seconds - connected the crocodiles - measurement - removed the crocodiles - ... etc.

7.4 Regarding compensation R

Regarding Kelvin clamps - see paragraph 7.2.
With other connection methods, compensation is more complicated. And in the case of a holder, it is less predictable in terms of obtaining the desired result.

A. The most severe case is the R compensation of the crib-holder. The problem is the alignment of the central needle electrodes. Compensation is carried out (usually) in several stages. The main thing is to get into the range less than 1.00 mOhm. But even at R< 1.00 мОм, если прибор после состыковки показывает нечто больше 0.30 мОм, то окончательная компенсация до 0.02… 0.05 мОм часто не происходит. В конце-концов путем многократных попыток (… сомкнул электроды – долгое нажатие «ZEROR» – разомкнул – долгое нажатие «ZEROR» – ...) удается-таки добиться желаемого

B. In the case of 2 pairs of Pogo pins, for a long time I could not understand how to compensate them
more or less predictable. In the description of one of the lots on Ali, the seller showed a photo where pairs of electrodes are crossed. Naturally, this turned out to be misleading. Then I decided to cross them by color: white with white, colored with colored. It has become an order of magnitude better. But I began to completely predictably fall into the range of 0.00 – 0.02 mOhm after I came up with and mastered the level 80 method:
- accurately align the jagged ends of the electrodes (white with white, color with color) and press towards each other until it stops


- wait for the numbers to appear on the screen
- move the fingers of one hand to the contact area and squeeze tightly, and with the finger of the other hand make a long press “ZEROR” (without releasing the second hand this is unlikely to happen, because the buttons in the device are very tight)

8. Amplitude and shape of the test signal

From a review by a Dane: this is the test signal for Vapcell YR1030:
- classic pure harmonic(sinus)
- scope 13 mV(in case anyone has forgotten, this is a value equal to the difference between the highest and lowest voltage values).


What is shown in the Dane’s picture is truly a classic method of electrochemical impedance spectroscopy (see Part II of the review): an amplitude of no more than 10 mV + pure sine wave.
I decided to check it out. Fortunately, a simple oscilloscope is available.

8.1 First attempt - past the cash register. Dull.

Before taking measurements with an oscilloscope:

- let it warm up for 20 minutes.

- started the auto-tuning

Then I connected the YR1035 via Kelvin clamps to the DSO5102P probe.
Directly, without a resistor or battery.

As a result: 6 modes ---> 2 curve shapes.


In Murzilkas for beginner radio amateurs you can find the simplest explanations of how this could happen.
Slightly distorted square wave:

The 2nd form signal can be obtained by superimposing a 5 kHz sinusoid with an amplitude 10 times smaller on a 1 kHz sinusoid:


In resistance measurement modes up to 2 ohms, the oscillation peak-to-peak is 5.44 V.
If more than 2 Ohms or “Auto” - 3.68 V.
[And it should be 3 (three) orders of magnitude less!]

I made a video: how the oscillograms change when moving from one mode to another (in a circle). In the video, the picture changes on the oscilloscope screen with a slowdown of 32 times relative to the “directly on the screen” mode, because averaging is set after capturing and obtaining 32 frames (oscillograms). First, the card for the upper limit of the mode is placed, then a click is heard - it was I who switched the YR1035 to this mode.

It is unlikely that the Dane took his small-amplitude sine wave from the ceiling. He may be careless about some points, but he has never noticed that he would misinform.
That means I was doing something wrong. But what?
Left to think. A couple of weeks later it dawned on me.

8.2 Second attempt - it seemed to work. But it's much more complicated than expected.

Thinking out loud. It feels like what I was filming was not test signals. These are like “detection signals”. And the test ones are sinusoids with a small range. Then another question - why in different modes they differ? Both in shape and amplitude?

