How To Store A Lawn Mower Battery For Winter Properly

Can you store a lawn mower battery for winter? Yes, you absolutely can and should store your lawn mower battery properly for winter to ensure its longevity and prevent damage. Storing it correctly is a key part of lawn mower maintenance that significantly extends its battery life.

As the leaves turn golden and the air grows crisp, it’s time to think about putting your trusty lawn mower away for the winter. But before you cover it up and forget about it until spring, there’s one crucial component that needs special attention: the battery. Improper storage can lead to a dead battery by the time the snow melts, leaving you with an unexpected expense and a delayed start to mowing season. This guide will walk you through everything you need to know about winter storage for your lawn mower battery, ensuring it’s ready to go when the grass starts growing again.

Why Proper Battery Storage Matters

A lawn mower battery, whether it’s a traditional lead-acid battery or a more modern type, is susceptible to damage from extreme temperatures and self-discharge during periods of inactivity. Cold weather can significantly slow down the chemical reactions within the battery, but it can also cause irreversible damage if the battery is discharged. If a lead-acid battery is left in a discharged state in freezing temperatures, the electrolyte can freeze and expand, cracking the battery case.

Self-discharge is a natural process where a battery gradually loses its charge over time. If a battery is left uncharged for too long, its voltage can drop too low. This deep discharge can permanently harm the battery, especially lead-acid battery types, making it difficult or impossible to recharge.

Preparing Your Lawn Mower Battery for Storage

Before you even think about where to place the battery for winter storage, some essential preparation steps are necessary. These steps ensure the battery is in the best possible condition before entering its dormant phase.

Cleaning the Battery

Start by thoroughly cleaning the battery. Remove any dirt, debris, or corrosion from the terminals and casing. Use a wire brush and a solution of baking soda and water to clean the terminals. This helps ensure good electrical contact when you reconnect the battery in the spring. Make sure to wear gloves and eye protection during this process.

Checking Fluid Levels (If Applicable)

Some older or specific types of lawn mower batteries are not sealed and have removable caps to check the electrolyte level. If your battery has these, check the fluid level. If it’s low, top it off with distilled water only. Never use tap water, as minerals can interfere with the battery’s performance. Be careful not to overfill.

Inspecting for Damage

Examine the battery casing for any cracks, leaks, or signs of swelling. If you find any damage, the battery may need to be replaced. Attempting to store or charge a damaged battery can be dangerous.

Charging the Battery Before Storage

This is a critical step in battery care. You should always charge the battery fully before storing it for winter. A fully charged battery is less prone to sulfation (the formation of lead sulfate crystals on the plates, which reduces capacity) and is better equipped to handle the effects of self-discharge.

Use the Correct Charger: Always use a charger designed for your specific battery type (e.g., a 12V charger for a 12V battery).
Follow Manufacturer Instructions: Consult your lawn mower’s owner’s manual or the battery manufacturer’s guidelines for specific charging instructions.
Avoid Overcharging: While modern chargers often have automatic shut-off features, it’s still best practice to monitor the charging process.

Using a Battery Tender

For optimal battery care and to maintain a full charge throughout the winter, using a battery tender (also known as a trickle charger or smart charger) is highly recommended. A battery tender is designed to keep a battery fully charged without overcharging it. It monitors the battery’s voltage and provides a small amount of current only when needed. This is especially beneficial for deep cycle battery types often found in riding mowers.

How a Battery Tender Works: A battery tender uses a multi-stage charging process. It first charges the battery to full capacity, then switches to a “float” or “maintenance” mode, delivering just enough power to counteract self-discharge.
Benefits of a Battery Tender:
- Prevents overcharging and damage.
- Maintains optimal voltage levels.
- Minimizes sulfation.
- Ensures the battery is ready to use in the spring.
- Extends overall battery life.

Disconnecting the Battery from the Mower

For safety and to prevent any accidental engagement of the mower’s electrical system, it’s essential to disconnect the battery from the lawn mower itself before storage.

Identify Terminals: Locate the positive (+) and negative (-) terminals on the battery.
Disconnect Negative First: Always disconnect the negative (-) terminal first. This prevents accidental short circuits if your wrench touches the mower’s metal frame while disconnecting the positive terminal.
Disconnect Positive: Next, disconnect the positive (+) terminal.
Secure Cables: Ensure the battery cables are not touching any metal parts of the mower. You can secure them with zip ties or electrical tape.

