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Rechargeable battery discharge current 5 A. Li-Po batteries. Battery specifications

Without a battery, a car turns into useless real estate - only rare modern cars can be started with a push. The battery serves as a power source not only for the starter, but also for numerous electronic devices responsible for the safety or comfort of the vehicle. This is why an unsuitable device can cause a car to fail at the wrong time or even be damaged. To avoid such mistakes, it is worth carefully considering the main characteristics of the car battery.

Compatibility

Modern batteries are as unified as possible, which makes their choice easier, but there are still many differences between batteries. The main distinguishing feature of a battery is its rated voltage. There are three main types of batteries:

6 Volts - for mopeds, buggies, some ATVs and other light equipment;
12 Volt - all cars, most motorcycles and ATVs;
24 Volt - heavy diesel trucks, special equipment.

Of course, there are also non-standard batteries, but only equipment manufactured in a single copy are equipped with them.

Most modern batteries still have the classic lead-acid design. It cannot be called the most efficient, but this technology allows you to achieve an optimal balance between battery characteristics and its cost. Recently, gel batteries have begun to gain popularity. The principle of their operation is similar, however, such batteries contain a very thick electrolyte, which does not allow gases to escape outside - this improves the characteristics of the device and makes it as safe as possible. There are batteries created using nickel-metal hydride technology and lithium batteries (lithium-ion, lithium-polymer, lithium-phosphate) - these are usually intended for hybrid vehicles and are not compatible with the electrical system of a conventional car.

Technologies

The most widespread in Russia are serviced batteries, which require regular topping up of distilled water to maintain the properties of the electrolyte. The main advantage of this technology is the low cost of the product, as well as its excellent reliability. The serviced battery is not afraid of deep discharge and can be restored after long-term storage of the car outdoors in the cold. A very popular modification of such batteries is low-maintenance devices that require replenishing the supply of distilled water approximately once a year versus 2–3 times for conventional maintenance batteries. Such devices have an extended service life and greater frost resistance.

However, recently, maintenance-free batteries have entered the Russian market, which do not require topping up electrolyte and can operate without human intervention throughout their entire shelf life. The liquid in their cans can be absorbed into a special fiberglass filler that prevents it from evaporating. In addition, they have recently been developed, the technical characteristics of which also allow them to be called maintenance-free. Thanks to the addition of silicon to the electrolyte, it turns into a thick gel that does not evaporate and does not change its volume even under the influence of strong heat. Gel batteries are considered the safest - due to the complete absence of gas formation, they can be stored even in residential areas.

Since lead does not tolerate long-term exposure to an aggressive environment, which is an electrolyte based on sulfuric acid, it must be alloyed to obtain the required reliability parameters. Antimony is most often used, which makes the battery much more resistant to influences such as heat and hypothermia. However, batteries with a large amount of antimony have a rather serious drawback, which is represented by boiling of the electrolyte when the electrical parameters deviate significantly from the norm. To eliminate this drawback, batteries with other alloying substances were developed - calcium became the most popular.

Calcium batteries are very reliable and durable, and are practically not subject to destruction when exposed to shock loads and vibrations. Calcium sulfate, formed upon contact with sulfuric acid, coats the lead plates of the battery, protecting them from corrosion and excessive overheating during recharging. As a result, calcium-type devices can withstand voltage surges of up to 25% without significant damage. It would seem that calcium batteries, efficient and inexpensive to produce, should completely displace other types of devices from the market. However, it is worth paying attention to the significant disadvantages of such batteries:

Loss of half the capacity during the first deep discharge without the possibility of its subsequent restoration;
After losing 70% of the capacity, there is a possibility of complete failure of the battery - this can happen if the car is left for a long time with the electrical equipment turned on;
Calcium devices must not be used in cars with faulty electrical equipment - this is guaranteed to disrupt their normal operation;
At temperatures below -30 degrees, it is better to store a calcium battery in a warm room - otherwise you will not be able to guarantee its serviceability;
To recharge such a device, you will need an expensive electronically controlled charger.

To overcome the disadvantages of calcium and antimony batteries, many large companies have begun producing hybrid batteries that use both alloying elements. They have moderate reliability and capacity, but are not damaged by deep discharge and do not require compliance with the same strict rules. There are also alternative hybrid batteries in which the second alloying element besides calcium is silver. Such devices are very reliable and durable, and are also immune to rapid deep discharge, but for obvious reasons they are expensive. Low-antimony batteries are also produced, in which the content of the alloying element does not exceed 3% - they are impervious to heat and deep discharge, but have a limited shelf life.

Additional Information

Serviced batteries allow you to control the electrolyte level without the slightest problem - just unscrew the cap of one can to see whether topping up with distilled water is required. However, low-maintenance and maintenance-free devices do not provide this opportunity - without the help of a specialist, it will not be possible to gain access to the internal components of such batteries. Electrolyte density is monitored using a special indicator called a “magic eye”. Depending on the degree of battery wear, it changes its color from green to red, signaling the need for maintenance or replacement of the power source. In models with white walls, the electrolyte level can be measured by shining a flashlight on them.

