Battery polarity direct or reverse

If this is your first time buying a battery for your car, you may be confused by the seller's question about battery polarity. What is polarity anyway? How to define it? What happens if you buy a battery with the wrong polarity? We will try to answer these questions in our today's article on the Vodi.su portal.

Forward and reverse battery polarity

As you know, the battery is installed in its strictly defined seat under the hood, which is also called the nest. In the upper part of the battery there are two current terminals - positive and negative, a corresponding wire is connected to each of them. So that motorists do not accidentally mix up the terminals, the length of the wire allows you to reach it only to the corresponding current terminal on the battery. Moreover, the positive terminal is thicker than the negative one, this can be seen even by eye, respectively, it is almost impossible to make a mistake when connecting the battery.

Thus, polarity is one of the characteristics of the battery, which indicates the location of the current-carrying electrodes. There are several types of it, but only two of them are most widely used:

direct, "Russian", "left plus";
reverse "European", "right plus".

That is, batteries with direct polarity are mainly used on domestic-made machines developed in Russia. For foreign cars, they buy batteries with reverse euro polarity.

How to determine battery polarity?

The easiest way is to carefully look at the sticker on the front and make out the markings:

if you see the type designation: 12V 64 Ah 590A (EN), then this is the European polarity;
if there is no EN in brackets, then we are dealing with a conventional battery with a left plus.

It is worth noting that the polarity is usually indicated only on those batteries that are sold in Russia and the former republics of the USSR, while in the West all batteries come with European polarity, so it is not indicated separately. True, in the same USA, France, and in Russia as well, one can see in the markings such designations as “J”, “JS”, “Asia”, but they have nothing to do with polarity, but only say that before us a battery with thinner terminals especially for Japanese or Korean cars.

Battery polarity straight or reverse

If it is not possible to determine the polarity by marking, there is another way:

we put the battery towards us with the front side, that is, the one where the sticker is located;
if the positive terminal is on the left, then this is direct polarity;
if plus on the right - European.

If you choose a battery of type 6ST-140 Ah and above, then it has the shape of an elongated rectangle and the current leads are located on one of its narrow sides. In this case, turn it with the terminals away from you: “+” on the right means European polarity, “+” on the left means Russian.

Well, if we assume that the battery is old and it is impossible to make out any marks on it, then you can understand where is the plus and where is the minus by measuring the thickness of the terminals with a caliper:

the plus thickness will be 19,5 mm;
minus - 17,9.

In Asian batteries, the thickness of the plus is 12,7 mm, and the minus is 11,1 mm.

Battery polarity straight or reverse

Is it possible to install batteries with a different polarity?

The answer to this question is simple - you can. But the wires must be connected correctly. From our own experience, let's say that on most cars that we dealt with, the positive wire is enough without problems. The negative one will have to be increased. To do this, you will have to remove the insulation and attach an additional piece of wire using the terminal.

On many more modern cars, there is practically no free space under the hood, so there may be problems with building up the wire, there will simply be nowhere to place it. In this case, a new battery without damage can be returned to the store within 14 days. Well, or with someone to change.

If you mix up the terminals when connecting

The consequences can be very different. The easiest consequence is that the fuses that protect the on-board network from short circuits will blow. The worst thing is a fire that will occur due to the melting of the wire braid and sparking. It is worth noting that for a fire to start, the battery must be in the wrong connected state for a long time.

Battery polarity straight or reverse

"Battery polarity reversal" is an interesting phenomenon, thanks to which nothing can threaten your car, the battery poles will simply change places if connected incorrectly. However, this requires the battery to be new or at least in good condition. Nevertheless, polarity reversal is harmful to the battery itself, since the plates will quickly crumble and no one will accept this battery from you under warranty.

If you monitor the technical condition of the car, then a short-term incorrect connection of the battery will not lead to any catastrophic consequences, since the computer, generator, and all other systems are protected by fuses.