Symptoms of low water in a car battery: How to identify and resolve

By Arif

Automotive Battery

Car batteries are prone to discharging and getting faulty due to overcharging and many other technical reasons. One of the reasons many motorists may not be aware is low water levels. How to tell if your car battery is low on water? What are the symptoms of low water in a car battery?

If you are looking to find the answers to the above questions then this is the post to read. We will also cover the causes, preventions, and methods to fulfill the shortcomings of water levels in a car battery.

So, keep reading!

Symptoms of low water in a car battery

Symptoms of low water in a car battery include starting problems due to engine cranking, warning signs on the car dashboard, and battery losing charge repeatedly in quick time.

Extremely hot weather is another reason that evaporates the liquid of a car battery making it lose water.

Corrosion on the plates/terminals is a common cause of battery problems and can contribute to the symptoms of low water levels.

The corrosion aspect is often attributed to the lack of maintenance. So, if you are one of those lazy drivers who hardly bother about their vehicles then be ready to notice water abnormalities in the battery structure.

It is important to understand the technical aspects of the above symptoms that will help you take precautionary steps proactively and avoid major damage to the battery and overall vehicle.

But before diving into the symptoms it is important to understand the role of water components in an automotive battery.

‘Water’ in a car battery

The liquid component which is often mistaken with water is actually sulfuric acid. Yes, there is some water added to the acid chemical for the purpose of balancing the concentration liquid. With time and usage, this water starts reducing which is a normal process.

Generally, the water gets utilized as a part of the chemical reaction of the sulfuric acid electrolyte process within the batteries. As a result of this utilization, the water evaporates through battery vents in the form of hydrogen and oxygen gases.

To counter low water levels periodic inspection and maintenance are enough. However, there are some external sources that add to the woes of reducing water levels in a car battery.

If you begin to notice any of the following symptoms it is a potential indication of low water levels in your vehicle battery.

High temperatures

In extremely hot temperatures, the evaporating process of liquid happens much faster compared to normal circumstances.

Related Read: What makes car batteries explode

When the water starts declining it restricts the lead plates to perform the electrolyte process. This is essential for a car battery to function properly.

Water getting diminished means sulfuric acid getting more concentrated oxidizing the lead plates resulting in mal-functionality.

It is important to monitor the temperature levels while using your vehicle. If it’s getting too hot, ensure to check the water levels in your car battery regularly.

If the shortage is below the recommended levels fulfill the gap with distilled water for better performance, and smooth running of your vehicle.

Not able to hold a charge for too long

If you find that the car battery is losing its charge constantly it could be because of low water levels.

Car Battery having low charge

Again, when the water level reduces too low the sulfuric acid gets highly concentrated and disturbs the electrolyte process. This can result in the battery losing charge quickly.

The battery will not be able to hold the charge for too long on recharging until some effort is made to fulfill the water levels.

Battery corrosion

The corrosion aspect comes into the picture when the lead plates are unveiled to the outer environment. This is a result of water going below the recommended levels that exposes the lead plates.

Owing to this exposure there is a buildup of corrosion around the plates and battery terminals which makes it harder for the battery to continue the electrical flow.

If you find corrosion forming around battery terminals the first step you must take is to check the water capacity and bring it back to the recommended levels.

Starting problems

A weak battery has many impacts on the performance of a car and when there is slowness in starting the engine it could be another sign of a low water level.

A vehicle battery works on a chemical reaction to generate electricity that powers the engine and other electrical components. Lack of water limits the powering capacity of an engine that just produces a cranking/clicking noise instead of starting.

Warning battery signs

Signs of battery warnings on your car dashboard will get very common due to malfunctioning batteries.

Low battery sign on car dashboard

It is important to pay serious attention to the warning signs and oblige by inspecting the condition of the battery. If you find any of the above symptoms it is time to juice up the battery with the correct water levels.

Based on these symptoms you can take the necessary steps to energize your car battery including adding water. However, it is also imperative to know the causes behind a car battery losing water.

Causes of low water in a car battery

Overcharging – When the battery is overcharged courtesy of human error or by the alternator the excessive charge impacts the mixture of sulfuric acid and water.