Well, okay, let's measure.
Before taking measurements with an oscilloscope (again):
- reset settings to factory settings
- let it warm up for 20 minutes.
- launched automatic calibration
- started the auto-tuning
- checked the probe - 1x ideal meander 1 kHz
Then I connected the YR1035 through Kelvin clamps and DSO5102P probes to a 0.2 Ohm resistance from the “resistance store” (see section 7.1). In the popularly favorite operating mode of the AUTO oscilloscope, you can see this picture:


And even then, if you guess to set the correct horizontal scan, in the kilohertz region. Otherwise, it's a complete mess.
Any not very advanced oscilloscope user knows what to do next.
I go into the channel settings and set the high frequency limit to “20.” “20” means 20 MHz. It would be great if it were 4 orders of magnitude less - 2 kHz. But, despite everything, this has already helped:


In fact, everything is much better than what is in the photo. Most of the time the signal is the one in the photo that is bold. But sometimes, several times a minute it starts to “adjust” within 1-2 seconds. It was this moment that was captured.
Then I press the ACQUIRE button to configure the sampling parameters. Real Time --> Average --> 128 (averaging over 128 pictures).


Such strict “noise reduction” is needed only for very small resistances. At 22 Ohms, in principle, averaging over 4-8 oscillograms is already enough, because the level of the useful (test) signal is an order of magnitude higher.

Next is the MEASURE button and the necessary information on the right side of the screen:


Measurements were made similarly for 5 and 22 Ohms




The piece of 5.5 mOhm wire that appeared in section 7.2 drank the most blood.


Nothing worked for a long time, but in the end we managed to get something like this:


Do not pay attention to the current frequency value: it changes there every 1-2 seconds, and jumps in the range from 800 Hz to 120 kHz

What's in the bottom line :

Resistance (Ohms) - test signal peak-to-peak (mV)
0.0055 - 1.2-1.5
0.201 - 2.4-2.6
5.00 - 5.4-6.2
21.8 - 28-32
The amplitude slowly “walks” up and down.

9. Settings menu

Settings menu in Chinese. Switching to any other language is not available as a class. It’s good that at least they left Arabic numbers and English letters indicating the dimensions of quantities. :). I have not found a clear translation into English, let alone the great and mighty one, anywhere, so I present my version below. I think it will fit the YR1030 too.
To enter the settings menu, you need to briefly press the “POWER” button while the device is turned on (if you press it for a long time, a confirmation menu for turning off the device will pop up). The “correct” exit from the settings mode to the measurement mode is with the “HOLD” button (exception: if the cursor is on section No. 1, then you can exit in any of two ways: by pressing the “POWER” button, or by pressing the “HOLD” button )
The menu has 9 sections (see table below).
Moving through sections:
- down, book. "RANGE U" (in a circle)
- up, book. "RANGE R" (in a circle).
Enter the section settings using the “POWER” button
Pressing “POWER” again returns to the main menu - WITHOUT SAVING CHANGES made by the user!
In order for CHANGES TO BE SAVEd, exit the section to the list of sections only with the “HOLD” button!
After entering the section, changeable parameters and the purpose of the button appear. “RANGE R” changes - it only works to increase the value of the value (but in a circle).
Book "RANGE U" moves the selection by changing values ​​only downwards (but in a circle).
Luckily, the sections are numbered, so using the sign I whipped up shouldn't be too difficult. In some I still haven’t figured out the points, but I probably shouldn’t go into it unless absolutely necessary. The device works like that.

10. Offal

The device can be easily disassembled. The front panel is held on by 4 screws. The control board with the screen is also attached to 4 screws (smaller ones).




