Several factors can make a battery lose water. A battery is made up of an electrolyte and this electrolyte comprises sulfuric acid and water which are mixed in the right ratios.
For batteries to provide electrical power, there are chemical reactions that have to take place and it is the plates, electrodes, and the electrolyte that participate in the reactions.
For the chemical reactions to take place accordingly there is a need for a good environment where the ions can freely move and also a medium that gives the other ions needed for a complete reaction.
When charging goes on in a battery, there is an electric current which is induced in the battery. This makes water break down into its components which are hydrogen gas and oxygen gas. This process is called electrolysis. Some percentage of the gases will escape which causes the loss of water while a good percentage will recombine back into water.
Water forms a major component of the battery and as we shall discuss below, we will find out that if a battery loses water it can cause permanent damage to the battery. When the battery gets damaged it becomes costly to have it replaced.
Importance of Water in the Battery.
For chemical reactions to take place, water has to be present to provide the right environment.
Water is used to dilute the concentration of sulfuric acid which forms part of the electrolyte. Sulfuric acid is highly corrosive when in its concentrated form and can even corrode the battery electrodes eventually damaging the battery.
To prevent overheating of the battery, there is a need for cooling and water acts as a coolant in the battery. As the battery charges and discharges there are chemical reactions that take place and heat is produced in the process. Water transports this heat and has it dissipated to the environment resulting in the colling of the battery.
Water also provides ions which are needed for a complete chemical reaction to occur. For the ions to move freely, a conducive environment is a requirement and water helps in providing this environment.
Mixing of Water With Acid in the Electrolyte
As we have mentioned earlier, the battery electrolyte comprises of water and the acid. These two are mixed in the required ratios. The mixing however depends on the type of the battery and what the battery is used for. Generally, the concentration levels are known to be 65% water and 35% sulfuric acid in terms of volume.
The concentration ratios need to be right so that the chemical reactions take place optimally When the acid concentration is too high, the electrodes can get corroded, and again when the concentration is too low it means the sulfur ions will be few and the chemical reactions will be interfered with
To ascertain the concentration levels of the acid in the electrolyte, a specific gravity test can be done. What specific gravity does is it measures the density ratio of sulfuric acid to that of the water mixing it. The ideal specific gravity is given in a range in which it presents the required environment for the battery.
In cases where the specific gravity of the electrolyte falls below a specified level, it implies that the sulfuric acid in the electrolyte is less than water. This can be corrected by adding more concentrated sulfuric acid.
The reverse is true in the sense that when the specific gravity goes above the recommended range then it implies that there is less water than the acid in the mixture. In this case, it will be corrected by adding more distilled water.
Keep in mind that it is water that is added to acid and not acid added to water.
Can Battery Be Topped Up With Tap Water?
The answer to this is a NO. Tap water has other minerals in it which can react with sulfuric acid which forms part of the electrolyte. When the reaction occurs, sulfur products will be formed and they can hinder the chemical reactions from taking place as they should.
This will therefore mean that the battery will lose its capacity.
You should only add distilled water to the battery. Distilled water is also known as di-ionized water and it does not have any dissolved mineral compound. It is exclusively made of hydrogen and oxygen molecules. When you have the required equipment, you can make distilled water at home.
When is Water Added to The Battery?
If you are an individual who is keen on battery routine maintenance, then you will be able to note when the electrolyte water falls below the recommended level.
In most cases, the batteries have a transparent casing and one can see through the electrolyte level. Again, in most batteries, these electrolyte levels are marked indicating both the minimum and maximum levels. When you notice that the electrolyte level has fallen below the minimum mark, it is recommended to top up using distilled water.
In a case where the casing of the battery is not transparent and you cannot tell the level of the electrolyte, you can check the water levels in the cell. The plates of the battery should always be covered with the electrolyte. If you notice the plates are exposed it means the electrolyte levels are low and it is time to top up with distilled water.
How Much Water Should I Add to The Battery?
This is determined by the size of the battery and the extent to which the electrolyte level has dropped.
As we have mentioned above, in cases where the battery casing is transparent and you can see the electrolyte levels, you need to add distilled water up to the maximum level marked.
When dealing with a battery with no transparent casing, you need to add water up to the level where the electrolyte level rises to 75% full. Be keen not to fill the battery because that will lead to spillages.
As charging takes place, we had said earlier that the electric current induced into the water makes the water break into oxygen and hydrogen gas a process referred to as electrolysis. As this process takes place, bubbling is seen as if it’s boiling. In a case where you overfill the battery it will boil over and what happens next will be the acid spilling over.
Effects of Complete Battery Water Loss
Several things are bound to happen in this case. The water can be lost completely as a result of spillage, evaporation, or leakage. Below are some of the possible outcomes.
No Chemical Reaction Takes Place
For chemical reactions to take place in the battery the electrolyte which is made up of acid and water has to be there. The environment also has to be conducive for the reactions to take place optimally.
When the battery is charging the electrical energy is converted into chemical energy for storage while as the battery discharges the chemical energy is converted into electrical energy.
These reactions will not take place if the environment is not right and, in a case, where the battery has no electrolyte, it is as good as having a dead battery.
Corrosion of The Battery
In a case where water is lost, it means the concentration of the electrolyte will increase. Don’t forget that we had said the electrolyte is made up of 65% water and 35% sulfuric acid.
Acid is very corrosive and when the concentration goes beyond the required, it can lead to corrosion of the battery plates. When the plates are corroded it means the capacity of the battery to store charge will reduce and hence a damaged battery.
Overheating During Charging
We had mentioned earlier that water acts as the medium to transport heat and dissipate it to the environment during charging. When we lose water, it means we lose the heat transportation medium and therefore the battery will heat up.
When the heating continues and it reaches a level that the battery can no longer tolerate, thermal runaway will kick in and the battery can explode.
Oxidation of The Negative Electrode
The battery is made up of negative and positive electrodes. The positive electrode is made up of lead oxide and is hence a bit stable. The negative terminal, however, is made of lead alone. Lead is very unstable and spongy.
If the electrolyte is lost, the negative terminal which is made of lead alone will react with oxygen which is readily available in the air, and lead oxide will be formed.
Lead oxide is less reactive to the chemical combination that is needed to discharge and have the battery charged. What this results in, is an incapacitated battery.
Can Boiled Water Be Added to The Battery?
Boiling water does not make it appropriate to be added to the battery. The process of boiling only kills germs but does not remove the water minerals.
The answer to this question is therefore a NO.
Can Battery Lose Water Due to Overcharging?
Yes, Overcharging the battery increases the electrolysis process which means the process of water loss is speeded up. Besides the water loss, overcharging the battery is very dangerous because it can get to a point where the battery melts and gets permanently damaged.
Final Thoughts
Water is a very important component of the battery environment. For you to ensure you have the right water levels, make it a routine to do maintenance checks so that you have the right concentrations at all times.
When the ideal environment deviates, it means the environment for the chemical reactions has been altered and the battery capacity will be affected.