A battery left sitting slowly discharges, and a discharged lead-acid battery can be damaged by cold and by sulfation. Seasonal machines like mowers, motorcycles, ATVs, boats and tractors sit long enough for that to happen. AMSOIL does not sell batteries or chargers; this page is general care information. Follow your battery and equipment manufacturer’s instructions, especially for lithium batteries, which have their own charging rules.
Charger, maintainer or neither?
- Battery maintainer (float charger): designed to stay connected and hold a full battery at a safe level during storage. This is the usual choice for seasonal equipment.
- Standard charger: brings a low battery back up. Many are not meant to be left connected for months.
- Disconnect and recharge: if you cannot leave a maintainer connected, disconnect the negative cable and top the battery up every month or two.
- Battery chemistry matters. Use a charger or maintainer with the right mode for flooded, AGM, gel or lithium batteries.
Safety
Lead-acid batteries can give off hydrogen gas while charging. Charge in a ventilated space away from sparks and flames, wear eye protection, connect and disconnect in the order the charger manual gives, and never charge a frozen battery.
Fall battery storage checklist
- Fully charge the battery before storage.
- Clean the terminals and cable ends, and check for cracks, bulges or leaks in the case.
- Check electrolyte on serviceable flooded batteries and top up only with distilled water, per the battery maker.
- Connect a maintainer with the correct mode, or disconnect the negative cable to stop small drains.
- Store it clean, dry and off freezing ground if you remove it, and away from children and pets.
- Protect nearby metal such as hold-down brackets and trays from corrosion.
- In spring, check voltage, recharge if needed and reconnect positive first, then negative.
Frequently asked questions
Should I take the battery out of my mower for the winter?
It is optional. If the machine sits somewhere you can safely run a maintainer, leaving it in is fine. Otherwise remove it, charge it and store it somewhere it will not freeze.
Can I leave a regular charger on all winter?
Only if the manufacturer says it is designed for that. A maintainer or float charger is built to stay connected.
Do lithium powersports batteries need special care?
Yes. Many require a lithium-compatible charger and have their own storage instructions. Follow the battery maker’s guidance.
AMSOIL products for this job
- AMSOIL MP Metal Protector. AMSOIL says: “Excellent for drying electrical systems and as a penetrating oil”; “Helps protect against rust and corrosion, even in salt water”.
- AMSOIL Heavy-Duty Metal Protector. AMSOIL says: “Protects against the effects of salt, moisture and chemical corrosion”; “Sprays into hard-to-reach places and works as an undercoat”.
- AMSOIL Gasoline Stabilizer. AMSOIL says: “Helps keep fuel fresh up to 12 months”; “Protects against varnish and gum buildup”.
Use metal protectants on brackets, trays and exposed hardware; follow the battery maker’s directions for the terminals themselves.
Product wording above is quoted or summarized from amsoil.com. Read each product’s label and data sheet for directions.
Use AMSOIL’s official lookup guide to see what is listed for your vehicle or equipment, then order online whenever it suits you.