Why does the battery boil on the car

Бывалые автолюбители, использующие отечественные и иностранные машины, часто встречались с закипанием аккумуляторной батареи. Подобная ситуация может застать любого водителя как вдалеке от дома, так и во время непродолжительной поездки. Разберемся, why does the battery boil on the car и как себя нужно вести в такой ситуации.


  • 1 Boil the appliance
  • 2 Symptoms that precede the boil
  • 3 Recharging the battery
  • 4 Problem generator

Electric appliance boil

An undesirable boiling procedure causes the battery to have the same consequences as intensive battery operation. It is considered to be that in an hour of problematic electrolyte boiling in the banks practically the same processes occur as during its three-day continuous operation.

During this procedure, a humid environment is formed in the engine compartment. Such events accelerate corrosion processes with metallic elements. Uncoated or thin metal elements are particularly affected.

for what reasons does the battery boil on the car

The situation is aggravated by the possible spraying of electrolyte, which basically has a sufficient concentration of aggressive acid. A chemical compound, getting on the metal, plastic, rubber or other substances quickly reacts with them, destroying their integrity.

The caustic composition also destroys the paintwork.applied to the car body. Penetrating into the cracks, aggressive environment gets to the metal base. Therefore, when the battery is boiling while driving, you need to minimize the consequences as quickly as possible.

Symptoms that precede the boil

Having discovered earlier boiling, the driver will be more able to secure his car. But to do the check all the time, there will hardly be any motorists, therefore It is worth paying attention to indirect signs. The specific smell of electrolyte should alert any car enthusiast. Especially it will become noticeable in problem cars after a long move.

In other cases, pay attention to your battery and check it for boiling will be needed in the following situations:

  • insufficient level of illumination of the dashboard;
  • the starter often fails the first time;
  • the engine "sneezes" during startup.
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why does the battery boil on the car

Although the symptoms are similar to a discharged battery, it is worth raising the hood and checking the battery area for the appearance of puddles contaminated with spots (the electrolyte easily attracts dust). Such visual signs indicate a problem.

You can self-diagnose even on the road. After traveling for 20 ... 30 minutes, the driver does not jam the engine, but stops and, lifting the hood, carefully unscrews the plugs in the battery. If gas bubbles become noticeable, then unpleasant fears were confirmed.

In no case do not use a lighter or other open fire for lighting in the engine compartment.

Основными причинами, why does the battery boil on the car, является короткое замыкание или перезаряд батареи. Рассмотрим оба случая подробнее.

Battery recharge

When an estimated voltage is exceeded in a battery, the water in the electrolyte composition begins to decompose into separate components: hydrogen and oxygen. Both gas tend to leave the space banks, leaving the surface. The process is very similar to the usual boiling of water on the stove (although it has a different nature) and therefore deserved this name.

To check you will need a special tester. It is thrown over the battery terminals, and then receive data in two positions:

  • at idle;
  • during loading of the power plant to 2000 ... 2500 rpm.

The second parameter is controlled by the automobile tachometer.

why does the battery boil on the car

When receiving values ​​in the range of 12.8 ... 13.4 V on the tester, the battery is considered working. A slight excess of the readings in some batteries up to 14.3 V.

The main cause of this result is a problem voltage relay. It requires replacement. For testing, additional testing is carried out:

  • on the brushes of the regulator a powerful 12 V lamp is placed;
  • to the conclusions of the relay summing "+" from the battery;
  • on the relay we throw "-" from the battery, and as a result the lamp should light up, otherwise there was a break of contacts.
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If a finger battery is inserted in series in the circuit, then the lamp must go out, because the voltage increases. The faded light signals a blown relay.

It is necessary to take into account that the relay works according to the electromechanical principle, therefore it may have knocked down settings. For purely electronic devices, only a complete replacement is left.

Problem generator

If boiling battery is detected in the car, then you need to check the performance of the diode bridge in the generator. It converts alternating voltage into direct current. If a one of the diodes can not cope with their duties or burned out, the consequences are noticeable:

  • the charge is not supplied to the battery;
  • there is a forced discharge of the battery;
  • AC is supplied to the battery, leading to boiling of the electrolyte.

why does the battery boil while driving

If the incoming voltage is within the normal range, and the battery continues to boil, then the reason is often covered by the battery itself. Probably, a short circuit occurred in one of its cans, while for the rest the allowable voltage with which they can not cope is exceeded. The consequence of these events is boiling and decomposition into hydrogen and oxygen. Repair the short-circuited battery is not subject. Will need a new power source for the car.