As winter approaches and your lawn mower goes into hibernation, it’s important to think beyond simply stowing the machine in the shed.
One of the most important aspects of winterizing modern lawn mowers is making sure that the battery is stored properly.
Cold weather for a prolonged period of time can be especially harsh on lawn mower batteries, causing issues like chemical degradation and power drain.
This can lead to premature wear, reduced capacity, or even complete battery failure by the time spring rolls around.
The Importance of Proper Battery Storage
Winter can affect all sorts of power tool batteries. Extended periods of low temperatures can slow down chemical reactions inside the batteries which reduces their charge capacity.
"It’s best to remove all batteries from your equipment and place them in a ventilated, climate-controlled area that remains dry and between 50°F-80°F all year round," explained Eric Halfman, Go-To-Market Manager, John Deere as he highlighted the brand's newest battery-powered tool, the Z370RS Electric ZTrak™ Mower. "We recommend choosing a location that is fully dry and protected from moisture, which helps to promote long-term reliability."
In extreme cases, a frozen battery's electrolytes can expand, leading to permanent damage if corrosive materials leak.
So, proper battery winterization isn't just about disappointing dead batteries in the spring. It's about reducing the risks that come with a bad lawn mower battery.
Types of Lawn Mower Batteries
There are primarily two types of batteries used in lawn mowers, each with its own storage requirements:
Lithium-Ion Batteries
Lithium batteries are popular for their lightweight design, fast charging times, and longer life. However, they can be sensitive to extreme temperatures, especially cold. If stored improperly, their performance may degrade over time.
Not all residential electric mowers take weatherization into account, but we'd be remiss to note that the John Deere Electric ZTrac 300 Series mowers are exceptions; the company employs the same technology in its residential mowers as it does agricultural-grade and construction products. (Batteries come with a 5-year/200-hour warranty, which consumers can extend to 10 years/400 hours.)
Lead-Acid Batteries
Lead-acid batteries are typically heavier and more robust but are also more susceptible to cold weather damage. Without proper maintenance and storage, these batteries can lose charge faster, and freezing temperatures can cause the electrolyte to freeze and expand.
How to Store Your Lawn Mower Battery for Winter
- Clean the Battery: Once disconnected, use a mixture of baking soda and water to remove any corrosion or dirt from the terminals and case.
- Charge the Battery: In colder temperatures, lithium-ion batteries should be stored at around 40-60% charge, while lead-acid batteries should be fully charged. A battery maintainer (a type of smart charger) will set the ideal charge level for winterization.
- Remove the Battery: If battery removal can be removed from the tool, disconnect it to prevent any residual power drain.
- Store in a Dry, Cool Place: Choose a dry location with moderate temperatures, ideally between 50°F to 80°F (10°C to 26°C). Avoid areas prone to freezing or extreme humidity.
- Use a Battery Tender: For lead-acid batteries, consider using a battery tender or trickle charger to keep the percent charge topped up without overcharging, preventing sulfation (a condition that damages the battery).
- Avoid Storing on Concrete Floors: Store the battery on a wooden shelf or bench. Leaving a battery on concrete leaves it exposed to temperature fluctuations which can deplete the battery over time.
- Inspect it!: Over the winter months, remember to check in. If the battery shows signs of corrosion, leaks, or significant loss of charge, address problems quickly. Damage can lead to a battery explosion or fire hazard.
Should you leave batteries plugged in all winter?
No — "It’s best to remove all batteries from your equipment and place them in a ventilated, climate-controlled area that remains dry and between 50°F-80°F all year round," explained Halfman. Leaving batteries connected to chargers or docking stations for months can cause self discharge, shorten battery life, and increase the risk of overheating.
How often should you check your stored battery during winter?
Check on them every month. Look for corrosion on the terminals, leaks, or a drop in charge.
Lead-acid batteries (including AGM batteries with lead plates) can lose charge faster in cold temperature storage, while rechargeable lithium batteries tend to hold charge longer.
Using float chargers or solar chargers can help keep lead batteries topped up safely without overcharging.
What else should be done before storing lawn gear for winter?
Batteries are only part of mower maintenance. Before winter storage:
- Check your spark plug, air filter, and fuel system
- Add a fuel stabilizer to the fuel tank of a gasoline-powered mower
- Change the engine oil and oil filter if needed.
- Clean the mower deck, apply a rust inhibitor, and protect it with a mower cover in a dry storage shed.
Whether you own zero-turn mowers, push mowers, compact tractor implements, or string trimmers, following these steps help your outdoor equipment last through the off-season and get ready for mowing season in spring.