Many modern batteries are equipped with a porous polyethylene separator, which is installed inside their case - such a device prevents the plates from shorting together and essentially the device. The separator improves the performance of the power source by preventing its destruction due to prolonged exposure to vibrations or strong shocks. Another protective component for the battery is the flame cutter, which prevents fire and explosion when a spark hits the housing. It is used in high-quality devices of serviced and low-maintenance layouts, increasing the level of vehicle protection.

When the battery is very hot, the sulfuric acid contained in the electrolyte can evaporate, forming a caustic aerosol. Its appearance poses a threat to transport safety and also reduces the remaining service life of the device. To eliminate these problems, the aerosol must be captured and deposited back into the tanks. For this purpose, battery caps with a labyrinth shape are used - it allows the electrolyte to precipitate in the form of condensate, flowing into the jars through special channels.

Batteries can be equipped with protective covers and caps that prevent accidental contact of the terminals with metal parts of the car or wires - with their help it is possible to avoid serious problems with the electrical system. Some models of non-standard sizes, for example, Asian batteries or products for special equipment, can be equipped with a set of adapters. They often include pads that allow wide terminals to be secured to thin rods, as well as extended wire lengths for quick polarity changes. Among the features of the batteries, it is necessary to mention the presence of a carrying handle - it helps out motorists who have to lift the power source to a high floor of an apartment building to warm it up.

Optimal choice

When selecting a battery, be sure to pay attention to its compatibility with your car - just reverse the voltage or polarity so that the device is not suitable for the vehicle. Assess the engine size and climatic conditions in which the car will be operated - the capacity and strength of the cold cranking current depend on these parameters. Only after determining these characteristics, proceed to selecting a battery based on its manufacturing technology. If the car will be used in a warm climate, you should give preference to a calcium model, and in a cold climate, a hybrid or low-antimony model. Don't forget to check whether the battery you choose meets reliability and safety standards.

A car starter battery is a chemical current source, the action of which is based on the use of reversible electrochemical processes. The simplest lead-acid battery consists of a positive electrode, the active substance of which is lead dioxide (dark brown), and a negative electrode, the active substance of which is lead sponge (gray). If both electrodes are placed in a vessel with an electrolyte (a solution of sulfuric acid in distilled water), then a potential difference will arise between the electrodes.

When a load (consumer) is connected to the electrodes, electric current will flow in the circuit and the battery will discharge. During the discharge, sulfuric acid is consumed from the electrolyte and at the same time water is released into the electrolyte. Therefore, as a lead battery discharges, the concentration of sulfuric acid decreases, causing the density of the electrolyte to decrease. When charging, reverse chemical reactions occur - sulfuric acid is released into the electrolyte and water is consumed. In this case, the density of the electrolyte increases as it is charged. Since the density of the electrolyte changes during discharges and charges, its value can be used to judge the degree of charge of the battery, which is used in practice.

The main electrical characteristics of a battery are electromotive force, voltage and capacity.

The electromotive force (emf) of a battery is the potential difference between its electrodes when the external circuit is open. The magnitude of the e.m.f. of a working battery depends on the density of the electrolyte (the degree of its charge) and varies from 1.92 to 2.15 volts.

The battery voltage is the potential difference between its terminals, measured under load. The nominal voltage of a lead-acid battery is taken to be 2 volts. The magnitude of the voltage when discharging a battery depends on the magnitude of the discharge current, the duration of the discharge and the temperature of the electrolyte; it is always less than the emf value. Discharging the battery below a certain limit, called the final discharge voltage, is unacceptable, as this can lead to polarity reversal and destruction of the active mass of the electrodes. The magnitude of the charging voltage depends mainly on the degree of charge of the battery, the temperature of the electrolyte and is always greater than the emf value.

Battery capacity is the amount of electricity delivered by a fully charged battery when it is discharged to the permissible final discharge voltage. Battery capacity is measured in ampere-hours and is defined as the product of the discharge current (in amperes) and the duration of the discharge (in hours). The battery capacity depends on the amount of active mass (the number and size of electrodes), the magnitude of the discharge current, the density and temperature of the electrolyte, the service life of the battery and is its most important operational characteristic. At high discharge currents, at low electrolyte temperatures, and also at the end of its service life, the capacity provided by the battery decreases. The nominal capacity of the battery is taken to be the capacity that the battery should deliver when discharged with a 20-hour or 10-hour discharge current, i.e. at a discharge current value numerically equal to 0.05 and 0.1 of the nominal capacity, respectively.

A car starter battery consists of 6 identical batteries connected in series. With this connection, the rated voltage of the battery is equal to the sum of the rated voltages of the individual batteries, and is 12 volts, and the rated capacity of the battery remains the same as the capacity of one battery.