Optimal Storage Locations and Conditions

The environment where you store your lawn mower battery plays a significant role in its survival and performance during the off-season. Cold weather storage requires careful consideration of temperature and other factors.

Temperature Considerations

Ideal Temperature Range: The ideal storage temperature for most lead-acid battery types is between 32°F (0°C) and 68°F (20°C).
Avoid Extreme Cold: While a fully charged battery can withstand freezing temperatures better than a discharged one, prolonged exposure to temperatures well below freezing is still not ideal. If stored in an unheated garage or shed, a discharged battery is at risk of freezing and cracking.
Avoid Extreme Heat: High temperatures accelerate self-discharge and can degrade the battery’s internal components. Never store a battery in direct sunlight or near heat sources.

Suitable Storage Locations

Basements or Crawl Spaces: These areas often maintain a more stable, moderate temperature throughout the winter and are generally dry.
Heated Garages or Sheds: If you have a heated space, this would be the most ideal location, providing protection from extreme cold and fluctuations.
Unheated Garages/Sheds (with precautions): If your only option is an unheated space, ensure the battery is fully charged and preferably connected to a battery tender. Elevating the battery slightly off the concrete floor can also be beneficial, as concrete can absorb moisture and conduct cold.

What to Avoid

Direct Contact with Concrete: Storing batteries directly on concrete floors in unheated spaces can be problematic due to moisture absorption and cold conductivity.
Humid Environments: High humidity can lead to corrosion of terminals and electrical connections.
Areas with Sparks or Flames: Batteries, especially when charging, can produce flammable hydrogen gas. Keep them away from anything that could ignite this gas.

Storing the Battery Separately

It’s generally best practice to remove the battery from the lawn mower and store it separately. This protects both the battery and the mower. The mower might be subject to temperature swings or minor electrical draws that can slowly drain the battery. Storing it separately also makes it easier to check on and maintain with a battery tender.

Maintenance During Winter Storage

Even with proper preparation, it’s a good idea to perform occasional checks on your stored battery, especially if you’re not using a battery tender.

Checking Voltage

If you are not using a battery tender, you should check the battery’s voltage periodically, perhaps once a month. Use a voltmeter to measure the voltage across the terminals.

Ideal Voltage: For a 12V lead-acid battery, a fully charged state is typically around 12.6 to 12.8 volts. If the voltage drops below 12.4 volts, it’s a good indicator that the battery needs to be recharged.
Recharging: If the voltage is low, recharge the battery fully.

Recharging Schedule (Without a Tender)

If you don’t have a battery tender, you’ll need to manually recharge the battery at regular intervals.

Frequency: Aim to recharge every 30-60 days, depending on the battery’s capacity and the storage temperature. Colder temperatures slow self-discharge, but a discharged battery is still at risk.
Charger Use: Use your standard battery charger for these recharges. Again, ensure you follow the charging instructions and avoid overcharging.

Different Battery Types and Storage

While the general principles of winter storage apply to most lawn mower batteries, there can be slight variations depending on the battery type.

Lead-Acid Batteries (Flooded, AGM, Gel)

Flooded Lead-Acid: These are the most common type. They require the most attention to fluid levels and are most susceptible to freezing when discharged. Regular charging and a battery tender are crucial.
AGM (Absorbent Glass Mat) Batteries: These are sealed and maintenance-free. They are more vibration-resistant and can handle deeper discharges than flooded batteries. However, they still benefit greatly from a battery tender for winter storage to prevent sulfation and maintain optimal voltage.
Gel Batteries: Similar to AGM, gel batteries are also sealed and maintenance-free. They are generally more sensitive to overcharging than AGM batteries, so using a charger specifically designed for gel batteries or a smart battery tender is essential.

Lithium-Ion Batteries

As lithium-ion batteries become more common in smaller electric mowers, their winter storage needs differ.

