How to Store Lawn Mower Battery for Winter? | Keep It Alive

Store the lawn mower battery indoors in a cool, dry place; lithium-ion packs hold about 40% charge, while lead-acid batteries store fully charged.

For the full breakdown, see our best Batteries For Lawn Mowers guide.

The way you store a lawn mower battery for winter decides whether it starts in spring or ends up as a dead brick on a shelf. The right method depends on which battery your mower uses, and getting it wrong costs you a replacement. Here is the short version: remove the battery if you can, pick a spot above freezing, and charge it to the level that suits its chemistry. The table below lays out both types at a glance, and the sections after it cover the how and why.

Lithium-Ion vs. Lead-Acid: What Changes For Storage

The single biggest variable is battery chemistry. A lithium-ion pack and a lead-acid battery need opposite treatment, and mixing them up is the most common winter mistake.

For lithium-ion, the goal is a partial charge. Battery University’s storage guidelines recommend storing lithium-ion cells at roughly 40% charge to minimize stress and capacity loss. Either level works; the point is to avoid a full charge and to never store the pack completely dead.

Lead-acid is the opposite. Husqvarna instructs owners to store lead-acid batteries fully charged and to recharge them every second month during winter. A stored lead-acid battery slowly self-discharges, and letting it sit low damages the plates permanently.

The Right Spot And The Conditions That Matter

Temperature and moisture are the two forces that kill stored batteries. A garage that stays above freezing and dry works well; an unheated shed that dips below freezing does not.

Step-By-Step: Preparing Your Mower Battery

Removing the battery is the cleanest route, but not every mower allows it. Here is the sequence that works for both scenarios.

• Remove the battery from the mower. If it is fixed and non-removable, STIHL notes you must winterize the mower as a whole and store the unit in a warm, dry place.
• Clean the terminals and mask off the contact points to prevent accidental shorting. STIHL specifically recommends masking the contacts on cordless mower batteries.
• Charge to the right level: about 40–75% for lithium-ion, full for lead-acid.
• Disconnect leads or cables on lead-acid batteries, and place the battery in a clean, dry, well-ventilated location away from direct sunlight, radiators, and heating ducts.
• Check on it periodically. For lead-acid, Husqvarna says recharge every second month.

One caveat applies to every chemistry: never stack the battery against metal objects, and keep it out of sealed enclosures. Terminals that touch metal create a short, and a sealed box traps the gases a lead-acid battery can emit.

FAQs

Can I leave the battery in the mower all winter?

Only if the battery is permanently fixed. For removable packs, taking them out is the safer choice because it keeps the battery in a controlled indoor temperature while the mower sits in the cold. A fixed battery means the whole mower needs a warm, dry storage spot instead.

Is a cold garage too cold for battery storage?

It depends on whether the garage stays above freezing. A garage that hovers around 50°F works fine, but one that dips below 32°F risks damage, especially to a discharged battery. If your garage freezes, move the battery inside the house to a dry room.

How often should I recharge a stored battery?

For lead-acid batteries, recharge every second month during winter to prevent damage from prolonged low charge. Lithium-ion packs need no scheduled charging if stored at the correct partial charge, though a quick check mid-winter never hurts.