What is Car Battery Bubbling?

Car battery bubbling is when excess electricity disintegrates the electrolyte in every cell, making the battery off-gas. This happens when the charging amperage exceeds the natural absorption rate, making the battery overheat, and the electrolyte bubbles developing a flammable hydrogen gas. A bubbling battery is being overcharged and can damage it.

Causes of battery bubbling


The alternator in your car charges the battery continuously as you drive. The alternator which overcharges the battery can result in a bubbling process. Most car batteries have an optimum charging voltage of 14 volts. If the voltage rises above 14.5V, your battery will end up overheating and bubbling, resulting in severe battery damage. Too many amps or volts can cause this.

Ventilation issue

All lead-acid car batteries are equipped with vents. The ventilation ducts service purposes such as:

  • Protecting penetration of flammable substance unto the battery when ignited by hydrogen

  • Condensing and returning the evaporating water

  • Removal of accumulated gases

To achieve such goals, the ventilation duct has been designed into a maze. During summer seasons, overpressure forms in the car battery and drops in portions accompanied by an antifreeze release. Therefore, it also a flame arrester which refers to a breathable layer of combustible material.

Short circuit

If a short circuit happens in the banks of your battery, the current load on the undamaged sections can significantly increase. In most cases, such a battery will bubble after you connect a charger.

One of the main signs that you can use to diagnose that battery is bubbling because of short-circuiting is by considering when only a few banks are bubbling.

For instance, the output voltage might drop to 10.5 instead of the expected 12.6. consequently, the generator voltage might be greater than the charge parameter resulting in the electrolyte’s bubbling. The following are the causes of battery short-circuiting:

  • Damaged plate active mass accumulates at the bottom of the case resulting in the bridging of the plates.

  • A separator envelope broke and led to the bridging of the positive and negative plates.

  • The electrodes broke from the connecting bridge.

Errors in the operation

Errors in operation can happen if you include headlights, a radio tape recorder, heating, and other powerful current consumers with a muffled engine. Consequently, your battery will be discharged, and when you attempt to start your engine, the battery will begin to bubble.

The main reason is that a discharged battery experiences a lot of current than a charged one. That is why you are supposed to apply a recharging current of 10 percent of the nominal parameter.

Further, some people make the mistake of installing two batteries on their buses and trucks. In such a case, the mistake is on the mismatch of the capacities for the batteries. Typically, an identical current will flow to every battery during the charging process. Consequently, a bubbling situation might arise when one battery already charged fully and the other one had not charged.

Reload in battery

If you supply a higher voltage to the battery terminals than the manufacturer’s recommended, the electrolyte starts to bubble. Such a case can happen because of using improvised devices to charge a battery pr improper factory memory setting.

Apart from that, you might incorrectly set the current strength, which is supposed to be exactly 10 percent of your battery capacity. For instance, if the battery capacity is 50Ah, its current should be 5 Amps. If you overestimate that value, the battery liquid can start to bubble.

How car bubbling affects your battery

Constantly bubbling of the electrolyte when charging can contribute to the following undesirable battery conditions and processes:

  • Corrosion of clamps and terminals of the charger.

  • Battery explosion

  • Closing the plates together

  • Destruction of lead plates, power loss

The most serious damages of bubbling is a battery explosion. That is because a battery explosion can increase the possibility of having a fire due to chemical burns arising from a spill of a great deal of sulfuric acid solutions.


You can solve the bubbling of the battery by turning off the electric current supply. Suppose the cause of the battery generation in the battery is an incorrect voltage or current level. In that case, you can set them within the recommended limits to prevent the bubbling of the electrolyte.

If your car bubbles it does not charge, it might be a sign of an end-to-charge cycle. You can disconnect the charger and install it on your car to observe its polarity in such a case. If the batter begins to bubble immediately, you might need to replace it. In reality, the lead-acid car battery has a limited lifespan because its plates are broken, or the sulfation is very strong, and you cannot restore it.

If the issue lies with the battery, such as short-circuiting, you can change your battery. If the new generator fails and it still has its warranty, you can consider exchanging it. If the guarantee has expired, you can purchase a new device because it can be pointless and challenging to restore an old battery.

How to charge your car or RV battery effectively

Turn off all parts

It is critical to shut everything, including the electrical features and interior and exterior lights in your car. If you leave them, your battery can drain while charging it. Other car models need you to remove the battery terminals before charging the battery to avoid damaging the electrical parts.

Set charge rate

You need to set the charge rate before connecting the battery to a charger. Normally, the charge rate ranges between 2 to 10 amps. You might want to charge the battery at its lowest settings. Undertaking a slow charge will ensure that you do not overcharge the battery and remain in good condition. The only you can fast charge the battery is when you wish to use it immediately. Although a fast charge setting can help get back on the road after a short period, it can significantly minimize the battery life.

Clean the battery terminals

You need to identify the negative and positive battery terminals. You can remove the plastic cover from the positive terminal and use a wire brush to clean any corrosion.

However, if you cannot remove the corrosion using a brush, you can use baking soda paste. When you clean the car battery, you ensure that it has a better connection with the charger.

Connect the charger

Place the battery charger in a location where it is secure. You can connect the red cable clamp to the positive terminals and do the same with the black cable onto the negative terminals. After you can connect the charger, you can turn it on.

Charge and test

Leave the battery to charge fully. After the battery is charged, you can remove the clips, connect the battery terminals caps, and start your car.



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