Before you begin. This procedure is general reference information, not professional advice. Equipment varies by manufacturer, model, and year. Always follow the documentation supplied with your equipment — where it differs from this page, follow the manufacturer. Verify that you have the tools, the working conditions, and the ability to do this task safely. If anything is unclear, if the equipment is damaged, or if the task exceeds your experience, stop and use a qualified professional. You are responsible for your own safety and for the outcome. This site accepts no liability for any loss, damage, or injury arising from the use of this information.
Specifications marked unverified could not be traced to a manufacturer source. Do not rely on them — obtain the value from your equipment documentation.
Summary
A cordless mower battery left in an unheated shed all winter is a battery you buy again in spring. That is the ordinary, expensive version of getting this wrong. The rarer and much worse version is a damaged pack put away unnoticed, because a lithium-ion pack that fails does so as a fire, and the place people store them is usually attached to the house.
The part of this that surprises people is that the manufacturers do not agree about the most basic instruction, and this page publishes the disagreement rather than picking a winner. DEWALT's storage recommendation for long storage is a fully charged battery pack, and it warns that packs should not be stored completely depleted of charge. STIHL's published answer to 'a STIHL battery should be fully charged before storage' is simply False, and its figure is a charge between 40% and 80%. EGO's own battery manual says to store packs in a 30%-50% charged condition, and to fully charge them every six months of storage. Those are three tier-one manufacturers giving three answers about their own products, and the correct action is to follow the one that made your pack. Everything else here — where to put them, what to check first, what temperature the shed must not reach — is more consistent than you might expect.
Necessary equipment
| Item | Note |
|---|---|
| Charger for your own packs | Use only the charger that the manufacturer of the pack gives. |
| Documentation for your own packs | The manufacturers do not agree about the state of charge for storage. |
| Thermometer | A thermometer shows the temperature in the storage place. |
| Clean dry cloth | Use a dry cloth on the outside of a pack. |
| Non-metal storage box optional | A box keeps the metal objects away from the terminals. |
Collect the packs and the documentation
Estimated 10 min to 30 min
- Collect every battery pack from the equipment and from the shed.5mReport a problem with step 1, Collect the packs and the documentation
- Remove each pack from its tool.
- Do not leave a pack in a tool with a locked switch.
- DEWALT tells you not to store a pack in a tool with the trigger switch locked on.
READ THE DOCUMENTATION FOR YOUR OWN PACKS FIRST.
Three manufacturers give three different states of charge for storage.
- Find the documentation for each pack.5mReport a problem with step 2, Collect the packs and the documentation
- The maker of the pack is on the label of the pack.
- Get the documentation from the website of that maker.
- The instruction for your pack is the instruction to obey.
Examine each pack
Estimated 13 min to 28 min
- Clean the outside of each pack with the dry cloth.2mReport a problem with step 1, Examine each pack
- Remove the grass and the soil from the vents.
- Do not put a pack in water.
DO NOT PUT A DAMAGED PACK INTO STORAGE.
DEWALT tells you to return a pack with a crack to a service centre. A damaged pack can catch fire.
- Look at the case of each pack for a crack or damage.3mReport a problem with step 2, Examine each pack
- DEWALT refuses a pack with a case that has a crack or damage.
- EGO refuses a pack with damage or a modification.
- Look for a case that is not the correct shape.
KEEP EVERY METAL OBJECT AWAY FROM THE TERMINALS.
A metal object across the terminals makes a short circuit. The pack becomes very hot and can burn you.
- Look at the terminals of each pack.2mReport a problem with step 3, Examine each pack
- Look for a bent terminal and for corrosion.
- Look for a metal particle between the terminals.
- Smell each pack and touch each pack.1mReport a problem with step 4, Examine each pack
- A pack with an unusual smell has a fault.
- A pack that is warm many hours after use has a fault.
DO NOT PUT A PACK IN HOUSEHOLD WASTE.
DEWALT tells you to return a damaged pack to a service centre. A pack in a waste vehicle can catch fire.
- Keep a pack with damage away from the other packs.5mReport a problem with step 5, Examine each pack
- Put the pack outside on a non-flammable surface.
- DEWALT tells you to return the pack to a service centre.
- Speak to the service centre about the transport of the pack.
