Why is that car battery needs constant filling of water ?

Question

Battries used in Cars/ buses / lorries need refilling of water. What is the actual purpose of this??

Answer 1

The act of charging a lead/acid battery generates hydrogen vapor and causes the battery to heat up slightly. Even a "sealed" battery still has to be vented to prevent exposive buildup of gases. Due to the heat some water vapor is also lost in the process, so eventually the battery needs to be topped off with pure water. Modern "sealed" batteries just have a very small vent tube that minimizes the loss of water vapor, so it lasts longer before needing water. If you fail to add water, eventually the plates in the battery become uncovered and battery capacity is lost - very slowly until eventually it won't hold enough charge to start the car.

Answer 2

The water used in wet cell batteries is part of the process of storing the electricity needed to run the vehicle. As the battery is charged by the generator/ alternator. The water is heated up as part of the process. Some is even boiled off. And that is the water that is replaced when filling the battery. If the charging system is faulty, or the battery has been heated and boiled off too many times. Something should be repaired.

Answer 3

Because a battery is made up of lead plates and water, and water evaporates. They have sealed batteries, but in hot climates the water evaporates anyway, and sometimes they can explode if they get too hot. But don't worry, that seems to be very rare.

Answer 4

In the common lead acid batteries used in the automobiles, the charging cycle results in the formation of Pbo called as lead peroxide in the positive plate and pure lead in the negative plates.Chemical reaction during charging releases Hydrogen gas from the dilute(sp.gr=1.2) sulphuric acid electrolyte,depleting small H2o to result in increased acid gravity(up to 1.24) in charged cells. This loss of water and also water vapour in case of a rapid/excessive charging rate is made up by make up water by addition of distilled water only until the level covers the separators.Of course, the discharging cycle will result in formation of H2o to dilute the acid. The modern automatic voltage regulators(AVR) combined with the 3Ph alternator rectifier system monitors the charging rate(amps) sensing the battery voltage and keeping it in the range of 12 to 14.2 volts.The avoidance of excess charging which was common with the now obsolete electro-mechanical voltage-current regulators with DC generators has remarkably increased the battery life and as well avoided frequent topping of distilled water in lead acid batteries.

Answer 5

The chemical reactions in the batteryproduce
hydrogen sulphide gas in small quantities, the hydrogen comes from the water in the battery so a small amount is used up in an active battery. and the battery case is vented
so the gases go away.

Answer 6

Because a battery is made up of lead plates and water, and water evaporates. They have sealed batteries, but in hot climates the water evaporates anyway, and sometimes they can explode if they get too hot. But don't worry, that seems to be very rare.

Answer 7

Because a battery is made up of lead plates and water, and water evaporates. They have sealed batteries, but in hot climates the water evaporates anyway, and sometimes they can explode if they get too hot. But don't worry, that seems to be very rare...................VikramD

Answer 8

If your battery needs water often, odd are the battery is over charging. Check the voltage regulator for excessive charge voltage and if the cut off voltage is at the proper level.

Answer 9

Batteries in the vehicles are constanly charged. During charging Lead sulphate reacts with water to form lead, lead oxide, and sulphuric acid and all these generates electricity

Answer 10

To decrease the percentage of acid in the electrolite