Can Lawn Mower Batteries Freeze?

As fall comes to a close and yard maintenance done, it is time to prepare your lawn mower for winter storage. If you own an electric lawn mower, you have to make sure the battery is stored properly so you don’t run into problems come next spring.

Lawn mower batteries will freeze in very cold temperature. Store it in a cool, dry place and make sure the battery is fully charged. You should also clean the battery terminals prior to storage to keep it in good condition.

A frozen battery is unusable and something you do not want to deal with. The good news is that it is fairly easy to winterize a lawn mower battery. In this post I will show it is done step by step.

How to Prevent Lawn Mower Batteries from Freezing

The following guidelines are for electric lawn mowers such as the Sun Joe AJ801E and others. If you own a gas lawn mower, batteries will not be a maintenance issue.

What You Need

• Rubber gloves
• Wire brush or Q tips
• Screwdriver
• Clean rag
• Anti-corrosion spray
• Trickle charger (optional)
• Battery container (optional)
• Safety glasses

Step 1

Put the safety glasses and gloves on. Anytime you are handling batteries and electrical equipment, you have to take precaution.

Turn off your lawn mower and clean it. With a gas model you usually empty the fuel tank. With an electric lawn mower, you remove the battery.

Battery removal varies per model, so follow the instructions in your owner’s manual. Get rid of the clippings, dust and dirt on the blade. Inspect the rest of the mower and clear all the dirt and debris.

Once you have cleaned the lawn mower, go to step 2 for the battery itself.

Step 2

Lawn mowers use different types of deep cycle batteries but prepping it for winter is the same process.

I want to point out that the battery location varies. With most riding mowers it is below the seat or the hood. With other models it might be somewhere else. Check your manual. If you own a push lawn mower, look for the terminals. That will tell you where the battery is.

Use a screwdriver to remove the terminal clamps. Remove the negative clamp and then the positive one. Place the screws in a safe location so you don’t lose them.

Get a clean piece of cloth and wipe the grease from the battery terminals. If there is corrosion, use NOCO E404 corrosion cleaner and a wire brush. Apply corrosion protection on the terminals after cleaning. Aside from a rag, you can use Q tips to clean the terminals. Be as thorough as possible.

Step 3

Now that the battery is thoroughly cleaned, you can store it for winter. Choose a cool, dry place where it is protected from the winter cold. You can use a battery container or just put it somewhere safe from cold.

I want to add one thing though: while our focus is to protect the battery from cold, you also have to keep it away from extreme heat, moisture, rain and any elements that might corrode it.

Step 4

After you find a location, give the battery a full charge. If the battery is lead acid, recharge it every 2-3 weeks. If it is lithium, check your owner\s manual. In general, you can charge lithium batteries every 8 weeks or whenever the capacity drops to 45%.

Tips for Storing Lawn Mower Batteries

Use a trickle charger. If you don’t want to recharge, get a trickle charger. Once you store the battery for winter, plug the charger in. When the capacity drops, the charger turns on and tops the battery.

There is no need to do maintenance because the trickle charger does it automatically. It also turns off once the battery is full, so no overcharging risk. And yes, this can go on for months on end.

My pick is the Battery Tender. If you don’t want to recharge in winter, then this is for you as it does the job well.

Always store batteries indoors. If you are going to remove the battery from your lawn mower, store it in a room or anywhere indoors cool and dry. This is not just for winter but the whole year.

Batteries lose charge when not used for a long time. Exposure to cold and heat speeds up power loss, so proper storage is key. This is why I recommend that you store the battery indoors and hook it up to a trickle charger.

Never leave the lawn mower on in storage. Leaving it on will damage the mower and the battery too. Make sure the engine and the ignition are both turned off. If the ignition is left on during winter storage, it will cause severe damage.

Why Lawn Mower Batteries Freeze

Batteries are filled with chemicals that allow it to conduct electricity. In extreme cold, these chemical liquids freeze.

Modern batteries have anti-freeze protection, but lack of use during winter storage makes the battery vulnerable. If the battery is not fully charged it becomes even more prone to the cold.

Once a battery is frozen it can no longer be used. I don’t recommend trying to fix it because it almost never works. You are better off just buying a new battery.

The terminals are crucial and must always be clean. Corrosion is more likely to build up if the terminals are dirty. Don’t wait for winter to clean them. Make it part of your lawn mower maintenance.

Frequently Asked Questions

Where is the best place to store lawn mower batteries in winter?

Somewhere cool and dry. You can put the batteries in a room, crawl space, closet etc. Basically anywhere that isn’t too cold and it won’t get wet. Do not put the battery near the kitchen sink because it could get wet.

Corrosion sets in moist and humid conditions. Keep the battery out of these places in your home. Along with very cold temperature, corrosion can cause irreparable damage.

Why do I need to charge the battery if I am not going use the lawn mower?

Charging lawn mower batteries before winter storage seems counter intuitive. After all you are not going to use it. Wouldn’t you save more battery power by not charging?

Charging batteries before storage is necessary for two reasons.

One, a battery loses power even when not in use. If you stored the battery with only 40% power left for winter, there might be nothing left in spring.

Second, recharging a 100% empty battery takes a long time. It can also cause long term damage. Lead acid batteries – the most commonly used in lawn mowers – should be recharged when capacity drops below 50%.

By fully charging the battery, there will be power left when you take the mower out in spring. You can even use a trickle charger to keep the battery 100% full at all times during storage.

How long can a lawn mower battery remain in storage unused?

An AGM battery is good for up to a year in storage, provided it is fully charged. A flooded lead acid battery needs to be recharged every few weeks or more often. With lithium batteries it varies.

If you do not plan on using the battery for months, give it a full charge and use a trickle charger. Or you can recharge the battery manually. If you do this, the battery should be fine come spring.

Can you revive a dead lawn mower battery?

Inspect the connections. Some might have come loose during storage and needs tightening up. The terminal connections might have gotten loose when you last used the lawn mower.

You should also check if the charger is working. Use another charger. If that works, it means the battery is fine and you had a defective charger. If you tried a new charger and the battery is still not working, it is dead and must be replaced.