Bringing the battery into working condition

Table 1. Amount of water and acid solution to prepare 1 liter of electrolyte

Required density electrolyte, g/cm³	Quantity water, l	Quantity solution sulfuric acid, density 1.40 g/cm³, l
1,20	0,547	0,476
1,21	0,519	0,500
1,22	0,491	0,524
1,23	0,465	0,549
1,24	0,438	0,572
1,25	0,410	0,601
1,26	0,382	0,624
1,27	0,357	0,652
1,28	0,329	0,679
1,29	0,302	0,705
1,31	0,246	0,760

Car batteries produced in a dry-charged state must be filled with electrolyte in order to be brought into working condition, and after impregnation of the electrodes, measure the density of the electrolyte and recharge the battery. At air temperatures down to -15°C, electrolyte with a density of 1.24 g/cm³ is poured into the batteries. At temperatures from -15° to -30°C, the density is increased to 1.26, and at temperatures below -30° – to 1.28 g/cm³.

An electrolyte of the required density can be prepared directly from acid and water. However, it is more convenient to use an acid solution with a density of 1.40 g/cm³. The amount of water and solution required to prepare 1 liter of electrolyte is indicated in Table 1. Sulfuric acid is counted not in liters, but in kilograms. To convert liters to kilograms, you must use a coefficient of 1.83.

The density of the electrolyte is measured using a hydrometer. It consists of a cylinder with a rubber bulb and an intake tube and a densimeter (float). When determining the density of the electrolyte, it is necessary to squeeze the rubber bulb of the hydrometer with your hand, insert the end of the sampling tube into the electrolyte and gradually release the bulb. After the densimeter floats up, use its scale to determine the density of the electrolyte in the battery. When taking measurements, you must ensure that the densimeter floats freely in the electrolyte (“does not stick” to the cylinder walls).

The density of the electrolyte depends on temperature. The initial electrolyte temperature is considered to be 25°C. For every 15°C change in temperature, the density changes by approximately 0.01 g/cm³. Therefore, when measuring the density of the electrolyte, its temperature should be taken into account and, if necessary, corrections should be made to the hydrometer readings using Table 2.

The electrolyte should be poured into the battery in a thin stream, using a porcelain, polyethylene or ebonite mug and a glass, polyethylene or ebonite funnel.

Table 2. Corrections to hydrometer readings

Temperature electrolyte, C°	Amendment to indications, g/cm 3
-55 to -41	-0,05
-40 to -26	-0,04
-25 to -11	-0,03
-10 to 4	-0,02
From 5 to 19	-0,01
From 20 to 30	0,00
From 31 to 45	+0,01
FROM 46 to 60	+0,02

The electrolyte temperature must be no lower than 15°C and no higher than 25°C. After pouring the electrolyte and impregnating the electrodes, no earlier than 20 minutes and no later than 2 hours, the electrolyte density is monitored. If the density of the electrolyte decreases by no more than 0.03 g/cm³ compared to the density of the electrolyte being poured, the battery can be used. If the electrolyte density drops by more than 0.03 g/cm³, the battery must be recharged. The duration of the first recharge depends on the dry storage period of the battery from the moment of manufacture until it is brought into working condition. The end of recharging is determined by the constant battery voltage and electrolyte density for 2 hours.

Battery charge

Rechargeable batteries are charged when they are brought into working condition, during a control and training cycle, as well as periodically during operation and when discharges are below permissible limits. In preparation for charging, the density and level of electrolyte in all batteries of the battery is measured. In batteries where the level is insufficient, it is brought up to normal by adding distilled water (but not electrolyte!).

Lead-acid batteries must be charged from a DC source. At the same time, a charger designed to charge one 12-volt battery must provide the ability to increase the charging voltage to 16.0-16.5 V, since otherwise it will not be possible to charge a modern maintenance-free battery completely (up to 100% of its actual capacity). The positive wire (terminal) of the charger is connected to the positive terminal of the battery, and the negative wire to the negative terminal. In operational practice, as a rule, one of two methods of charging a battery is used: charging at a constant current or charging at a constant voltage. Both of these methods are equivalent in terms of their impact on battery life.

Charging at a constant current is produced by a current equal to 0.1 of the rated capacity with a 20-hour discharge mode. For example, for a battery with a capacity of 60 Ah, the charging current should be 6 A. To maintain a constant current throughout the charging process, a regulating device is needed. The disadvantage of this method is the need for constant monitoring and regulation of the charging current, as well as abundant gas release at the end of the charge. To reduce gas emission and increase the state of charge of the battery, it is advisable to reduce the current in a stepwise manner as the charging voltage increases. When the voltage reaches 14.4 V, the charging current is reduced by half (3 Amperes for a battery with a capacity of 60 Ah) and at this current the charge is continued until gas evolution begins. When charging batteries that do not have holes for adding water, it is advisable to increase the charging voltage to 15 V and once again reduce the current by half (1.5 A for batteries with a capacity of 60 Ah). The battery is considered fully charged when the charging current and voltage remain unchanged for 1-2 hours. For modern maintenance-free batteries, this state occurs at a voltage of 16.3-16.4 V, depending on the composition of the grid alloys and the purity of the electrolyte (at its normal level).

The temperature of the electrolyte increases during battery charging, so it is necessary to control its value, especially towards the end of the charge. Its value should not exceed 45°C. If the temperature is higher, the charging current should be reduced by half or the charge interrupted for the time required for the electrolyte to cool to 30...35°C.

