How to determine the polarity of a car battery

Direct and reverse polarity of the battery - what it means and what is the difference

For a car, the battery is the most important element. It ensures a confident start of the internal combustion engine, powers electronic components and pre-installed devices. To ensure this process, the battery must be connected to the on-board network using pole terminals. The latter are located on the lid of the sealed housing. One of the terminals is marked “-”, and the other “+”. The battery is also charged using the terminals. The main thing when connecting and recharging is not to mix up the polarity terminals, and this requires knowledge of the polarity of the batteries. Let's find out what battery polarity is, how to determine it, and what it is.

What is polarity?

Polarity is a concept that defines the location of the pole terminals (external current-carrying elements) on the cover or front side of the battery. There are two standard position types:

But the current leads can be located differently. Such “exotic” batteries have not caught on with car owners in Europe and the CIS countries, so they are extremely rare on store shelves. It remains to find out what the polarity of the battery is, direct or reverse, and whether there is a difference between the batteries.

Straight battery polarity

Batteries of this type were developed by Soviet engineers. All cars produced in the USSR were equipped with direct-type batteries. They are characterized by the following arrangement of pole terminals - “+” on the left and “-” on the right. Batteries are still produced with this arrangement of current leads today. A fairly impressive percentage of vehicles of foreign brands that are assembled in the CIS countries are equipped with a battery with a left “+”.

Reverse battery polarity

Reverse polarity batteries are manufactured by manufacturers in European countries. Therefore, all imported vehicles are equipped with batteries in which the current terminals are located exactly the opposite - “+” on the right and “-” on the left.

How are batteries different?

How to identify forward and reverse polarity?

Determining the polarity of a product is not difficult. You need to turn the battery so that the front side is facing you. The front side is:

• where the label with characteristics is pasted;
• in which the location of the pole terminals will be closest to the viewer;
• where identification marks and markings are applied.

In most cases, the pole terminals are labeled “+” and “-” directly on the body. If, when you turn the battery towards you, the positive terminal is located on the left, then it is a battery with straight polarity. If there is a “-” on the left, it means the opposite. The marks are generally accepted designations, but they may not be on the body. Equipment manufacturers often use their own markings. For example, pole terminals are distinguished by color. Positive is marked with a red cap, negative with black or blue.

There are also other designations:

• reverse polarity - “0” or “R”;
• straight polarity - “1” or “L”.

Having figured out what the difference is between direct and reverse battery polarity, it will not be difficult to remember the generally accepted symbols. They are valid for batteries produced for passenger cars. When determining the type of battery for buses, trucks and any other heavy equipment that uses batteries with a capacity of 110 Ah or more, the designations will be different:

• the left “+” indicates equipment for European special equipment - reverse polarity;
• the right “+” indicates equipment for Russian special equipment - straight polarity.

Also, when purchasing a battery, you need to take into account differences in the production of cases. Asian battery manufacturers place the pole terminals so that they protrude well above the surface of the top cover. Most European companies make the case more ergonomic, that is, they recess the terminals. Asian devices have significantly smaller terminal diameters than European ones. For comparison, Asia/Europe - “+” output 12.7 mm/19.5mm and “-” output 11.1 mm/17.9 mm.

Is it possible to set a different polarity?

Theoretically it is possible. But, as stated above, this can lead to unnecessary waste of money and additional hassle with placement in the socket, the length of the wires, and mismatched terminal diameters. It's another matter if you connect the new battery incorrectly. This can lead to serious consequences. Therefore, if the technical documentation indicates that the car requires straight polarity of the battery, it is wiser to buy a battery with straight polarity.

What will be the consequences if the polarity is reversed when connecting?

• generator breakdown;
• overheating of the diode bridge;
• failure of diodes (accompanied by a pop when the case is destroyed, a smell);
• failure of on-board electronics;

Important! Most electronic devices have reverse polarity protection.

But not powerful consumers of electric current - amplifiers, radio tape recorders. They contain elements, such as capacitors, that are extremely sensitive to polarity reversal. Their failure is guaranteed due to heating. Initially, as the temperature rises, the capacitor will swell and then explode. The process will be accompanied by a characteristic sound and smell.

• failure of the relay in the wiring;
• short circuits in the network, etc.

When lighting a cigarette, the reverse and direct polarity of the battery is also extremely important, as described above. Incorrect connection of the battery terminals will cause just as many problems for the donor. First of all, it will cause an instantaneous short circuit with a voltage of 24 V. In the best case (if the terminal wires have a sufficient cross-section - at least 16 mm2), the connecting wires will heat up and melt, in the worst case, the driver will get a burn on his hands. An increase in temperature can only mean one thing - incorrect placement of the clamps.