Set the state of charge
Estimated 15 min to 1 hr 7 min
Source: DCB115 Charger Instruction Manual (with lithium-ion battery pack safety and storage instructions) · tier 1 · accessed 2026-07-29
Source: Battery Storage — How to Store Batteries · tier 1 · accessed 2026-07-29
Source: 56V Battery 2.0Ah/2.5Ah/4.0Ah/5.0Ah/7.5Ah Operator's Manual · tier 1 · accessed 2026-07-29
Source: DCB115 Charger Instruction Manual (with lithium-ion battery pack safety and storage instructions) · tier 1 · accessed 2026-07-29
Source: DCB115 Charger Instruction Manual (with lithium-ion battery pack safety and storage instructions) · tier 1 · accessed 2026-07-29
Source: 56V Battery 2.0Ah/2.5Ah/4.0Ah/5.0Ah/7.5Ah Operator's Manual · tier 1 · accessed 2026-07-29
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
DO NOT PUT A DAMAGED PACK INTO A CHARGER.
DEWALT gives this instruction for a case with a crack. The pack can catch fire.
- Read the state of charge that your own manufacturer gives.3mReport a problem with step 1, Set the state of charge
- DEWALT gives a fully charged pack for long storage.
- STIHL gives a charge between 40% and 80% for its packs.
- EGO gives a 30% to 50% charged condition for its packs.
- These three answers are different. Do not use a number between them.
DO NOT PUT A PACK INTO STORAGE WITH NO CHARGE.
DEWALT states that a pack must not go into storage completely depleted of charge.
- Charge or discharge each pack to that state of charge.10mReport a problem with step 2, Set the state of charge
- Read the state of charge from the indicator on the pack.
- STIHL uses two green LEDs for 40% and three green LEDs for 80%.
- Charge each pack in air between 65 and 75 degrees Fahrenheit.2mReport a problem with step 3, Set the state of charge
- DEWALT gives this air temperature for the longest life.
- DEWALT refuses a charge below 40 or above 104 degrees Fahrenheit.
- EGO gives 41 to 104 degrees Fahrenheit for a charge.
Select the storage place
Estimated 10 min to 30 min
Source: DCB115 Charger Instruction Manual (with lithium-ion battery pack safety and storage instructions) · tier 1 · accessed 2026-07-29
Source: Battery Storage — How to Store Batteries · tier 1 · accessed 2026-07-29
Source: Battery Storage — How to Store Batteries · tier 1 · accessed 2026-07-29
Source: 56V Battery 2.0Ah/2.5Ah/4.0Ah/5.0Ah/7.5Ah Operator's Manual · tier 1 · accessed 2026-07-29
Source: 56V Battery 2.0Ah/2.5Ah/4.0Ah/5.0Ah/7.5Ah Operator's Manual · tier 1 · accessed 2026-07-29
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
DO NOT STORE A PACK IN A METAL BUILDING IN SUMMER.
DEWALT names this place. Heat above the limit damages the pack and it can catch fire.
- Select a place that is cool and dry and away from the sun.5mReport a problem with step 1, Select the storage place
- DEWALT gives a place that is cool and dry, away from direct sunlight and excess heat or cold.
- STIHL gives a dry area that is away from direct sunlight.
- EGO refuses the storage of a pack outside or in a vehicle.
- Measure the temperature of that place in summer and in winter.5mReport a problem with step 2, Select the storage place
- DEWALT refuses a place at 104 degrees Fahrenheit or more.
- STIHL gives no lower than 14 and no higher than 122 degrees Fahrenheit.
- EGO gives a maximum of 80 degrees Fahrenheit for storage of more than 30 days.
- The three limits are different. Use the limit for your own pack.
Put the packs into storage
Estimated 9 min to 17 min
DO NOT LEAVE A PACK IN THE CHARGER FOR STORAGE.
DEWALT gives storage out of the charger.
- Remove each pack from the charger.1mReport a problem with step 1, Put the packs into storage
- DEWALT gives storage out of the charger.
- STIHL tells you to remove the plug of the charger from the outlet.
KEEP THE PACKS AWAY FROM MATERIALS THAT BURN.
A pack that fails makes a fire that water does not extinguish.
