I would keep removable garden-tool batteries in a dry, secure place with steady temperatures, rather than leave them in a damp shed or patio box all winter. Take them out of the tools and follow the battery maker’s storage instructions. The mower or blower and its battery do not necessarily need the same winter home.
For a working collection of cordless tools, I find it more useful to organise by battery system than by machine. Keep the packs identifiable and their compatible chargers together in a dry area, with the batteries disconnected for storage. You should be able to reach what you need without rummaging among blades, screws or wet garden gear.
Can the batteries stay in the shed?
Only if the conditions meet the requirements for the exact battery and charger. A sound roof does not guarantee a dry interior: condensation, wet tools and rapid temperature changes can still be a problem. Look at the actual shelf or cupboard you plan to use, including what happens on cold mornings.
A dry garage or utility space may be more suitable, provided it stays within the manufacturer’s temperature range, is out of children’s reach and keeps the packs away from heat sources and direct sun. Do not choose a place where other equipment can fall on them or where they can drop from a high shelf.
Check the battery and charger instructions separately. Their permitted conditions may differ, and a temperature allowed for storage is not automatically suitable for charging. If your garden store becomes damp, it is not a suitable charging station.
How much charge should I leave in them?
Use the guidance for your battery system, not a single percentage applied to every brand. STIHL’s lithium-ion storage advice recommends 40–60% charge, shown by two LEDs on the batteries it describes.
EGO’s battery FAQ describes an automatic storage discharge function after 30 days of inactivity, bringing charge to around 30%. That is a feature of the batteries covered by its guidance, not something to assume every pack does.
Find the model number on your own battery and read its instructions before preparing it for a long break. Keep a brief note of the storage charge recommendation and any checking interval. Do not run a tool just to flatten the battery, or repeatedly recharge a pack to full all winter without a reason in its instructions.
Store the battery separately from the machine
Switch the tool off and follow the removal procedure before cleaning or putting it away. Where a battery is built in, do not dismantle the tool to remove it: the whole machine needs a suitable storage location.
Removing the pack does not winterise the rest of the equipment. A sprayer still needs its own cleaning and frost-storage routine; a mower still needs grass and soil cleared from it. Follow the machine’s instructions as well as the battery’s, particularly with equipment that holds liquid.
EGO’s winter mower guide advises removing the battery and safety key, drying the mower and keeping the battery separately in a dry location. My garden equipment storage guide helps with space for the larger machines.
Keep contacts clear and protect the casing
Use the maker’s recommended protective cover or storage arrangement where supplied. Do not put loose batteries in a drawer of metal fittings: screws, keys and other conductive objects must not bridge the terminals. Keep packs stable and protected from knocks rather than balancing them on top of equipment.
Inspect for a cracked casing, damaged contacts or other obvious changes before storing. If a pack has been submerged, badly damaged or has swollen, stop using it and seek the manufacturer’s advice. Do not open the casing or attempt a home repair.
Charging needs its own suitable space
Keep the charger dry and use the correct approved charger for the battery. Charge within the maker’s specified temperature range on a stable surface, with ventilation unobstructed. A cold battery may need time in an appropriate environment before charging; follow the manual rather than warming it on a radiator.
Do not charge inside a closed garden box, beneath fabric or on soft furnishings. Stay nearby, avoid overnight unattended charging and disconnect when the charge cycle is complete, following the product instructions. London Fire Brigade’s battery and charger guidance covers temperature extremes, damage and uncovered chargers.
A storage case helps organise equipment, but an ordinary case does not make a damaged battery safe or turn an unsuitable location into a charging area.
Before the first job after storage
Check the pack, contacts and charger again before use. Make sure everything is dry and within the permitted charging conditions. If warning lights appear, use the manual’s fault guide rather than repeatedly trying to force a charge.
For batteries that still work through winter, such as those used in a blower, keep following the normal charging routine and reserve long-term storage preparation for packs actually being put away. A simple labelled place for each battery system makes that much easier than treating the whole shed as one winter-storage job.