Therefore, lighting is performed according to the following scheme:

• The crocodile terminal is attached to the positive terminal of the car being lit;
• The crocodile terminal is attached to the positive terminal of the donor battery;
• The crocodile terminal is attached to the negative terminal of the donor battery;
• The crocodile terminal is installed on the negative terminal of the car being lit.

Important! When installing the clamps, pay attention to the color marking of the wires. Connect “+” with “+”, and “-” with “-”, or red with red, and blue (black, green) with blue.

Changing battery polarity

Algorithm for reversing battery polarity:

• discharge the battery to “0” - attach some load to the terminal;
• reconnect the negative wire to the positive terminal, and the positive wire to the negative terminal;
• charge the battery;

Important! If everything is done correctly, the device will begin to actively take charge. In the process, the temperature will increase, and significantly. This is normal and indicates the beginning of the conversion of "+" to "-", "-" to "+". The plates inside the cans also change.

• turn off the unit when the cans boil.

This procedure is fraught with consequences. Especially if the battery is not of high quality. Cheap devices use very thin lead and dioxide plates. Their thickness is slightly larger than foil. They will not withstand sulfation and will collapse. You should not carry out a polarity reversal without checking the characteristics of the battery if it has already been used. You need to check whether the electrolyte inside the compartments is cloudy, whether there are any closed cans, and whether the device has sufficient density. If there are any problems with the battery, then it will not withstand the procedure. Therefore, in order not to waste money and not expose yourself to car danger, it is wiser to understand the concept of battery polarity and buy those recommended by the car manufacturer.

How to determine the polarity of a car battery

Car batteries have a characteristic called polarity. And when choosing a new battery, it is very important to correctly determine the correct polarity. Otherwise, you may have problems installing it. In this article we will talk about how to determine the polarity of a car battery.

The most common layouts of current leads are direct and reverse polarity. There are also very exotic options for the location of current-carrying elements, but they have not taken root on the Russian market. An error in choosing the polarity will not allow the battery to be used for its intended purpose - the current-receiving pole wires, most likely, simply will not reach the corresponding terminals. Therefore, before purchasing a new battery, it is better to check what polarity your current battery has. This way you can quickly navigate and avoid mistakes.

Although this situation is not catastrophic. If you have a receipt on hand (or a product passport with a stamp from a trading organization), then in the store you can easily exchange the purchased battery for one that fully meets the required criteria. But this whole procedure takes a lot of time and mental strength, and besides, there are different situations: the retail outlet is closed for re-registration, the seller did not come to work for one reason or another... How can I exchange a battery purchased in an online store? Of course, in this case, the law obliges you to return or exchange the goods, but this will take much more time.

Therefore, it’s easier to just determine and remember the polarity type of the battery in your car just once. This is very easy to do. On batteries with a capacity of up to 110 Ah, the current leads are located on the long side. Place the battery with this side facing you. The “+” and “-” symbols should be located on the terminals or next to them, indicating the corresponding poles. If the positive terminal is on the right (usually it is slightly thicker than the negative terminal), then this is a battery with reverse polarity. And if the “plus” is on the left, then you have a battery with straight polarity.

Direct and reverse polarity of a car battery

Domestic passenger cars (as well as most cars of foreign brands, whose assembly is carried out in Russia) are equipped with batteries with straight polarity. Foreign cars assembled in other countries have batteries with reverse polarity.

Real photo of batteries for passenger cars with direct and reverse polarity

Determining the polarity of batteries for trucks occurs in a similar way. We turn the battery with the side with the current leads away from us (on cargo batteries this is the short side) and look where the plus and where the minus are. If the positive terminal is on the right, then this is the so-called reverse or European polarity. If the positive terminal is on the left, then this is direct or Russian polarity.

On the left is European or reverse polarity, on the right is Russian or direct polarity

If you examined your battery, but you were unable to determine where your “Plus” and “Minus” are, then you can pay attention to the thickness of the current carrying terminals. On most batteries used in Europe and Russia, the thickness of the current carrying elements is set by a single standard - at the positive terminal it is 19.5 mm, and at the negative terminal it is 17.9 mm. The difference between them is noticeable to the naked eye; the positive terminal is noticeably thicker. But, there are also batteries with thin terminals. Their positive terminal thickness is 12.7 mm, and the negative terminal is 11.1 mm.

Video about determining battery polarity

Determining battery polarity

Car batteries have two types of polarity: forward and reverse. Sometimes battery sellers will say "right-side positive battery" or "left-side positive battery." In all these cases, we are talking about the location of the positive and negative terminals of the battery (pole terminals).

To correctly determine the polarity of a battery in a passenger car , it must be turned towards you, as in the figure:

Directly on the terminals, or next to them, there must be “+” and “-” icons, which indicate the poles.