- Put each pack in the non-metal box with a space between the packs.3mReport a problem with step 2, Put the packs into storage
- Install the terminal cover if your pack has one.
- Do not put screws, nails or coins in the same box.
- Put the box away from materials that burn.3mReport a problem with step 3, Put the packs into storage
- Keep the box away from paper, cloth and liquids that burn.
- A hard floor below the box is better than a wood shelf.
- Write the date and the state of charge on a label.2mReport a problem with step 4, Put the packs into storage
- Put the label on the box.
- The date tells you when to do the next check.
Return the packs to use
Estimated 16 min to 1 hr 20 min
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
- Examine the packs after six months of storage.5mReport a problem with step 1, Return the packs to use
- EGO tells you to fully charge a pack every six months of storage.
- Look at the case and the terminals again.
- Let a cold pack become warm before you charge it.3mReport a problem with step 2, Return the packs to use
- DEWALT refuses a charge at less than 40 degrees Fahrenheit.
- Put the pack in the house for some hours.
- Charge each pack before the first use of the season.5mReport a problem with step 3, Return the packs to use
- EGO tells you to fully recharge a pack that was in storage for a month or longer.
- DEWALT states that a pack needs a charge again after storage.
- Examine each pack again before you put it in a tool.3mReport a problem with step 4, Return the packs to use
- A pack that does not accept a charge goes to a recycler.
- A pack that is not the correct shape goes to a service centre.
Terminology
This page uses one term for each item and holds it throughout, as ASD-STE100 requires. Equipment sellers and other guides use the names below for the same parts.
- lithium-ion battery pack
- Also called: battery, batteries, tool battery, li-ion battery, lithium battery, pack, mower battery
- state of charge
- Also called: charge level, how full it is, percentage, SoC, bars on the battery
- charge indicator
- Also called: battery gauge, charge meter, the green lights, LEDs, battery meter, power gauge
- storage temperature
- Also called: shed temperature, garage temperature, how cold is too cold, freezing, winter temperature
- deep discharge
- Also called: flat battery, dead battery, completely drained, run down, won't take a charge
When to use a professional
Stop if a pack is not the correct shape. Stop if a pack has an unusual smell. Stop if a pack is hot many hours after use. Put the pack outside on a surface that does not burn. Then speak to the manufacturer or to a battery recycler.
Do not open a battery pack. DEWALT gives a warning about a fire hazard and tells you never to open a pack for any reason. Only the manufacturer and an authorised service provider must do work on a pack.
Do not put a lithium-ion pack in household waste. Do not put a pack in a kerbside collection container. Speak to a service centre or to a battery recycler about the correct route.
Do not use water on a lithium-ion fire. Leave the building and call the emergency number for your country. Tell the responders that the fire is a lithium-ion battery.
Do not repair a pack. Do not change a pack to fit a charger from a different maker. DEWALT warns that a pack can rupture and injure you.
Common questions
Should I store tool batteries fully charged or half charged?
It depends entirely on who made the pack, and this is the one question where the manufacturers openly disagree. DEWALT's storage recommendation is that for long storage it is recommended to store a fully charged battery pack in a cool dry place out of the charger. STIHL puts the proposition 'a STIHL battery should be fully charged before storage' to its readers and answers it False, giving 40% to 80% instead. EGO's own battery manual says to store packs in a 30%-50% charged condition and to fully charge them every six months of storage. Follow the one printed by the maker of your pack, and do not average them — there is no state of charge halfway between 'full' and '30%' that any of the three stands behind.
Can I leave batteries in the shed over winter?
Measure the shed before you decide, because the limits are not the same for every brand. DEWALT tells you not to store the pack where the temperature may reach or exceed 104 °F (40 °C) and specifically names outside sheds and metal buildings in summer. STIHL gives an outer range of no lower than 14°F and no higher than 122°F, with a best range of 50°F to 68°F. EGO wants below 80°F (26°C) for storage longer than 30 days and says plainly not to store the pack outside or in vehicles. A shed that satisfies STIHL's outer range can be well past what DEWALT and EGO permit, which is exactly why this page will not print one number.
Is it the cold or the heat that kills tool batteries?
