# How to store mower batteries over winter

Source: https://mowandedge.co.uk/blog/how-to-store-mower-batteries-over-winter
Published: 2026-10-12
Publisher: Mow and Edge

**In short:** Clean the pack, charge it to the part charge level your manual recommends (many makers suggest around half), and store it indoors somewhere cool, dry and frost free, off the charger. Do not leave lithium packs in a freezing shed or garage all winter. Check the charge every couple of months and top up if it has dropped.

Most UK lawns get their last cut in October or November and the first in March or April. That leaves cordless mower batteries sitting for four months or more, often in a cold shed. Lithium-ion packs cope well with rest, but frost, damp and being left completely flat can shorten their life or leave them refusing to charge in spring. This guide covers the end of season routine, the right charge level, where to store packs and what to do if one will not stay charged when you bring it back out.

## End of season routine, step by step

Do this on your last mow of the year, while you remember. It takes ten minutes and protects the most expensive part of your kit.

1. Remove the battery from the mower and any other tools.
2. Let it cool to room temperature if you have just used it.
3. Brush clippings and dust off the pack and wipe it with a dry cloth. Keep the terminals dry.
4. Look for cracks, swelling, leaks or scorch marks. Recycle any damaged pack rather than storing it.
5. Charge or run it to the storage level your manual gives. Many makers suggest roughly half charge.
6. Take it off the charger and store it indoors in a cool, dry, frost free place.
7. Unplug the charger and store it with the pack, away from damp.

## What charge level to store at

Lithium-ion cells age fastest when kept full for long periods, and they can be damaged if they drift down to empty. A part charge is the usual compromise. Many manuals for cordless garden tools suggest storing at around 30 to 50 percent, or roughly two of four bars on the fuel gauge. Some makers simply say to store charged. Follow your own manual, because the advice varies.

Packs slowly self discharge, so check the gauge every couple of months. If it has dropped close to empty, give it a short charge back to the storage level.

| Do | Avoid |
| --- | --- |
| Store at part charge as the manual says | Leaving the pack flat for months |
| Keep indoors, cool and dry | Freezing sheds, garages and car boots |
| Store off the charger | Leaving it on charge all winter |
| Check charge every couple of months | Storing next to radiators, boilers or in sun |
| Keep terminals clean and dry | Damp floors, metal shelves with loose screws or tools |

Storage at a glance

## Where to keep packs in a UK winter

An unheated shed or detached garage often drops below freezing on clear nights. Cold storage is not usually instantly harmful to a lithium pack at rest, but makers give a storage temperature range, and repeated frost and damp are hard on the pack and its electronics. Charging a frozen pack is a bigger risk, and most chargers will refuse until it warms up.

A utility room, a cupboard under the stairs or a spare room shelf is better. Keep packs away from heat sources such as boilers and radiators, out of direct sun and out of reach of children. Store them on a stable surface, not loose in a box where the terminals can touch keys, screws or other metal.

Note: Lithium batteries: use only the maker's charger for your pack, do not charge or use a pack that is swollen, cracked, leaking or has been dropped hard, and store packs away from heat, direct sun and frost. Take worn or damaged batteries to a proper battery recycling point, never household waste.

## Battery will not stay charged in spring

If a pack shows full but runs for a few minutes, or drops from full to empty overnight, it may have lost capacity with age or been left too low over winter. First let it reach room temperature, clean the contacts and give it a full charge on the maker's charger. Run the mower on a dry lawn with the cut raised for the first session; long wet spring grass drains any pack quickly.

If it still fails, or the charger shows a fault light, see our guide to a [cordless mower battery not charging](https://mowandedge.co.uk/blog/cordless-mower-battery-not-charging). A worn pack should be replaced with the maker's own battery and the old one taken to a recycling point.

## How long to charge a lawn mower battery

Charge time depends on the pack's amp hours and the charger's output. A small 2 Ah pack on a fast charger can be ready in under an hour, while a large high Wh pack on a standard charger can take several hours. Your manual or the listing gives the time for your pairing. Our explainer on [mower battery voltage](https://mowandedge.co.uk/blog/mower-battery-voltage-explained) shows how to work out a pack's watt hours.

Before the first cut of spring, charge every pack fully and check the mower too: clean the deck, check the blade and set the cut high. If your old mower is due for retirement, our [cordless lawn mower guide](https://mowandedge.co.uk/best/best-cordless-lawn-mower) compares current models and the batteries supplied with them.

## Frequently asked questions

**Can I leave my mower battery in the shed over winter?** It is better not to. Unheated sheds can freeze and get damp. Bring packs indoors to a cool, dry, frost free spot and keep them off the charger.

**Should I store a mower battery fully charged?** Many makers suggest part charge, often around half, for long storage. Some say to store charged. Follow your manual, and top up if the gauge drops near empty.

**Can I leave the battery in the mower over winter?** Remove it. Storing it separately keeps it away from cold and damp and prevents any slow drain or accidental starting.

**What do I do with an old mower battery?** Take it to a battery recycling point, such as a household waste recycling centre or a shop collection bin that accepts larger packs. Never put lithium batteries in household waste or kerbside bins.

## Buying guides on this topic

- https://mowandedge.co.uk/best/best-cordless-lawn-mower
- https://mowandedge.co.uk/best/best-cordless-mower-for-small-garden
- https://mowandedge.co.uk/best/best-cordless-strimmer