A lawn mower with a dead battery is every homeowner’s summertime nightmare. You’re ready to tackle the overgrown grass, but the mower sputters and refuses to start. Instead of rushing out to buy a new battery, which can be costly, consider attempting to revive your existing one. With the right knowledge and a bit of effort, you might be able to save money and avoid unnecessary waste. This guide will walk you through various methods to bring your lawn mower battery back to life, from simple checks to more advanced techniques.
Understanding Lawn Mower Batteries and Why They Die
Lawn mower batteries are typically 12-volt lead-acid batteries, similar to those found in cars, but often smaller. They provide the initial power to start the engine. Over time, these batteries can lose their ability to hold a charge due to several factors.
Sulphation is a common culprit. This occurs when lead sulfate crystals accumulate on the battery plates, reducing the battery’s surface area and its ability to store and release energy. Deep discharges, where the battery is repeatedly drained completely, accelerate this process.
Another reason is sulfation, which is a chemical reaction that builds up lead sulfate crystals on the battery plates. This reduces the battery’s capacity to hold a charge.
Age is another significant factor. Like any battery, lawn mower batteries have a limited lifespan, typically ranging from three to five years. As they age, their internal components degrade, leading to reduced performance and eventual failure.
Extreme temperatures can also impact battery life. Hot weather can accelerate corrosion and water loss, while cold weather can reduce the battery’s ability to hold a charge.
Finally, infrequent use can contribute to battery problems. When a lawn mower sits idle for extended periods, the battery can slowly discharge, leading to sulfation and reduced performance. Proper storage and maintenance are crucial to prevent these issues.
Preliminary Checks Before You Start
Before diving into complex revival methods, perform a few simple checks to rule out other potential problems. This can save you time and effort if the issue isn’t the battery itself.
Start by inspecting the battery terminals. Look for corrosion, which appears as a white or greenish buildup. Disconnect the terminals and clean them thoroughly with a wire brush or a mixture of baking soda and water. Make sure the connections are tight and secure after reconnecting.
Check the battery’s physical condition. Look for cracks, bulges, or leaks. If you notice any of these issues, the battery may be damaged beyond repair and should be replaced.
Examine the battery cables for any signs of damage, such as cuts, frays, or corrosion. Replace any damaged cables to ensure a proper connection.
Verify the fuse or circuit breaker associated with the starting system. A blown fuse or tripped breaker can prevent the mower from starting, even with a healthy battery.
Finally, ensure the battery is properly seated and secured in its compartment. A loose battery can vibrate and cause intermittent connections, leading to starting problems.
Charging a Dead Lawn Mower Battery
The simplest method to revive a dead lawn mower battery is to recharge it using a battery charger. This is often sufficient for batteries that have simply lost their charge due to inactivity.
Use a trickle charger or a smart charger designed for lawn mower batteries. A trickle charger delivers a slow, steady charge over an extended period, which can help desulfate the battery plates. A smart charger automatically adjusts the charging rate based on the battery’s condition, preventing overcharging.
Before connecting the charger, disconnect the battery from the mower. This prevents any potential damage to the mower’s electrical system.
Connect the charger clips to the battery terminals, ensuring proper polarity (positive to positive, negative to negative). Follow the charger’s instructions for setting the voltage and charging rate.
Allow the battery to charge fully, which may take several hours or even overnight. Monitor the charging process to ensure the battery doesn’t overheat.
Once the battery is fully charged, disconnect the charger and reconnect the battery to the mower. Attempt to start the mower to see if the battery has been successfully revived.
If the battery charges fully but still fails to start the mower, there may be an underlying issue with the mower’s starting system or the battery may be damaged beyond repair.
Desulfating a Lawn Mower Battery
If simply charging the battery doesn’t work, sulfation may be the problem. Desulfation is the process of breaking down the lead sulfate crystals that have accumulated on the battery plates. Several methods can be used to desulfate a lawn mower battery.
One option is to use a desulfating charger, which is specifically designed to reverse the sulfation process. These chargers typically deliver a series of high-voltage pulses that break down the sulfate crystals.
Alternatively, you can attempt to desulfate the battery using a homemade solution. This method involves carefully adding Epsom salts (magnesium sulfate) to the battery’s electrolyte.
To do this, first, carefully remove the battery caps and check the electrolyte level in each cell. If the electrolyte level is low, add distilled water to bring it up to the proper level.
Next, prepare a solution of Epsom salts and distilled water. Mix approximately one ounce of Epsom salts per quart of distilled water, stirring until the salts are completely dissolved.
Carefully add the Epsom salts solution to each cell of the battery, filling them to the same level as before. Replace the battery caps and shake the battery gently to mix the solution.
Charge the battery using a low-amperage charger for several hours or overnight. Monitor the charging process and check the battery voltage periodically.
After charging, disconnect the charger and allow the battery to rest for several hours. Then, check the battery voltage again. If the voltage has increased significantly, the desulfation process may have been successful.
The Aspirin Trick: Fact or Fiction?
One popular, albeit controversial, method for reviving a dead battery involves using aspirin. The theory is that the acetylsalicylic acid in aspirin can react with the lead sulfate crystals on the battery plates, breaking them down and restoring the battery’s ability to hold a charge.