As a result of overcharging, the electrolyte mixture begins to heat up and evaporate. This evaporation decreases the water level in the battery leaving it with less liquid to conduct electricity.

Lack of maintenance – Due to lack of maintenance, a car battery is vulnerable to internal leakages and damage.

Failure to inspect the condition of the battery in a timely manner attracts corrosion and rusting on its terminals.

Both scenarios are instrumental in reducing the water levels causing a battery to perform badly.

Temperatures – Exposure to very high temperatures limits the capacity of a car battery to hold its water level.

With constant heating, the water evaporates through battery vents leaving the sulfuric acid concentrate unbalanced. 

It is therefore crucial to inspect the water levels of a car battery as part of self-maintenance, monitor the charging process, and protect your vehicle by parking it under the shade or in a garage in hot weather.

How to add water to a car battery?

Once you have identified low water levels in a car battery here are the basic steps to follow for adding the water:

Adding water to a car battery
  • Move the car to the side of the road and turn off the engine
  • Let the car cool down for some time which will also result in cooling of the battery
  • Open the hood and locate the battery. Use the vehicle manual if you can’t find the battery or are not able to identify the battery structure.
  • Check the battery condition from the outside. If you find dust, and dirt take a cloth and clean it to avoid getting them mixed with the battery content.
  • Next, start removing the cell caps which are normally located on the top of the battery. Use a flathead screwdriver to unscrew the caps.
  • Check the water level in each cell. If you find the water level is below the top of the plates inside any of the cells, add distilled water until the water level reaches the max line or appropriate levels.
  • To find the max line it is again recommended to check your vehicle’s manual. If there is no max line identification fill the water till the bottom levels of battery vents that are visible in every cell.
  • Once you have filled all the cells with water replace the cell caps securely.
  • Lastly, clean any spills or residue around the battery with a cloth.

Note: All the above steps are irrelevant if your vehicle is equipped with maintenance-free or gel-sealed batteries. Such types of batteries do not have removable caps so you cannot perform the action of adding water.

As a precautionary step, if you are not familiarized with the process of adding water to a car battery it is better to take help from an automotive technician/mechanic to do the job.

Can I use a bottle or tap water to refill a car battery?

Bottle or tap water is mixed with contaminants that do not get well with the diluted sulfuric acid. It is recommended to use pure distilled water which is specifically designed to use on car batteries.

What happens if you overfill the car battery with water accidentally?

Overfilling a car battery with water can cause the electrolyte solution to overflow meaning spilling outside the battery case. This can damage the battery and its components when it is used to run the vehicle.

A small amount of overfilling may not impact much. The balancing act of water will take place after 2-3 instances of recharging.

It is there important and recommended to follow the maximum level signs for filling the water in a car battery. If you are not sure about doing it yourself then take your vehicle to the nearest garage.

How often should you check the water levels of a car battery?

Checking water levels every 6 months is a good practice to keep the battery in good shape and perform appropriately provided the vehicle is well-maintained periodically.

However, increased vigilance is required in hot weather conditions. A monthly inspection is more beneficial to counter the impacts of heat that diminish water quickly.

Final thoughts

Automotive batteries are prone to losing water with time and usage. The frequency of losing water increases due to various external factors such as weather, lack of maintenance, and improper usage of a vehicle.

Slow starting of the engine/cranking noise, dimmed lights, and inability to hold a charge are some of the common symptoms of a battery with a low water level.

It is important to identify these symptoms and initiate the process of refilling a car battery with distilled water as soon as possible.

More importantly, learn to counter the impact of low water in a car battery by acting proactively on the causes that lead to the reduced water situation.

Always keep your car well-maintained which will automatically cover the inspection and service of the battery in the appropriate manner.

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I am the founder of TheCarPlus. As a passionate car owner and enthusiast, I offer practical solutions and insights from my own personal experiences combined with extensive online research.

The purpose of creating this website is to empower fellow car owners and motorcyclists like 'YOU' with knowledge and practical solutions to enhance your vehicle's performance and aesthetics.

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