Charging is via a regular micro-USB port. The algorithm is standard, two-stage CC/CV. Maximum consumption ~0.4-0.5 A. Current cutoff at the final stage of CV occurs at 50 mA. At this moment, the potential difference across the battery is 4.197 V. Immediately after turning off the charge, the voltage drops to 4.18 V. After 10 minutes it is about 4.16 V. This is a well-known phenomenon associated with the polarization of the electrodes and electrolyte during charging. This is most pronounced in low-capacity batteries. U H.K.J. There are a couple of studies on this.
After turning on the device, under load, another small drawdown is added:


The YR1035 estimates the internal resistance of its 1kHz battery to be 86 mOhm. For inexpensive Chinese 18300s, this figure is quite common. I cannot give a guarantee that the result obtained is 100% correct, since the battery was not disconnected from the device.
One moment causes irritation, a little infuriates, causes surprise: the device is turned off, you put it on charge - it turns on. What's the point?

12. Interfaces for connecting to the object under study

I thought for a long time about how to title this paragraph. And it turned out so pathetic.
It is clear that the object of study can be not only a battery or an accumulator, but now we will talk about them. That is, using the device for its intended purpose. In all three cases, the same wires are used in soft “silicone” insulation and of approximately the same length - from 41 to 47 cm. Through a magnifying glass it was possible to make out that they are “20 AWG”, “200 deg. C”, “600 V” , silicone (all this relates to insulation) and the name of the manufacturer from 2 unfamiliar words.

12.1 Kelvin alligator clips


The simplest and most convenient connection method, but practically inapplicable for “ordinary” cylindrical HITs. I tried connecting it this way and that on unprotected 18650s - nothing worked. By the way, for the measurement of R to take place, the crocodiles’ sponges must be separated at least a little... The numbers on the screen jump and fly within 1-2 orders of magnitude.
But measuring anything that has a terminal in the form of a wire or plate is a pleasure (see practical examples above). This is probably obvious to everyone.

12.2 Pogo pins


The best zero setting results, both in quality and predictability. If you do it as described above (section 7.4), let me remind you:


Designed for express measurements. Well suited for CCI with relatively wide flat cathodes (+).


Although, if you wish, you can get clever and measure the same Enelup AA. At least this happened to me several times. But not the first time. But with Enelup AAA this number did not work. Therefore, the “Geltman set” contains the so-called. crib-holder (I don’t know what to call it differently, more scientifically).

12.3 Crib-holder (holder) or Kelvin crib BF-1L
The thing is very specific and relatively expensive. At the time I received the subject, I already had a couple of exactly the same ones lying around. I bought it last fall at a price of $10.44/piece (including shipping). Then they weren’t on Ali, but after NG they appeared on Ali. Keep in mind that they come in two sizes with a limitation on the length of the cylindrical HIT: up to 65 mm and up to 71 mm. A holder for a larger size has the letter “L” (Long) at the end of its name. Both the holders from Fasta and the sabzhevy one are just the size “L”.

Such holders were not purchased at Fast by chance: there was an idea to replace them (I spotted them from a Dane H.K.J.) a collectively converted clamp from Leroy for this very “crib”:


It later turned out that the purchase was premature. I never switched to four-wire measurements of charge-discharge curves for HIT. And “Kelvin’s crib” turned out to be one hell of a thing in terms of usability. Let's put it this way: the people who invented it initially assumed that a person had three arms. Well, or in the process of installing the HIT into the holder, 1.5 people are involved. By the way, a chimpanzee would be a good fit - she even has one more grip than she needs. Of course, in principle you can get used to it. But it often turns out all wrong (see photo of this holder with the battery inserted at the end of section 3). If the cathode of the element is small, then you should not bother with nonsense, but put something underneath. Starting with plain paper:


In terms of the limitation on the diameter of the element - theoretically it seems to exist, but in practice I have not yet encountered it. Here, for example, is a measurement on an element of size D:


The dimensions of the cathode plate allow you to stick the element to the probes at the bottom of the plate and take measurements.
By the way, you don’t need to put anything underneath. ;)

13. Conclusion

Overall, the YR1035 was a pleasant surprise. He “can” do everything that is required of him, and even with a specific margin both in sensitivity (resolution) and in the quality of measurements (very small error). I was pleased that the Chinese approached the improvement process informally. The YR1030 is not better than the YR1035 in any respect, except price (the difference is insignificant - a few bucks). At the same time, the YR1035 is clearly superior to its predecessor in a number of ways (see the beginning of the review and photo of the internals).