To try this method, crush several aspirin tablets into a fine powder. The exact number of tablets depends on the battery’s size, but a general guideline is to use about two tablets per cell.
Carefully remove the battery caps and drop the aspirin powder into each cell. Replace the battery caps and shake the battery gently to distribute the powder.
Charge the battery using a low-amperage charger for several hours or overnight. Monitor the charging process and check the battery voltage periodically.
While some people claim that this method is effective, others remain skeptical. There is limited scientific evidence to support the claim that aspirin can significantly improve battery performance.
It’s also important to note that adding foreign substances to a battery can potentially damage it. Use this method with caution and be aware of the risks involved.
Taking Precautions and Safety Measures
Working with batteries involves certain risks, so it’s essential to take precautions to protect yourself and prevent accidents.
Always wear safety glasses and gloves when handling batteries. Battery acid is corrosive and can cause serious burns.
Work in a well-ventilated area to avoid inhaling battery fumes, which can be harmful.
Avoid smoking or using open flames near batteries, as they can produce flammable hydrogen gas.
Disconnect the battery from the mower before performing any maintenance or repairs.
Never short-circuit a battery by connecting the positive and negative terminals directly. This can cause a fire or explosion.
Dispose of dead batteries properly. Many auto parts stores and recycling centers accept used batteries for recycling.
When to Say Goodbye: Knowing When to Replace Your Battery
While attempting to revive a dead lawn mower battery can be cost-effective, there comes a point when it’s simply not worth the effort. If your battery exhibits any of the following signs, it’s likely time for a replacement.
If the battery is cracked, bulging, or leaking, it’s damaged beyond repair and should be replaced immediately.
If the battery fails to hold a charge even after repeated charging attempts, it’s likely sulfated or has internal damage.
If the battery is more than five years old, its performance may be significantly degraded, and it may be more reliable to replace it.
If the battery frequently dies or struggles to start the mower, even after being fully charged, it’s a sign that it’s nearing the end of its lifespan.
Replacing a lawn mower battery is a relatively simple and inexpensive task. A new battery will provide reliable starting power and ensure that your mower is ready to tackle your lawn care needs.
Preventive Maintenance to Extend Battery Life
The best way to avoid the hassle of dealing with a dead lawn mower battery is to practice preventive maintenance. Proper care and storage can significantly extend the battery’s lifespan and prevent many common problems.
Keep the battery terminals clean and corrosion-free. Regularly clean the terminals with a wire brush or a mixture of baking soda and water.
Store the battery in a cool, dry place during the off-season. Extreme temperatures can damage the battery and reduce its lifespan.
Use a battery maintainer or trickle charger during periods of inactivity. This will keep the battery fully charged and prevent sulfation.
Avoid deep discharges. Try to avoid running the mower until the battery is completely dead.
Check the battery voltage periodically. A healthy battery should maintain a voltage of around 12.6 volts.
By following these preventive maintenance tips, you can keep your lawn mower battery in good condition and avoid the frustration of a dead battery when you need it most.
Choosing the Right Replacement Battery
If your battery is beyond repair, selecting the right replacement is crucial for optimal performance and longevity. Consider these factors when choosing a new lawn mower battery.
Ensure that the replacement battery has the same voltage and amperage rating as the original battery. This information is usually printed on the battery label.
Choose a battery that is specifically designed for lawn mowers. These batteries are typically more durable and resistant to vibration than automotive batteries.
Consider the battery’s cold cranking amps (CCA) rating. This indicates the battery’s ability to start the mower in cold weather. A higher CCA rating is generally better.
Opt for a reputable brand with a good warranty. This will provide peace of mind and protect you against defects.
Read online reviews to get feedback from other users about the battery’s performance and reliability.
By carefully considering these factors, you can choose a replacement battery that will provide reliable starting power for years to come.
Conclusion: Keeping Your Lawn Mower Running Smoothly
Reviving a dead lawn mower battery can be a rewarding and cost-effective way to extend its lifespan. By understanding the causes of battery failure, performing preliminary checks, and employing appropriate charging and desulfation techniques, you can often bring a battery back to life. However, it’s important to recognize when a battery is beyond repair and needs to be replaced. Regular maintenance and proper storage are crucial for preventing battery problems and ensuring that your lawn mower is always ready to tackle your lawn care needs. With a little knowledge and effort, you can keep your lawn mower running smoothly and avoid the frustration of a dead battery.
What are the most common reasons for a lawn mower battery to fail?
Lawn mower batteries commonly fail due to a few key reasons. One major factor is simply age; like any battery, lawn mower batteries have a limited lifespan and will eventually degrade with repeated charge and discharge cycles. Another common cause is improper storage, especially during the off-season. Leaving the battery in the mower throughout the winter, particularly in cold temperatures, can lead to sulfation, a process where lead sulfate crystals build up on the battery plates, reducing its ability to hold a charge.
Furthermore, infrequent use can contribute to battery failure. When a battery sits idle for extended periods, it can slowly discharge, leading to sulfation and a diminished capacity. Overcharging, either through a faulty charging system or leaving the battery on a charger for too long, can also damage the battery’s internal components, shortening its lifespan. These factors, often combined, contribute to the majority of lawn mower battery failures.