If at the end of the charge the electrolyte density differs from the norm, it is necessary to make an adjustment by adding distilled water in cases where the density is above the norm, or by adding a sulfuric acid solution with a density of 1.40 g/cm³ when it is below the norm. The density can be adjusted only at the end of the charge, when the density of the electrolyte no longer increases, and due to “boiling”, rapid and complete mixing is ensured. The amount of electrolyte taken and added water or acid solution for each battery can be determined using the data in Table 3. After making the adjustment, continue charging for 30-40 minutes, then measure the density again, and if it differs from the norm, carry it out again.

Table 3. Approximate norms in cm³ for finishing the electrolyte density in a volume of one liter


	1,24			1,25
	Electrolyte suction	Adding solution 1.40 g/cm 3	Adding water	Electrolyte suction	Adding solution 1.40 g/cm 3	Adding water
1,24	-	-	-	60	62	-
1,25	44	-	45	-	-	-
1,26	85	-	88	39	-	40
1,27	122	-	126	78	-	80
1,28	156	-	162	117	-	120
1,29	190	-	200	158	-	162
1,30	-	-	-	-	-	-

Table 3. Continued

Density of electrolyte in battery, g/cm 3	Required density, g/cm 3
	1,26			1,27
	Electrolyte suction	Adding solution 1.40 g/cm 3	Adding water	Electrolyte suction	Adding solution 1.40 g/cm 3	Adding water
1,24	120	125	-	173	175	-
1,25	65	70	-	118	120	-
1,26	-	-	-	65	66	-
1,27	40	-	43	-	-	-
1,28	80	-	86	40	-	43
1,29	123	-	127	75	-	78
1,30	-	-	-	109	-	113

Table 3. Continued

To use the table, its data must be multiplied by the volume of one battery, expressed in liters.
Density of electrolyte in battery, g/cm 3	Required density, g/cm 3
	1,29			1,31
	Electrolyte suction	Adding solution 1.40 g/cm 3	Adding water	Electrolyte suction	Adding solution 1.40 g/cm 3	Adding water
1,24	252	256	-	-	-	-
1,25	215	220	-	-	-	-
1,26	177	180	-	290	294	-
1,27	122	126	-	246	250	-
1,28	63	65	-	198	202	-
1,29	-	-	-	143	146	-
1,30	36	-	38	79	81	-

The operating electrolyte level is set after the density adjustment is completed and no earlier than 30 minutes after the batteries are turned off from charge. If the electrolyte level is below normal, an electrolyte of the same density must be added to the battery.

When charging at a constant voltage, the degree of charge of the battery at the end of charging directly depends on the amount of charging voltage provided by the charger. So, for example, in 24 hours of continuous charging at a voltage of 14.4 V, a completely discharged 12-volt battery will be charged by 75-85%, at a voltage of 15 V - by 85-90%, and at a voltage of 16 V - by 95-97% . You can fully charge a discharged battery within 20-24 hours at a charger voltage of 16.3-16.4 V. At the first moment the current is turned on, its value can reach 40-50 A or more, depending on the internal resistance (capacity) and depth battery discharge. Therefore, the charger is equipped with circuit solutions that limit the maximum charge current. As charging proceeds, the voltage at the battery terminals gradually approaches the voltage of the charger, and the value of the charging current, accordingly, decreases and approaches zero at the end of the charge. This allows charging without human intervention in a fully automatic mode. Erroneously, the criterion for the end of charging in such devices is considered to be the achievement of a voltage at the battery terminals during charging equal to 14.4 ± 0.1 V. In this case, as a rule, a green signal lights up, which serves as an indicator that the specified final voltage has been reached, that is, the end of the charge. However, for a satisfactory (90-95%) charge of modern maintenance-free batteries using similar chargers with a maximum charging voltage of 14.4-14.5 V, it will take about a day.

The accelerated combined charging method is used when it is necessary to fully charge batteries in a shortened time. Accelerated combined charge is carried out in two stages. At the first stage, the batteries are charged at a constant charging voltage, at the second stage - at a constant charging current. The transition to charging batteries at a constant value of the charging current is made when it is reduced at the first stage of charging to a value of 1/10 of the capacity.

Control training cycle

The control and training cycle is carried out to monitor the technical condition of the batteries, check the capacity they provide, and correct lagging batteries. Lagging batteries are those batteries whose parameters are lower than others.

During the control-training cycle the following is carried out:

preliminary full charge;
control (training) discharge with current of 10-hour mode;
final full charge.

A preliminary full charge during CTC is carried out with a charging current equal to 1/10 of the battery capacity. Before the start of the control discharge, the electrolyte temperature should be 18...27°C. The discharge current for batteries must correspond to the value indicated in Table 4.

The constancy of the discharge current must be carefully maintained throughout the entire discharge. The discharge is carried out to a final voltage of 10.2 V. When the voltage drops to 11.1 V, measurements are taken every 15 minutes, and when the voltage drops to 10.5 V, measurements are taken continuously until the end of charging.