About competitors
1) For example, there is this:


In the world - SM8124 Battery Impedance Meter. On all sorts of different electronic platforms and in Chinese stores this goodness is through the roof.
Here are micro-reviews: and. This orange miracle matches the YR1035 in all respects, does not have a zero setting (compensation), there is only one way to connect to the HIT (“pogo pins”), and has the funny property of dying if you mix up the plus and minus when connecting to the HIT (which is even written about in the instructions). But happy owners claim that nothing bad happens at 5V. Probably we need more... In the eevblog.com thread on this thing, the Dane sadly declares: “I have one of these, but it is dead. I do not know why (I have not looked inside it).”
By the way, the YR1030 and YR1035 are completely indifferent to polarity reversal: they simply show the potential difference with a minus. And the measured impedance value does not depend in any way on polarity.
AND main point is the division of the total impedance on Z into Z’ and Z’’. Explicit or implicit (more tailored to the end user). This is both good and correct.
Unfortunately, they are not free from the main problem of devices of this kind - measuring Z (even with division into Z’ and Z’’) at a fixed frequency of 1 kHz is a kind of “shooting in the dark”. The fact that 1 kHz was blessed in all IEC recommendations (which later became standards) does not change the essence. To understand this point, it is advisable to read part II of this opus. And not diagonally, as far as possible.

All the best.

- Remark from 05/22/2018
The review is huge and in the process of layout.
Suddenly I found it with a Dane. It hasn't been there for sure since at least a month ago.
There was nothing at all about YR1035 a month ago on the Internet. Except one lot for Ali and one for Tao. And now there are already about 6-7 lots on Ali and a short review has appeared.
Well, well, there will be something to compare with.

I'm planning to buy +30 Add to favorites I liked the review +78 +116

A source is a device that converts mechanical, chemical, thermal and some other forms of energy into electrical energy. In other words, the source is an active network element designed to generate electricity. Various types The sources available in the electrical network are voltage sources and current sources. These two concepts in electronics are different from each other.

Constant voltage source

A voltage source is a device with two poles; its voltage is constant at any time, and the current passing through it has no effect. Such a source will be ideal, having zero internal resistance. In practical conditions it cannot be obtained.

An excess of electrons accumulates at the negative pole of the voltage source, and a deficiency of electrons at the positive pole. The states of the poles are maintained by processes within the source.

Batteries

Batteries store chemical energy internally and are capable of converting it into electrical energy. The batteries cannot be recharged, which is their disadvantage.

Batteries

Rechargeable batteries are rechargeable batteries. When charging, electrical energy is stored internally as chemical energy. During unloading, the chemical process occurs in the opposite direction and electrical energy is released.

Examples:

1. Lead-acid battery cell. It is made from lead electrodes and electrolytic liquid in the form of sulfuric acid diluted with distilled water. Voltage per cell - about 2 V. V car batteries six cells are usually connected in a series circuit, at the output terminals the resulting voltage is 12 V;

1. Nickel-cadmium batteries, cell voltage – 1.2 V.

Important! For small currents, batteries and accumulators can be considered as a good approximation of ideal voltage sources.

AC voltage source

Electricity is produced at power stations using generators and, after voltage regulation, is transmitted to the consumer. AC voltage home network 220 V in various power supplies electronic devices easily converted to a lower value when using transformers.

Current source

By analogy, how an ideal voltage source creates constant pressure at the output, the task of the current source is to produce a constant current value, automatically controlling the required voltage. Examples are current transformers (secondary winding), photocells, collector currents of transistors.

Calculation of the internal resistance of the voltage source

Real voltage sources have their own electrical resistance, which is called "internal resistance". The load connected to the source terminals is designated as “external resistance” - R.

