How To Add Water To A Car Battery – Introduction And Symptoms

Modern dry batteries like gel don’t need refilling. However, older lead-acid car batteries require refilling from time to time. The water evaporates over time, making the battery less effective.

The best thing about these batteries is that you can restore some of the efficiency by refilling them. If you have such a battery, it helps to check its water level and top it up when you notice it getting lower.

Note that you cannot use just any water though. There is special distilled or ionized water designed specifically for such applications.

And today, we will be showing you how to refill the battery. You can easily do this at home without needing help from a mechanic.

How to Add Water to A Car Battery

Adding water to a wet car battery is quite simple. As stated above, it’s the water that gives your battery the energy to perform much faster. When you notice that your car is not starting well or that lights are much dimmer than normal, it could be time to get more water.

Follow these steps.

Step 1: Check the battery water level.

You should know that a low water level in a car battery is just as bad as over-filling. Therefore, it’s crucial first to check the level, making sure you don’t add water to a battery that is already full.

For this task, start by putting on protective eyewear and gloves. Personal protective equipment is crucial when working with batteries. You need something that covers your eyes completely, like goggles.

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Ensure the battery is designed for maintenance. Anything written “do not open” should not be opened. Also, ensure the car is turned on during the process.

Once that is confirmed, pry up the two cell port covers using a flat screwdriver. Start by sliding the edge of the screwdriver’s head from one side of the cover.

Each rectangular cover holds three cell ports. Check the water level on each of these ports.

If the cell port is round, twist off the covers, starting from one end of the row. The number of cell ports is the same both for rectangular caps and round caps.

Now wipe around the ports using a rag. A clean surface protects the battery from corrosion while keeping you safe too. Removing the cell port covers ensures you get rid of the dirt under the caps properly.

Check under each cap, ensuring each metal plate is fully submerged in the water. A close examination is crucial to revealing whether any plate is exposed.

The normal water level is about ? below the top of the cell. So, if you don’t see any exposed plates, your battery has enough water. Underperformance could be due to another reason.

Step 2: Add water.

Here are the steps to adding water to your car battery.

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Step 1: Fully charge the battery.

Run the engine first for about 30 minutes to charge the battery fully. Doing this ensures you don’t overfill the cells. Also, keeping a lead-acid battery charged is good for an extended lifespan.

Turn off the engine when you want to start adding the water. This is to ensure your personal safety as well as to keep the car free from possible corrosion.

Step 2: Get the right battery water.

Only distilled and deionized water is recommended for refilling car batteries. You can purchase this water from your local battery store.

The water does not contain any minerals, which makes it safe for batteries. Also, your battery only consumes water. Do not attempt adding in sulfuric acid or anything else that you think will help your battery.

Step 3: Add water to the battery.

Use a turkey baster or small funnel to draw water from the bottle to the battery. Use just enough water to cover the exposed plates.

Don’t overfill by covering the cells all the way to the rim. This could cause a leakage that will cause corrosion to your car parts. If you overfill accidentally, use the funnel to suck out the excess water.

Step 4: Replace the covers.

Once you have finished filling your battery with water, replace the covers correctly. Snap each rectangular cap in place and makes sure they are well tightened before starting your car.  

Note: do not start the car until all the caps are secured in place. Double-check each cap to ensure none is lost.

How Much Water Does a Car Battery Need?

As much as a car battery requires water, it does not mean you have to fill it to the brim. And that is why we have mentioned checking the water level in our guide above.

The electrolyte in a wet-cell battery should be 1/8 inch to 1/4 inch under the fill tubes extending from the opening of each battery. Remember only to use distilled water.

Why is it important to check the water level? Because there could be leakages that will lead to corrosion. During charging, the electrolyte solution increases in density. Overfilling will make cause the liquid to expand and overflow during this process, leading to possible damage.

Low Water in a Car Battery Symptoms

There are several symptoms of low car battery water. Generally, you will notice the reduced performance of the battery. This can be summarized using the following three indicators.

Low Battery Capacity

The optimal functioning of the battery is only possible at the normal range of the electrolyte. A new battery carries a concentration of about 38% sulfuric acid, which increase as the battery consumes water. Low battery water makes the process happen quicker, struggling to hold a charge for a long time.

Corrosion

Low battery water means exposed plates. When the plates meet oxygen in the atmosphere, corrosion happens. You will notice this issue inside the battery as it affects the negative electrode more.

Slow Cranking

The electrolyte needs sufficient high concentration to give your battery the boost it needs to start the car. Incorrect dilution leads to starting problems because the concentration is not enough. If you can catch the problem early enough, add water to your battery, and everything should be fine again.