The capacity supplied by the battery as a percentage of the nominal value is calculated using. The actual capacity delivered during the control discharge can be either less or more than the nominal one. The final full charge of car batteries is carried out using a normal charging current in compliance with all rules, with the density of the electrolyte adjusted at the end of the charge.

A car battery is a very important element, despite the simplicity of its design, it is fraught with several incomprehensible abbreviations, such as capacity, and of course starting current. I have already written about some, I will write about some more, but today we will talk about the “starting indicators” of the battery - why this is so important and what they should be. Not everyone knows about this parameter and often when choosing a new battery, they initially make a big mistake! And it leads to the fact that the battery quickly fails and cannot start your car in winter...

To begin with, the definition

Battery starting current (sometimes called starter current) - this is the maximum value of the current required to start the engine, namely to power the starter so that it can turn the flywheel with the pistons attached to it. This process is complex, because the pistons compress the fuel (9–13 atmospheres), which enters the chambers. Winter starting is even more difficult, because the oil thickens and the starter needs to overcome not only compression, but also the lack of normal lubrication of the cylinders.

What is the main purpose of a car battery? Of course, the accumulation and subsequent start of the engine, it seems like the structure of many models is the same, but the characteristics are not the same. No, of course, the charged model will have approximately 12.7V, but the current strength and capacity will differ.

A few words about the structure and properties

Batteries were created specifically to recharge and start the car, that is, they are very practical from the point of view of operation. A regular battery discharged very quickly, and it was expensive to change it; that’s when batteries were invented.

Through trial and error, batteries evolved - so a few years after the invention, a very specific model emerged, this was about 100 years ago, which has not changed until now.

Usually these are six compartments with plates made of lead (negative) and its oxide (positive), which are filled with a special electrolyte made of sulfuric acid. It is this combination that makes the battery work; if one component is excluded, the operation will be disrupted. One scattered battery generates an average of 2.1V, this is extremely little to start the engine; in an average battery, they are combined by connecting them in series, usually 6 banks of 2.1V = 12.6 - 12.7V. This voltage is enough to excite the starter winding.

A few words about capacity

However, voltage is only one of the components; it is unified, that is, it is the same for all batteries, regardless of capacity.

But the capacity can differ significantly. It is measured in Amperes per hour, or simply Ah. If we derive a small definition, then this is the ability of a battery to deliver a certain amount of current for an entire hour. Automotive options start at 40 Ah and go up to 150 Ah. However, the most common ones on ordinary foreign cars are 55 – 60 Ah. That is, the battery can deliver 60 Amps for an hour, and then it will be completely discharged. To be honest, this is a big value, if you multiply 12.7 (voltage) and 60 Ah (capacity), you get 762 Watts per hour! You can warm up the electric kettle a couple of times.

We also sorted out the capacitance, now let’s talk directly about the starting current.

So what is this inrush current?

As I already wrote above, the starting current is the maximum current that the battery can deliver in a very short period of time. In simple words, to start the engine of an average car you need approximately 255 - 270 Amperes, a lot! In essence, these are “starting values”, from the word “start” in relation to the power unit.

If the battery capacity is approximately 60 Ah, then this exceeds its nominal value by approximately 4 - 5 times. True, such tension should only be given for about 30 seconds, no more.

Often in the southern regions of our country, where the air temperature always remains in the positive zone, this parameter is not even considered! Because no matter what, we take an average battery, and it will cope with its duties perfectly. After all, it’s warm outside and the oil is liquid. But in the northern regions this indicator is one of the most important, where temperatures are often in the extremely negative zone and it is difficult to start the power unit; the oil looks more like jelly than a flowing liquid. The launch will be extremely difficult.

If to start the engine at “+ 1 + 5” degrees, 200 - 220 Amperes will be enough (at one time), then to start it already at - 10 - 15 degrees, you need to spend 30% more energy, and this is 260 - 270 Amps. Now think about how much energy is wasted at -20 - 30 degrees Celsius.

Thus, the lower the temperature in winter, the more important this parameter is, this is a kind of axiom.

What does the starting current depend on?

If you look at different manufacturers, for example European countries, the USA, Russia or China, then all these batteries will have a different inrush current. So, for example, if you compare 55 Ah China and Europe, the difference can be 30 - 40%! But why is that?

It's all about technology:

The use of purified lead, even in simple acid batteries, will lead to rapid charging and subsequent discharging, and accordingly the starting values will increase.
A larger number of plates in a body of the same dimensions.
More electrolyte.
The plus plates are more porous, which will allow more charge to accumulate.
Hermetic designs do not allow the electrolyte to evaporate, which will allow the battery to always maintain the desired level without exposing the plates.

Of course, you can add build quality and integrity of the manufacturer, all this gives better results than competitors. It’s true that such batteries are more expensive.

But at the moment, there are also new technologies - the record holders for the return of starting current are, their return current can reach up to 1000 Amperes in 30 seconds, about 3 - 4 times more than that of conventional acid options. Although these technologies also have their disadvantages, and first of all this is the price.

