The lead-acid battery is key to smooth vehicle performance, managing energy storage, and powering essential electrical systems.
But like any hardworking component, it requires regular TLC — including timely water refills to maintain the right battery water level. Ignoring this can lead to issues like flickering headlights or, worse, a car that refuses to start.
Sounds familiar?
Then, your battery may need a water top-up.
We’ll go over the tell-tale signs indicating your car needs a refill and walk you through the process of battery watering. We’ll also cover crucial watering guidelines to help you perform the refill safely.
Let’s begin!
This Article Contains:
- Why Does a Car Battery Need Water?
- 5 Urgent Signs Your Car Needs Battery Water
- How to Add Battery Water Step-By-Step
- What Type of Water Should You Use for Your Car Battery?
- 10 Vital Safety Measures to Follow During Battery Watering
- How Much Does It Cost to Add Battery Water to Your Vehicle?
- 4 FAQs about Battery Water
Why Does a Car Battery Need Water?
Lead-acid batteries require water to generate electricity. The battery creates electricity through a chemical reaction between the lead plates and the electrolyte solution. This solution consists of sulfuric acid and purified water.
Ample water is needed for the chemical reaction to be successful, especially when the battery is charging.
Why?
Every time the battery charges, the electrolyte solution inevitably heats up and experiences water loss due to evaporation. As this continues, the sulfuric acid concentration increases, resulting in sulfation and affecting battery life in the long run.
Routine refills help maintain an appropriate water-acid balance, prevent premature battery wear, and ensure consistent energy storage.
Now that you know why water is essential, let’s check whether you require a battery watering service or not.
5 Urgent Signs Your Car Needs Battery Water
When your vehicle is running out of water, you’ll notice:
- The car struggles to start
- Electrical accessories like headlights flicker and dim often
- The battery or check engine light turns on
- Battery struggles to hold charge
- Rust accumulates on the battery terminals
NOTE: When an AGM or lithium-ion battery malfunctions, you’ll notice similar symptoms. However, it doesn’t mean they need deionized water to resolve the problem. Instead, parts like the faulty alternator, internal cells, or battery charger may need attention.
If any of the above signs sound familiar, then your battery needs refilling. Keep scrolling to learn how.
How to Add Battery Water Step-By-Step
CAUTION: Battery water contains toxic acid, which can be dangerous if not handled carefully. So it’s best to let a professional perform this task.
Here’s how an automotive mechanic will water your battery:
- Wear the appropriate safety gear.
- Disconnect the battery. Then, remove the vent cap and clean the surface around the battery terminals with baking soda solution.
NOTE: Cleaning the terminals with baking soda will prevent contaminants from entering the battery.
- Twist the battery cap off each cell and use a damp cloth to wipe any grime accumulated around them.
- Observe the electrolyte solution and check if the battery water level is:
- 1/2 inch above the top of the lead plate or
- 1/8 inch below the filler tube bottom.
- Charge the battery using a charger before filling it with pure water.
- Use a funnel to carefully add distilled or deionized water to each cell. Pour only enough water to cover the lead plates (also known as positive and negative electrodes).
- Close the vent and battery caps, then seal them shut.
- Wipe any fluid that overflows.
- Reconnect the battery — positive terminal first, followed by the negative terminal.
NOTE: This procedure applies to lead-acid batteries only. You can’t add water to an AGM battery since it’s usually maintenance-free. Similarly, an electric vehicle with a lithium-ion battery doesn’t require a water refill, as it’s a sealed unit.
But before you opt for the service, you must choose the right fluid and water source for refilling.
What Type of Water Should You Use for Your Car Battery?
Always use deionized or distilled water for your flooded battery, and never tap water.
Tap water often contains small amounts of minerals, chlorides, and other impurities that can react with sulfuric acid and harm your lead-acid battery. These impurities may also react with the lead plates, causing permanent damage.
Car owners must be vigilant and only use pure water from undamaged containers during routine maintenance.
Besides the fluid type, there are other watering guidelines that you should consider while refilling.
10 Vital Safety Measures to Follow During Battery Watering
Refer to these vital tips to prevent mishaps during water refill:
- Park your vehicle in a well-ventilated and flat area.
- Always wear proper eye protection goggles and gloves.
- Wear personal protective equipment (PPE) for protection against accidental battery acid spillage.
- Refill the battery only after it has completely cooled down after charging.
- Don’t touch the electrolyte solution with bare hands.
- Rinse your face and hands with water and soap thoroughly if they come in contact with the acid.
- Keep metal objects and flames away from the battery.
- Don’t overwater the battery, which may dilute the electrolyte solution, impacting battery performance. Be especially careful with older batteries, as they are quick to overflow, causing further damage and corrosion.
- Avoid underwatering to prevent sulfation.
- Clean or dispose of any used safety gear to prevent spilled battery acid from coming in contact with other objects.
Considering these risks and restrictions, it’s best to schedule a professional watering service to avoid the hassle.
Let’s check out how much it’ll cost you.
How Much Does It Cost to Add Battery Water to Your Vehicle?
A repair shop may charge roughly $85 to $200 to add new battery water. This estimate includes:
- Battery water cost: $10 to $30
- Labor costs: $75 to $170
Want to know more about battery water?
Keep reading to go over some queries related to it.
4 FAQs about Battery Water
Below are the answers to some commonly asked questions about battery water:
1. What Is Sulfation?
Sulfation is the excess buildup of lead sulfate on battery plates (positive and negative electrodes). It’s one of the most common problems you can face with a lead battery. Various factors, including a low electrolyte level, overcharging, and undercharging, can cause it.
Remember, lead sulfate can cause irreversible damage to the plates and shorten battery life.
2. How Do You Check Your Car Battery’s Electrolyte Level?
After removing the vent and battery caps, you can visually inspect the electrolyte levels by observing the lead plates in each battery cell.
Here’s how to identify the level of your battery’s electrolyte solution:
- Low: If the battery plates are entirely exposed, the electrolyte solution level is very low and needs to be refilled.
- Standard: This is when the electrolyte is about 1/2 inch above the lead plates or 1/8 inch below the filler tube bottom. Don’t add water beyond this point.
- Maximum: If the battery’s fluid level touches the bottom of the filler tubes, it’s best to stop refilling.
3. How Often Should You Water Your Vehicle Battery?
Typically, you should add battery water every 5 to 10 charging cycles. You can also ask an automotive mechanic to check the water level every three to six months to ensure the battery isn’t low on purified water.
However, the frequency of refills will also depend on:
- Your battery’s age
- How often you charge the lead battery
- How long the battery can hold charge
- Your car usage
- The local weather – extreme heat can lead to excess water loss.
4. What Happens If Flooded Lead-Acid Batteries Run Out of Water?
If the distilled water runs out, the concentration of sulfuric acid will increase, resulting in poor battery performance and reduced lifespan.
Eventually, the battery will overwork to compensate for less water, generating excess heat. This heat can release sulfuric vapors that will corrode components like lead plates and terminals.
In the worst case, the heat can permanently damage the battery, requiring a complete replacement.
So, it’s best to refill the battery routinely to avoid unnecessary problems.
Battery Maintenance Made Easy with AutoNation Mobile Service
Battery problems caused by low electrolyte levels are easy to prevent. Regular refilling and maintenance will keep your battery’s health in check, helping you avoid costly replacements.
However, if you’re unfamiliar with battery maintenance and find it overwhelming, call professionals from AutoNation Mobile Service for assistance. Our technicians can help car battery owners with water refills and other repair services.
We also offer upfront pricing and simple online bookings to make the repair convenient and easy.
Contact us, and our experts will be at your driveway in no time.