Lithium-ion batteries have transformed power tools, making them lighter, more powerful and cordless. They are a staple on Australian worksites, in home workshops and garages. Like all lithium batteries, they carry a fire risk that is worth understanding and managing.
This page covers the specific risks of power tool batteries, safe charging and storage habits, and how to respond if something goes wrong.
For a broader overview of lithium battery fire safety, see our Lithium Battery Fire Safety Guide.
How Power Tool Battery Fires Start
Most power tool battery fires are triggered by thermal runaway — caused by one or more of the following:
- Charging a damaged or dropped battery — impact damage that is not visible externally can cause internal short circuits
- Overcharging or charger faults — a faulty charger or charger left unattended on a degraded battery can push cells past their safe limit
- Charging a hot battery — placing a battery on charge immediately after heavy use, before it has cooled, increases thermal stress
- Degraded cells — older batteries that have gone through many charge cycles have reduced tolerance for charging and heat
- Heat exposure — batteries left in direct sun or a hot vehicle can reach unsafe internal temperatures before use or charging even begins
Safe Charging for Power Tool Batteries
Good charging habits significantly reduce your risk:
- Use the manufacturer's charger — always use the charger designed for your specific battery platform and brand
- Allow batteries to cool before charging — after heavy use, let the battery rest for at least 15–20 minutes before placing it on charge
- Charge on hard, non-flammable surfaces — avoid charging on timber workbenches covered in sawdust, fabric or near solvents
- Don't leave charging batteries unattended overnight — charge during the day when you can monitor them
- Avoid fast-charging older packs — degraded batteries are more vulnerable to the heat stress of rapid charging
- Inspect before charging — do not charge a battery that is cracked, swollen, wet or has been dropped from height
Safe Storage for Power Tool Batteries
How and where you store power tool batteries matters, particularly when storing multiple packs:
- Store battery packs in a cool, dry location, away from areas that get very hot in summer such as metal sheds without ventilation
- Keep batteries away from flammable materials such as timber offcuts, rags, solvents and fuel
- Do not stack batteries directly on top of each other without separation. Heat from one pack can transfer to adjacent packs.
- Store in original cases or purpose-built battery organisers where possible
- Inspect packs regularly for cracks, swelling or corrosion — remove any damaged packs from storage immediately
- Dispose of old or damaged batteries correctly at a designated battery recycling point — do not place in general waste
What to Do If a Power Tool Battery Catches Fire
Always call 000 immediately for any significant fire. Follow emergency services guidance at all times.
For early-stage incidents where it is safe to intervene:
- Do not use dry powder (ABE) as a first choice — it does not address the ongoing heat source and leaves heavy residue across your workshop
- Apply a purpose-built lithium suppression agent directly to the battery surface to help cool and suppress the incident
- Do not attempt to move a burning battery pack — disturbing a burning lithium battery can cause unpredictable reactions
- Evacuate the area and avoid inhaling smoke or gases. Battery fires produce toxic fumes.
- If the battery is on charge when the incident starts, disconnect power at the wall if it is safe to do so
- Even after apparent suppression, monitor the battery — power tool batteries can reignite after the initial incident
Choosing a Fire Extinguisher for Power Tool Battery Fires
Standard ABE dry powder extinguishers can knock down visible flame but are not designed to address the ongoing heat source in a lithium battery fire, and leave heavy powder residue across tools and equipment.
BSA extinguishers use BSA900™, a water-based suppression agent designed to:
- Help cool and reduce battery surface temperature
- Cling to surfaces for extended cooling contact
- Help suppress flame and reduce oxygen exposure
Recommended sizes for power tool environments:
2L
Suited to a small home workshop or single charging area
4L
Suited to garages and sheds where multiple battery packs are stored or charged
9L
Suited to larger workshop environments with multiple tool platforms and high battery pack volumes
Frequently Asked Questions
Is it safe to leave power tool batteries on the charger overnight?
It is not recommended. Leaving batteries on charge overnight or when unattended removes your ability to respond early if something goes wrong. Charge during the day when you can monitor them.
Can I store multiple battery packs together?
Yes, but with care. Keep packs separated, away from flammable materials, and in a cool dry location. Inspect them regularly. A fire in one pack can expose adjacent packs to heat, so separation and a clear area around your storage zone matters.
What size extinguisher do I need for a workshop?
For a typical home garage or shed with a moderate number of battery packs, a 4L BSA extinguisher is a practical choice. For larger workshop setups with multiple platforms and high battery pack volumes, a 9L unit provides greater suppression capacity. View the full range to compare options.
Are aftermarket batteries more dangerous?
Aftermarket and third-party battery packs vary significantly in quality. Some do not include the same thermal management circuitry or cell quality as OEM packs. Using only manufacturer-approved batteries and chargers is the safest approach for reducing thermal runaway risk.
Battery Safe Australia was founded to bring purpose-built lithium fire protection into everyday Australian homes and workplaces.
View BSA Lithium Fire Extinguishers →