It is also worth noting that when starting the engine, the battery voltage drops to approximately 9 Volts, but the current increases many times - this is a normal process. After starting the engine, the voltage will return to its normal level of 12.7 Volts, and the spent charge will be replenished by the car’s generator. If the voltage readings during startup drop to 6 Volts (and take a very long time to recover), then this can be critical; the starter simply does not have enough energy to start. Most likely the battery is failing.

How are measurements taken?

After the battery is produced, it must be tested to determine the starter voltage. Tests in production are complex; batteries are often placed in subzero temperatures, cooled for several hours, and then tried to start the engine.

Usually the tests take place at -18 degrees Celsius and the start-up lasts 30 seconds; if the battery copes, then it can be put into production. If not, change the design, filling, and carry out tests on a new one.

They measure several times, that is, there are a number of intervals with maximum values, during such intervals the maximum currents that this particular instance is capable of producing are measured, they are recorded and later applied to the “sides” of the battery. It should be noted that not all batteries in the batch are tested so strictly. However, “defects” are present, and checks are carried out with a load fork.

In fairness, it is worth noting that earlier in Soviet times, batteries were not filled with electrolyte at all in production (there was a concept of a dry charge), you yourself had to fill and charge them! That is, we buy an electrolyte of the required density, and then charge it for 12 – 24 hours.

What is the starting current of an average battery and what should I do if I buy a larger value?

At the moment there is a division of starting values into gasoline and diesel units. After all, a diesel engine initially needs a higher indicator, because its compression ratio is much higher, can reach up to 20 atmospheres.

SO, the averages:

For gasoline options this is 255 Amperes

For diesel options - at least 300 Amperes

These figures, as they say, were measured at minus 18 degrees Celsius, which may not be enough when starting in severe frosts.

But now, with the development of technology, we can often see starter current indicators in stores of 400, 500 and even 600 Amperes! What happens if you take these numbers? Am I burning my starter?

The answer is simple - of course not. Don't burn it! Take it and forget what a cold start is, with such characteristics you won’t care about any frost.

As for the starter, with a higher current, it will rotate faster and stronger, which will allow it to make more revolutions, and in turn this will contribute to a quick and high-quality start of the engine.

Of course, you need to read the characteristics of your car, but I think a starting value of 450 - 500 AMPERES will be enough for all regions of Russia. Again, I’ll make a reservation, I’m now considering ordinary cars, not trucks, with large and high-volume engines; often even 600 will not be enough for them.

Classification in the world

As I have already touched on a little, in the world there are now several main classifications of inrush current values. Which have their own identification and labeling methods. To begin with, how are they marked:

German manufacturers stand out here - they apply the “DIN” marking
In America they apply “SAE”
In European Union countries (not Germany) they apply “EN”
In Russia they often write “starting or starting current”

The concept of battery capacity

The capacity of the battery is one of its most important technical characteristics. This term is understood as the amount of time that a source of autonomous energy is capable of powering the electrical consumers connected to it. In other words, this is the maximum amount of electricity accumulated by the battery during a full charging cycle. The unit of capacity is Ah (ampere-hour), for small batteries it is mAh (milliamp-hour).

An example of calculating the required capacity

As you know, the calculation of power consumption is made in W, and the battery capacity for a UPS is in Ah. To calculate the required battery capacity to power a particular equipment, it is necessary to make some recalculation. For a better understanding, let's look at a specific example. Let's say there is a 500 W critical load that requires backup for 3 hours. Since the amount of accumulated energy depends not only on the battery capacity, but also on its voltage, to calculate we divide the total power of the redundant equipment by their operating voltage (often confused with the open circuit voltage of a fully charged battery). For a standard 12V battery, the required battery capacity will be:

Q= (P t) / V k

where Q is the required battery capacity, Ah;

V – voltage of each battery, V;

t – reservation time, h;

k is the coefficient of battery capacity utilization (the amount of electrical energy allowed for use by consumers).

The need to introduce a coefficient is due to the possibility of an incomplete charge of the battery. In addition to this, a strong (deep) discharge following a small number of charge and discharge cycles leads to premature wear and failure of the battery. For example, if a new battery is discharged to 30% of its total capacity and then immediately charged, it can withstand about 1000 such cycles. If the discharge value decreases to 70%, the number of these cycles will decrease by approximately 200.

In total, we find that to power this load for the specified period of time it will be necessary:

Q= 500·3/ 12·0.7 = 178.6 Ah.

This is the minimum required battery capacity for the case under consideration. Ideally, it is better to take an energy source with a small reserve (about 20%) so as not to completely discharge it each time - this will help preserve the battery performance for as long as possible.

Q = 178.6 1.2 = 214.3 Ah.

This means that to solve this problem it is necessary to purchase batteries with a total capacity of at least 215 Ah. When using a UPS in conjunction with a generator, it is recommended to reduce the capacitance correction factor to 0.4, since in such a combination batteries are most often used to maintain continuous power supply until the power plant turns on and the entire load is switched to it. Moreover, if the value of the coefficient 0.4 includes the loss of battery capacity during its aging, due to the peculiarities of the pulse converter and others, then on average the discharge of the battery can reach 50% of its nominal capacity.