Charge Level: Lithium-ion batteries generally prefer to be stored at a partial charge (around 50-70%) rather than fully charged or fully discharged. Check the manufacturer’s recommendations.
Temperature: While they are more tolerant of cold than lead-acid batteries, extreme cold can still affect their performance and lifespan. Storage in a moderate temperature range is still best.
No Battery Tender Needed (Usually): Most lithium-ion batteries have built-in Battery Management Systems (BMS) that prevent overcharging and deep discharge. They typically don’t require a constant battery tender like lead-acid batteries. However, it’s still wise to check the charge level every few months.

Storing the Lawn Mower Itself

While this guide focuses on the battery, remember that proper lawn mower maintenance extends to the entire machine.

Clean Thoroughly: Remove all grass clippings and debris.
Fuel System: For gas mowers, either drain the fuel tank or add a fuel stabilizer and run the engine for a few minutes to ensure the stabilized fuel circulates through the carburetor.
Oil Change: Consider changing the oil before storage.
Lubrication: Lubricate moving parts.
Storage Location: Store the mower in a dry, protected area.

Table: Winter Battery Storage Checklist

Step	Action	Notes
Preparation	Clean battery terminals and casing.	Use baking soda solution and wire brush. Wear gloves and eye protection.
	Check fluid levels (if applicable).	Top off with distilled water only.
	Inspect for damage (cracks, leaks).	Replace if damaged.
Charging	Fully charge the battery.	Use the correct charger for your battery type.
	Connect a battery tender for continuous maintenance.	Ideal for maintaining charge and preventing sulfation.
Disconnection	Disconnect the battery from the mower.	Disconnect negative terminal first, then positive.
Storage Environment	Choose a cool, dry location.	Ideal: 32-68°F (0-20°C). Avoid direct sunlight and extreme heat or cold.
	Store away from concrete if possible.	Elevate off the floor if in an unheated garage/shed.
Monitoring (No Tender)	Check voltage monthly.	Recharge if voltage drops significantly (e.g., below 12.4V for 12V lead-acid).
	Recharge manually every 30-60 days.	Avoid overcharging.
Spring Readiness	Reconnect battery to mower (positive first, then negative).	Ensure terminals are clean and connections are secure.
	Check mower fluid levels and perform any necessary pre-season maintenance.	Consult your owner’s manual.

Frequently Asked Questions (FAQ)

Q: Do I need to disconnect the battery before storing my lawn mower for winter?
A: Yes, it is highly recommended to disconnect the battery from the lawn mower for proper winter storage. This prevents any accidental draining and ensures the battery is stored optimally.
Q: Can I leave the battery connected to the mower if I use a battery tender?
A: While some battery tender systems are designed to connect directly to the mower’s battery terminals without removal, it’s still a good practice to disconnect the battery. This is for added safety and to isolate the battery from the mower’s electrical system, which could potentially have a small parasitic drain. Always follow the battery tender manufacturer’s specific instructions.
Q: What happens if I don’t store my lawn mower battery properly?
A: Improper storage can lead to several issues: the battery may lose its charge and become difficult or impossible to recharge (deep discharge), the electrolyte can freeze and damage the battery case in freezing temperatures, and sulfation can occur, reducing the battery’s capacity and lifespan.
Q: How long can a lawn mower battery last if stored properly?
A: With proper winter storage and regular maintenance (especially with a battery tender), a lawn mower battery can last for several years, typically 3-5 years for standard lead-acid battery types, and potentially longer for higher-quality batteries or lithium-ion types. Good battery care is key to maximizing battery life.
Q: Is it better to store the battery indoors or in the garage?
A: Storing the battery indoors in a climate-controlled environment (like a basement) is generally better than an unheated garage, as it provides more stable temperatures. However, if an indoor location is not feasible, an unheated garage or shed can work if the battery is fully charged and ideally connected to a battery tender, and if the temperature doesn’t drop excessively low for prolonged periods.
Q: Do I need a special charger for AGM or Gel batteries?
A: While a universal smart charger or battery tender can often work, it’s best to use a charger specifically designed for your battery type (AGM, Gel, or Lithium-ion). These chargers have specific voltage and current profiles to prevent damage. Consult your battery manufacturer’s recommendations.

By following these detailed steps, you can ensure your lawn mower battery survives the winter in peak condition, ready to power up your mower for the start of the next mowing season. Proper lawn mower maintenance that includes diligent battery care will save you money and frustration in the long run, extending your battery’s battery life and keeping your lawn looking its best.