How can I test my lawn mower battery to see if it needs replacing or just recharging?
Testing your lawn mower battery is crucial to determine if it needs replacement or simply a recharge. The most reliable method involves using a multimeter, a tool that measures voltage, current, and resistance. First, ensure the battery is disconnected from the mower. Set the multimeter to read DC voltage and connect the red probe to the positive terminal and the black probe to the negative terminal.
A fully charged 12-volt lawn mower battery should read around 12.6 volts or higher. If the reading is significantly lower, such as below 12 volts, the battery likely needs recharging. However, if after a full recharge, the voltage drops quickly or the mower still struggles to start, the battery may be unable to hold a charge and needs replacement. Another method is to take the battery to an auto parts store; most offer free battery testing services using specialized equipment that provides a more comprehensive assessment of the battery’s health and capacity.
What is sulfation, and how can I prevent it from damaging my lawn mower battery?
Sulfation is a chemical process that occurs when a lead-acid battery, like the ones commonly used in lawn mowers, is left discharged for extended periods. During sulfation, lead sulfate crystals form on the battery’s lead plates. These crystals reduce the surface area available for electrochemical reactions, hindering the battery’s ability to accept and deliver a charge. Over time, sulfation can harden, becoming difficult or impossible to reverse, ultimately leading to battery failure.
Preventing sulfation is crucial for prolonging the life of your lawn mower battery. The most effective strategy is to keep the battery fully charged, especially during periods of inactivity, such as the winter months. Using a trickle charger or battery maintainer to provide a small, continuous charge can prevent the battery from discharging and sulfating. Also, avoid leaving the battery in a discharged state for any length of time; recharge it as soon as possible after use.
What are some safe practices to follow when charging a lawn mower battery?
Safety is paramount when charging a lawn mower battery. Always charge the battery in a well-ventilated area to prevent the buildup of potentially explosive hydrogen gas that can be released during the charging process. Wear safety glasses and gloves to protect your eyes and skin from battery acid, which is corrosive. Before connecting the charger, ensure the battery terminals and charger clips are clean and free of corrosion.
When connecting the charger, double-check the polarity. The positive (+) charger clip should be connected to the positive (+) battery terminal, and the negative (-) clip to the negative (-) terminal. Reversing the polarity can damage the battery and the charger. Use a charger specifically designed for lead-acid batteries and follow the manufacturer’s instructions for charging time and voltage. Avoid overcharging the battery, as this can lead to damage and a shorter lifespan. Once the battery is fully charged, disconnect the charger and store the battery in a cool, dry place.
Can I use a car battery charger to charge my lawn mower battery?
While it’s technically possible to use a car battery charger to charge a lawn mower battery, it’s generally not recommended without careful consideration. Car battery chargers are often designed to deliver a higher amperage than what’s optimal for a smaller lawn mower battery. Exposing a lawn mower battery to such a high current can lead to overcharging, overheating, and ultimately damage to the battery’s internal components.
If you must use a car battery charger, ensure it has a low amperage setting, ideally 2 amps or less, and closely monitor the charging process. It’s best to use a trickle charger or a battery maintainer specifically designed for lawn mower batteries, as these chargers deliver a lower, more controlled current, preventing overcharging and extending the battery’s lifespan. Using the appropriate charger ensures both safety and optimal battery performance.
How should I store my lawn mower battery during the off-season (winter)?
Proper storage of your lawn mower battery during the off-season is crucial for maintaining its health and longevity. The most important step is to fully charge the battery before storing it. A fully charged battery is less susceptible to sulfation, a major cause of battery failure. Clean the battery terminals to remove any dirt or corrosion, as this can lead to self-discharge.
Store the battery in a cool, dry place where temperatures are consistent and above freezing. Extreme temperatures can damage the battery. Ideally, store it in a garage or shed, but avoid leaving it on a concrete floor, as this can accelerate discharge. Periodically check the battery’s voltage throughout the winter, and if it drops below 12.4 volts, use a trickle charger or battery maintainer to bring it back to full charge. This will help prevent sulfation and ensure the battery is ready for use in the spring.
What are the signs that my lawn mower battery is beyond repair and needs to be replaced?
There are several telltale signs that indicate your lawn mower battery is beyond repair and requires replacement. One of the most obvious signs is the battery’s inability to hold a charge. If you fully charge the battery, but it quickly loses its charge or fails to start the mower after only a short period, it’s likely nearing the end of its lifespan. Visible damage, such as cracks, bulges, or leaks in the battery casing, also indicates that replacement is necessary.
Another sign is persistent starting problems. If the mower struggles to start, even with a fully charged battery, or if the engine turns over very slowly, the battery may not be providing sufficient power. Additionally, if a load test, performed with a multimeter or at an auto parts store, reveals that the battery’s voltage drops significantly under load, it’s a clear indication that the battery’s internal components have degraded and it needs to be replaced. Continually attempting to revive a severely damaged battery can be unsafe and may ultimately damage the lawn mower’s electrical system.