In the case when several batteries are used to back up the load, the amount of energy accumulated in them is absolutely independent of the type of their connection - parallel, serial, or mixed. Taking into account this feature, it is necessary to substitute the voltage of one battery into the formula for determining the total capacity of batteries, but in this case it is allowed to use only batteries with the same technical characteristics.

Indicators of batteries, with which the concept of capacity is inextricably linked

Dependence of battery capacity on its discharge current.

This dependence is based on the following fact: when the protected load is connected to the battery without using a converter, the amount of current consumed by the battery remains unchanged. In this case, the operating time of connected electrical consumers will be determined as the ratio of the selected capacity to the consumed current. In a more familiar form, this formula is written as follows:

where Q is the battery capacity, Ah (mAh);

T – battery discharge time, hours.

If we are dealing with large amounts of current consumption, then the actual power indicators are often lower than the nominal ones indicated in the passport.

Dependence of battery capacity on energy

Today, it is quite common among users that the capacity of a battery is a value that fully characterizes its electrical energy, accumulated by the battery when it is 100% charged. This statement is not entirely correct. Here it is also necessary to make a reservation that the battery’s ability to accumulate energy directly depends on its voltage and the higher it is, the more energy the battery can accumulate. In fact, electrical energy is defined as the product of the charging current, battery voltage and the flow time of this current:

where W is the energy accumulated by the battery, J;

U – battery voltage, V;

I – constant battery discharge current, A;

T – battery discharge time, hours.

Based on the fact that the product of current and charging time gives us the battery capacity (as discussed above), it turns out that the electrical energy of the battery is found by multiplying the rated voltage of the battery and its capacity:

where W is the energy accumulated by the battery, Wh;

Q – battery capacity, Ah;

U – battery voltage, V.

When several batteries of the same capacity are connected in series, the total indicator of this bundle is equal to the sum of the capacities of all batteries included in its composition. In this case, the energy of the resulting battery pack will be determined as the product of the electricity of one battery and their number.

The concept of battery energy capacity

An equally useful indicator for the consumer of rechargeable batteries is their energy capacity, measured in units such as W/cell. This concept characterizes the battery’s ability for a certain short period of time, which most often is no more than 15 minutes, in constant power mode. This indicator is most widespread in the United States, but has recently been gaining popularity among consumers in many other countries. To approximate the calculation of the battery capacity, measured in Ah based on its energy capacity in W/cell for a period of 15 minutes, use the formula:

W – energy capacity of the battery, W/cell.

The concept of battery reserve capacity

For car batteries, another characteristic is distinguished - reserve capacity, which indicates the battery’s ability to power the electrical equipment of a moving car when the vehicle’s standard generator is not working. This parameter is also better known in the USA and is called “reserve capacity”. It is measured in minutes of battery discharge with a current value of 25 A. To approximate the nominal capacity of the battery based on its reserve capacity indicator, indicated in minutes, you must use the formula:

where Q is the battery capacity, Ah;

T – battery reserve capacity, min.

Battery capacity and charge (charge)

Another fairly popular misconception is the identification of the concepts of battery capacity and its charge (charge). Let's dot the i's. Capacity refers to the maximum potential of a battery, that is, the amount of energy that it can accumulate in a fully charged state. The charge, in turn, represents this energy necessary to power the load in autonomous mode. Hence the conclusion is that the amount of charge of the same battery can be different depending on the charging time of the battery, and the amount of its capacity in the discharged and charged state is the same. Here we can draw an analogy with a glass into which water is poured. The volume of the device will represent the capacity - this is a value that does not depend on whether the glass is full or empty, and the water that is poured is the charge.

What other factors does the battery capacity depend on?

Discharge current

The battery capacity indicators that can be found in their technical documentation and on the product case are indicated by the manufacturer based on the results of test measurements made according to the above formula (Q = I T) at a standard discharge duration (10, 20, 100 hours, etc.). d.). The capacitance is designated accordingly - Q10, Q20 and Q100, as well as the discharge current - I10, I20 I100. In this case, the amount of current flowing through the load with a discharge time of 20 hours will be determined by the formula:

Following this logic, we can assume that during a discharge lasting a quarter of an hour (15 minutes) the current will be equal to Q20 x 4. However, this is not the case, as practice shows; in the case of a 15-minute discharge, the capacity of a standard lead battery will be no more than half of its rated capacity . Accordingly, the value of the parameter I0.25 will be slightly less than Q20 x 2. From here we can conclude that characteristics such as time and discharge current are not proportional to each other.

Final discharge voltage

Each time the battery is discharged, the voltage on it gradually drops, and when the so-called final discharge voltage is reached, it is imperative to disconnect the battery. Moreover, the lower this characteristic, the correspondingly higher the actual battery capacity will be. As a rule, manufacturers indicate on their own batteries the minimum value of the final discharge voltage, which in turn depends on the current used to discharge the battery. There are situations when the voltage of the energy source drops below this value (they forgot to turn off the battery in time or this could not be done because it was impossible to de-energize the load for a long period). Then a phenomenon called deep discharge of the battery occurs. If the battery is often allowed to be deeply discharged, it can quickly fail.