A battery of batteries generates EMF:

ε = E/Q, where:

• E – energy (J);
• Q – charge (C).

The total emf of a battery cell is its open circuit voltage when there is no load. It can be checked with good accuracy using a digital multimeter. The potential difference measured at the output terminals of the battery when it is connected to a load resistor will be less than its voltage when the circuit is open, due to the flow of current through the external load and through the internal resistance of the source, this leads to the dissipation of energy in it as thermal radiation .

The internal resistance of a chemical battery is between a fraction of an ohm and a few ohms and is mainly due to the resistance of the electrolytic materials used in the manufacture of the battery.

If a resistor with resistance R is connected to a battery, the current in the circuit is I = ε/(R + r).

Internal resistance is not a constant value. It is affected by the type of battery (alkaline, lead-acid, etc.), and changes depending on the load value, temperature and period of use of the battery. For example, with disposable batteries, the internal resistance increases during use, and the voltage therefore drops until it reaches a state that is unsuitable for further use.

If the emf of the source is a predetermined quantity, the internal resistance of the source is determined by measuring the current flowing through the load resistance.

1. Since the internal and external resistance in the approximate circuit are connected in series, you can use Ohm's and Kirchhoff's laws to apply the formula:

1. From this expression r = ε/I – R.

Example. A battery with a known emf ε = 1.5 V is connected in series with a light bulb. The voltage drop across the light bulb is 1.2 V. Therefore, the internal resistance of the element creates a voltage drop: 1.5 - 1.2 = 0.3 V. The resistance of the wires in the circuit is considered negligible, the resistance of the lamp is not known. Measured current passing through the circuit: I = 0.3 A. It is necessary to determine the internal resistance of the battery.

1. According to Ohm's law, the resistance of the light bulb is R = U/I = 1.2/0.3 = 4 Ohms;
2. Now, according to the formula for calculating the internal resistance, r = ε/I – R = 1.5/0.3 – 4 = 1 Ohm.

In the event of a short circuit, the external resistance drops to almost zero. The current can only be limited by the small resistance of the source. The current generated in such a situation is so strong that the voltage source may be damaged by the thermal effects of the current and there is a risk of fire. The risk of fire is prevented by installing fuses, for example in car battery circuits.

The internal resistance of a voltage source is an important factor when deciding how to deliver the most efficient power to a connected electrical appliance.

Important! Maximum power transfer occurs when the internal resistance of the source is equal to the resistance of the load.

However, under this condition, remembering the formula P = I² x R, an identical amount of energy is transferred to the load and dissipated in the source itself, and its efficiency is only 50%.

Load requirements must be carefully considered to decide on the best use of the source. For example, a lead-acid car battery must deliver high currents at a relatively low voltage of 12 V. Its low internal resistance allows it to do this.

In some cases, power supplies high voltage must have extremely high internal resistance to limit the short-circuit current.

Features of the internal resistance of the current source

An ideal current source has infinite resistance, but for genuine sources one can imagine an approximate version. The equivalent electrical circuit is a resistance connected to the source in parallel and an external resistance.

The current output from the current source is distributed as follows: part of the current flows through the highest internal resistance and through the low load resistance.

The output current will be the sum of the currents in the internal resistance and the load Io = In + Iin.

It turns out:

In = Io – Iin = Io – Un/r.

This relationship shows that as the internal resistance of the current source increases, the more the current across it decreases, and the load resistor receives most of the current. Interestingly, voltage will not affect the current value.

Real source output voltage:

Uout = I x (R x r)/(R +r) = I x R/(1 + R/r).

Current strength:

Iout = I/(1 + R/r).

Output power:

Rout = I² x R/(1 + R/r)².

Important! When analyzing circuits, we proceed from the following conditions: when the internal resistance of the source significantly exceeds the external one, it is a current source. When, on the contrary, the internal resistance is significantly less than the external one, this is a voltage source.

Current sources are used when supplying electricity to measuring bridges, operational amplifiers, these can be different sensors.

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