1. If the plus is on the right , then it is a reverse polarity battery. It may also be called “euro polarity” or denoted “0” or “R”.
2. If the plus is on the left , then this is direct polarity. It may also be called “standard”, “1” or “L”.

As a rule, domestic passenger cars are equipped with batteries that have straight polarity. On foreign cars, reverse polarity is used.

The situation is completely different with the polarity of batteries for trucks, buses, construction and special equipment with a capacity of more than 110 Ah:

• “3” - “+” on the left (euro, reverse). For European trucks.
• “4” - “+” on the right (standard, straight). For Russian trucks.

Another feature of the battery is the design of the housing. There are two main ones:

- for Asian cars (Chinese, Korean, Japanese, some American). Their terminals protrude above the housing cover. They are higher than European batteries.

- for European cars. The terminals are recessed into the battery cover. They are lower than Asian batteries.

A few words about caring for battery terminals.

Caring for the battery pole terminals comes down to identifying and destroying traces of corrosion. Traces of corrosion appear as white or yellowish powdery deposits.

To process the terminals you need:

1. Remove the battery from the car.
2. Treat the battery terminals with a solution of water and soda.
3. A reaction will begin with the formation of bubbles. The leads will turn brown.
4. If necessary, clean the terminals with a wire brush.
5. After the reaction is complete, wipe the pole terminals and the battery itself with a cloth soaked in cold water and dry the battery.
6. Place the battery into the socket on the car.
7. Apply a thin layer of Vaseline to the terminals and terminals. This will prevent further corrosion.
8. With the ignition off, connect the wires to the battery terminals.

Battery polarity – reverse or straight. How to determine polarity?

In comparison: 0

The battery is the main source of electric current in a car, the main characteristics of which are the rated capacity and the cold start current supplied to the starter. However, there is one more characteristic that is very important when choosing a battery model - its polarity , i.e. location of external current leads (current carrying elements “+” and “-”) on the front panels of the battery.

The fact is that the modern range of batteries is represented by models of domestic and European production and two main polarity options - direct and reverse (other options are extremely rare and are not used in the Russian Federation). What is the difference between them, and why is it important to choose a battery with the correct polarity to meet the vehicle's technical requirements?

It should be understood that different polarities of batteries do not affect their performance in any way - batteries with direct and reverse polarity work absolutely identically. The only difference is in the geometry of the current leads (left-right) and restrictions on use - batteries with direct polarity are used in domestic cars, and reverse polarity is typical for batteries in European and American cars. These differences must be taken into account when connecting the battery to the starter terminals on the car.

Straight polarity

Russian (straight) polarity of the battery is marked with the number “1” and is suitable for most cars of the domestic automobile industry (except for some latest generation models and export versions). In such batteries, on the front panel the positive terminal is on the left, and the negative terminal is on the right. To eliminate connection errors, the current terminals on the battery case are usually marked with “+” and “-” symbols.

Reverse polarity

European (reverse) polarity is an almost complete range of European, Japanese, Korean and American cars. Batteries with reverse polarity are marked with a “0” . In them, the positive terminal will be on the front panel on the right, and the negative terminal on the left.

There are also batteries with a diagonal arrangement of current leads (marked with the symbol “2” ), as well as European batteries for trucks with reverse lateral polarity ( “3” ), and domestic batteries for trucks ( “4” ) with direct lateral polarity.

To avoid mistakes when connecting them, you should carefully monitor the digital markings of battery models. Why is it important?

Sometimes even an experienced driver can mistakenly buy a battery with the wrong polarity for the car or connect the terminals to the battery incorrectly: externally and in terms of technical characteristics, batteries with direct and reverse polarity may be no different.

At the same time, incorrect connection of polarities is dangerous for the car with many unpleasant consequences: rapid battery discharge, short circuit (fuses burn), ignition of electrical wiring, destruction of the battery itself, failure of the ECU (on-board computer) or generator, blown fuses of the battery, car lighting system , alarms and stoves. If the battery is incorrectly connected to the charger, the charger will burn out, and when recharging one battery from another (“lighting up”), both batteries and even both cars can burn out.

Self-determination of polarity

If the battery number markings and current terminal symbols (“+” and “-”) are missing on the battery case, use a tester (multimeter or voltmeter) that will accurately determine the polarity of the battery current terminals. A device connected to the current terminals with probes will show the presence of positive voltage if connected correctly, and negative voltage if connected incorrectly.

In addition, on most battery models, the positive contact is most often marked in red (usually this marking is practically not erased), and its size is usually larger than that of the negative current terminal. It should be remembered that for some models of American-made batteries, these methods of determining polarity do not work: the battery itself simply does not have current terminal pins (instead there are recesses for contacts).