Battery wear

As is generally accepted, a new battery has a nominal capacity (the one indicated by the manufacturer). However, the actual value of this indicator may differ slightly - it may be less than declared due to long-term storage in a warehouse, or after several full charge and discharge cycles and short-term operation in buffer mode, it may increase slightly. Further use of the battery, as well as its storage, invariably leads to physical wear and tear of the energy source, its aging and gradual failure.

Temperature

Such an important factor as the ambient temperature in the place where the battery is used greatly affects the capacity of the latter. If the temperature rises from 20°C to 40°C, the battery capacity increases by 5%, and when it drops to 0°C, it decreases by an average of 15%. A further decrease in air temperature leads to a drop in this parameter by another 25% relative to the nominal value.

How to check battery capacity?

Very often, the owner of a used battery is faced with the task of determining its residual capacity. The classic and, to our credit, the most reliable and effective way to check the actual capacity of a battery is considered to be a test discharge. This term refers to the following procedure. The battery is first fully charged, after which it is discharged with direct current, and the time during which it is completely discharged is measured. After this, the battery capacity is calculated using the already known formula:

For greater calculation accuracy, it is better to select the value of the constant discharge current so that the discharge time is about 10 or 20 hours (this depends on the discharge time at which the nominal battery capacity was calculated by the manufacturer). Then the obtained data is compared with the passport data, and if the residual capacity is 70-80% less than the nominal capacity, the battery must be replaced, since this is a clear sign of severe wear of the battery and its further wear will occur at an accelerated pace.

The main disadvantages of this method are the complexity and labor-intensive implementation, as well as the need to remove batteries from service for a fairly long period of time. Today, most devices that use rechargeable batteries for their operation have a self-diagnosis function - a quick (in just a couple of seconds) check of the condition and performance of energy sources, but the accuracy of such measurements is not always high.

This question is periodically asked by customers who buy wheel motors, accessories and batteries for their own conversion of bicycles to electric traction. At first glance, it may seem that there are no current limits in electronic kits and you need to introduce them yourself. Actually this is not true.

Both lead-acid and lithium-ion batteries can briefly withstand maximum currents of up to 10s without destruction - that is, a discharge current that is 10 times their rated capacity. For example, lead-acid batteries with a capacity of 12 amp hours can be loaded with a current of 120 amps for a short time, and lithium-ion batteries with a capacity of 10 amp hours can briefly supply a current of 100 amps.

However, for constant loads these values must be reduced by at least 2 times, that is, to 5s. In Volta bikes lithium batteries, this limitation is implemented in an electronic safety circuit built into the battery. It limits the discharge current to a safe value of 5s, and the voltage to 30 volts. When the load is exceeded or the voltage drops below set limits, the circuit disconnects the battery from the wheel motor, thereby protecting it and ensuring an estimated service life of about 5 years.

Lead-acid batteries do not have such a circuit. Here, the maximum discharge current is limited by the controller itself - to the maximum value specified in its characteristics. When the voltage drops below 10.5 volts (based on one lead-acid battery), Volta bikes controllers also disconnect the batteries from the wheel motor to prevent sulfation and destruction. In addition, the electric bicycle circuit must contain a fuse or circuit breaker, which serves as protection not only from short circuits, but also from overloads. When converting a bicycle to electric power yourself, we recommend installing a 20-amp circuit breaker.

Thus, it will not work to accidentally or even intentionally go beyond the safe operating conditions of lead-acid or lithium Volta bikes batteries. Another question is that a completely discharged battery of any kind should be charged as quickly as possible and, in any case, it is categorically not recommended to leave an electric bike with discharged batteries for the winter somewhere in the garage. Such actions lead to rapid failure of all types of batteries for electric vehicles.

Another misconception is that batteries need to be charged only after a complete discharge - thus, supposedly, the maximum number of charge-discharge cycles specified in the technical specifications is ensured. Think about it: if you do this with the battery of your own car - for example, drive with a faulty generator, and charge the battery at home, after trips, from a charger, then in this mode of operation the starter battery will last at best 2-3 months.

And gel lead-acid batteries for electric bikes, and AGM batteries too, differ from starter batteries only in that their electrodes are thicker and they are better fixed in the case to prevent the active mass from shedding. Therefore, they should be recharged as often as possible - after each trip. The same applies to lithium-ion batteries for electric bikes.

As for high discharge currents, it should be remembered that the higher the discharge current, the faster it will completely discharge the batteries of an electric bicycle or electric scooter. Current with a constant load of 1s will discharge high-quality batteries of any type in 1 hour; current 2s - in half an hour, and 4s - in just 15 minutes. Where can you get to with such electricity consumption?

Therefore we recommend:
Firstly, use electricity sparingly if you need to increase the driving distance (please read the article on this topic), secondly, if the batteries run out in less than 50-60 minutes under standard travel modes for you, this is a reason to think about replacing them with more powerful ones.