Heat is the one the manuals are strictest about, and it is the one people underestimate because they are thinking about winter. The temperature ceilings are what the makers write in bold — DEWALT's 104 °F refusal names a metal building in summer, and EGO caps long storage at 80°F. Cold matters differently: it does not usually destroy a stored pack, but charging a cold pack does, which is why DEWALT refuses a charge in air below +40 °F (+4.5 °C). Bring a cold pack indoors and let it warm before it goes near a charger.
Can I leave the battery on the charger all winter?
No, and both of the makers who mention it say to take it off. DEWALT's storage recommendation is explicitly to store the pack out of the charger, and STIHL's storage guidance is to unplug the charger from the wall outlet before storing. A charger left plugged in for months is a mains-connected appliance nobody is looking at, sitting next to the thing you are trying to protect. Take the pack off, take the charger out, and store them separately.
What does a battery that is about to go wrong look like?
Look for a case that is cracked, swollen or no longer the shape it was, a smell you do not recognise, and warmth hours after the last use. DEWALT's instruction is that if the battery pack case is cracked or damaged, do not insert it into the charger, and that a pack whose plastic housing breaks or cracks goes back to a service centre for recycling. EGO similarly refuses a battery pack that is damaged or modified. A pack that fails one of those checks does not go into the box with the others — it goes outside, onto something that will not burn, and then to the manufacturer.
How do I get rid of a dead or damaged tool battery?
Not in the bin and not in the kerbside recycling box. DEWALT's route for a damaged pack is a service centre for recycling, and if a pack no longer holds a charge it points owners to a DEWALT service centre for free disposal. The reason the route matters is the compaction that happens inside a waste vehicle, which is exactly the mechanical abuse a lithium cell responds to worst. Ring the service centre before you travel and ask how they want it packed and carried.
My battery is completely flat. Have I ruined it?
Possibly, and it is the one failure mode a storage routine is meant to prevent. DEWALT's note is direct: battery packs should not be stored completely depleted of charge. A cell that sits at zero for months can fall below the voltage its protection circuit will allow a charger to work with, at which point the charger simply refuses it and there is nothing an owner can safely do about that. Try a charge at room temperature once; if the charger will not start, treat the pack as end-of-life and recycle it rather than attempting anything clever.
Do I need to do anything to the batteries in the middle of storage?
EGO is the maker that publishes an interval for this: every six months of storage, fully charge the pack. Its manual also notes that the pack performs a self-discharge operation after about a month of storage, and that a pack stored for a month or longer should be fully recharged before the next use. The other two manuals read for this page do not give a mid-storage interval at all. Put the date on the box when it goes away and you will not have to remember.
Related procedures
Sources
Every specification on this page is traced to one of these sources. Tier 1 is a manufacturer document, a published standard, or a government safety authority. See Standards for the full tiering rule.
- Tier 1DCB115 Charger Instruction Manual (with lithium-ion battery pack safety and storage instructions)
- Tier 1Top 10 Lithium Ion Battery Storage & Safety Tips
- Tier 1Battery Storage — How to Store Batteries
- Tier 156V Battery 2.0Ah/2.5Ah/4.0Ah/5.0Ah/7.5Ah Operator's Manual
Revision history
Current version 1 · updated 2026-07-29 · next review due 2027-07-29
- v1 · 2026-07-29First draft. Three tier-1 manufacturer documents read on 2026-07-29: the DEWALT DCB115 charger and battery instruction manual, STIHL's published battery storage guidance, and the EGO 56V battery operator's manual (text-extracted locally from the PDF). The state of charge for storage and the storage temperature limit both carry a genuine three-way manufacturer disagreement and publish as such, naming all three sources; no midpoint is offered anywhere on the page. Nothing is presented as a general rule for all packs. A CPSC lithium-ion battery page was sought as a fourth, government-tier source and could not be read; it is recorded under rejected.
Corrections to this page are listed in the public corrections log. Reports that are credible and not yet verified are listed in the public errata register, and an open one renders above the step it concerns.
Comments and corrections
Found an error? A correction with a manufacturer source is applied and logged publicly. You can also write to corrections@fixchecklist.com.
Every step above carries its own report control, which tags the report with that step so a correction reaches the right place. For anything about the procedure as a whole — the order of the sections, a step that is missing, something that did not match your equipment — use this: report something about this whole procedure.