Using batteries with inappropriate polarity

If you mistakenly bought a battery with a polarity that does not meet the technical requirements of your car, then theoretically such a battery can be used (although undesirable) by turning it the other way into the socket under the hood. But you run the risk of running out of length on one of the terminal cables, which will have to be extended with starting wires.

Experts do not recommend doing this, as you can make a mistake in calculating the cable cross-section and burn out all the electrics on the car. It’s easier to change the battery from the seller, or even better – figure out the polarity of the car in advance and, when purchasing, immediately order the battery recommended by the car manufacturer.

What is the polarity of a car battery and how to determine it?

When choosing a battery, you must pay attention to a number of parameters. Among the main ones, it is worth noting the nominal capacity, housing size, starter current and polarity. Today we will talk about the polarity of a car battery and how to determine it. This is one of the key parameters of the battery. If you choose the wrong polarity, you simply will not be able to connect the battery to the car and start using it.

Why is it necessary to know the polarity of a car battery?

Polarity is a characteristic of a car battery that determines the location of its external terminals. If you buy a car battery with the wrong polarity, you will have problems with its installation and connection.

The fact is that the mounting niche for the battery allows you to install it in one position. If the polarity is inappropriate, then the length of the wires with terminals is simply not enough to connect them to the corresponding terminals of the battery. That is, you simply will not be able to use the battery.

Types of battery polarity

Manufacturers produce batteries with six types of polarity. They differ in the layout and integration of battery elements. The most common of these are four types of polarity. Two types are used in batteries for passenger cars and two more for trucks.

Batteries for passenger cars

Before determining the polarity of the car battery, turn it towards you (with the sticker). The battery terminals will be on the top of the battery on the side closest to you. Now we look at the location of the positive (+) and negative (terminal) on the battery. There are two options:

1) The positive current lead is on the right, and the negative lead is on the left. This is reverse polarity or European. It is also designated as “0”. The image below shows a top view of a car battery.

Reverse polarity of car battery

Straight polarity of car battery

Here it is also worth saying about the mythical “Asian” and “American” polarities. These do not exist in nature. There are Asian and American battery sizes. Asian type batteries are slightly smaller in width than European ones, and slightly larger in height. Additionally, they do not have a “step” on the top lid. The terminals of Asian batteries may be thinner, and in some cases they are made for different fastenings.

American-type batteries differ in the type of current leads and their location. The conclusions are not on the top plane, but on the side. They are made for bolt fastening. Although there are models that have pins on the side surface, and standard ones on the top cover.

Batteries for trucks

On most truck batteries, the current leads are located on one of the short sides of the battery. To determine the polarity of a car battery, turn the battery towards you with the side with the leads and look at their location. There are also two options here:

1) The positive terminal is on the left, and the negative terminal is on the right. This is the polarity of the car battery, reverse or European. It is designated by the number “3”.

Reverse polarity of cargo battery

Straight polarity of the cargo battery

Cargo batteries can be found in a configuration designated by the number “2”. In this case, the battery current terminals are located diagonally on the upper side.

Diagonal pin arrangement

Other types of polarity

There are two more less common types of battery layout, designated by the numbers “6” and “9”. They are shown in the images below.

How to determine polarity in the absence of pin markings?

It happens that you need to determine the polarity of car batteries that do not have terminal markings. As a rule, this problem does not exist, since battery manufacturers mark the terminals with “+” and “-” signs. They are often additionally highlighted with flowers. Positive is red, and negative is black or blue. But suppose there is no marking. What to do then?

We offer you 4 different ways to determine the polarity of the terminals:

• Diameter of current leads. The simplest option is to measure the diameter of the battery terminals. Positive leads always have a larger diameter than negative ones. To be more precise, with a European standard size, the positive current lead has a diameter of 19.5 mm, and the negative one has a diameter of 17.9 mm. For an Asian-sized battery, these values ​​are 12.7 and 11.1 millimeters. You can use a caliper to measure the diameter;
• Lemon acid. In principle, you can take a weak solution of any other acid. Screw copper wires to the battery terminals, and lower their other bare ends into an acid solution. They shouldn't touch each other. Where rapid gas evolution will be observed, there is a negative current lead;
• Raw potatoes. In this case, copper wires are stuck into the cut of the potato. The distance between them is from 5 to 10 millimeters. Around the wire from the positive terminal the potatoes will turn green;
• Multimeter. Take a multimeter and turn it on to measure voltage. Touch the battery terminals with the probes and watch the readings. If the voltage has a plus sign, then under the red probe you will see a “+” terminal, and under the black “-”. If the voltage has a minus sign, then vice versa. Under the red probe there is a “-” pin, under the black probe there is a “+”.

Now you know how to determine the polarity of a car battery yourself. If you still have questions, ask them in the comments. And don’t hesitate to ask consultants in stores about the battery characteristics. They are required to know them all and advise you. Enjoy the shopping!

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